Comsol symmetry geometry. This method is called boundary representation, .
Comsol symmetry geometry When the Include circumferential displacement check box is selected, many nodes in the Model Builder show additional user inputs, such as fields to apply loads in the azimuthal direction (right). They are selected from the More 2D Datasets and More 3D Datasets submenus. See Virtual Geometry and Mesh Control Operations for examples of how to use virtual geometry operations to remove a short edge and to ignore and collapse edges to prepare the geometry for efficient meshing. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. (Right-click on Geometry and select Boolean Operations>Partition) Add the object to partition to the list. In the 2D axisymmetric formulation, the angular dependence of the electric field is given by e^{-j m \phi} , where m is an integer that is specified by the user. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or Editing a 2D geometry in the Graphics window. Today, we will demonstrate the steps we outlined with a 3D generator model example, comparing our results with an analogous 2D model. The Geometry node in the model tree of the COMSOL Multiphysics simulation software contains an ordered sequence of geometry operations. The COMSOL Multiphysics ® software contains a plethora of geometry tools, operations, and other functionality that provide you with a number of ways to create the geometry for your model. From your image the way you have cut your domain it looks like you should have antisymmetry on some of the fluxes, even if you want symmetry on the geometry and shape. but later on I want to add other components on the geometry which do not have this symmetry, and The check boxes in the Axial Symmetry Approximation section enable circumferential displacements in 2D axisymmetric models (left). In the COMSOL Learn how to create a plot using the Mirror, Extrusion, and Sector Data Sets to visualize the results from a model with symmetry. Keep in mind that COMSOL recognizes symmetry through the physics, not the actual geometry. Dear all, sorry the continuous questions today! I am going to use symmetry for the geometry as in the picture I attached. This can be used to model some situations where you want a plane One of my fellow students modeled a rather complex geometry in Comsol 3. There is a different analysis procedure, mainly in solid mechanics, called cyclic symmetry for solving a rotationally symmetric structure under general (non-rotationally symmetric sounds like you can do it in 2D axial symmetry. Two types of symmetry boundary Using symmetry is one of the most effective ways to reduce the size of a model. That said, I wonder if you may be, at least in part, confusing symmetry in geometry with symmetry in the EM fields. In reality the eigenmodes are known to be perfectly symmetric/antisymmetric. In 3D components, the Planes intersection line can be set Along the x-axis, Along the y-axis, or Along the z-axis. Symmetries can often greatly reduce the size of a model and hence reduce the memory requirements and solution time. The Perfect Electric Conductor boundary condition sets the tangential component of the electric field to zero. I’m performing a linear buckling analysis, and my geometry has a three-fold (120°) rotational symmetry. m. Can COMSOL solve for these modes? While I’ve had some success with basic symmetry cases, I’m still struggling to correctly define rotational symmetry for my cross-section. My problem is that the mode index and the e-field distribution at the port side i find with respectively the boundary mode analysis and the frequency domain study How should I plot 1d curves or 2d surfaces by symmetry? Dr Koslover in a 3d half model, mirror data 3d can be used to plot 3d stuff. The symmetry plane is formed by the normal to the membrane surface and the edge tangent. For the latter I will need to explore different crystal cuts, therefore I defined a rotated system for the material. Rotation and reflection are only available when using an even number of sectors. It is, however, possible to change this using the settings in the Position, Axis (3D only), and Rotation Angle sections. This tutorial shows how planes of symmetry can be used in a 3D model to reduce the finite element model size and make the simulation faster. But when plotting 1d curves or 2d surfaces, mirror data 2d doesn't seem to work and there's no mirror data 1d even. It controls the sign of the flux. When creating a model, one of the first steps you must take is to build the geometry. The position of the point along the intersection line can be arbitrary as it does not change the planes definition. 0, you can hover your mouse over geometry in the Graphics window and the associated geometry label will automatically be displayed on the left side of the Graphics window. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The model geometry for a flange is partitioned using a block as the tool object (left) in order to reduce the flange to a quarter (right). The options for the Symmetry type setting for the Symmetry Plane boundary condition. Enter a point on the rotation axis in the x, Show in 3D if in a work plane’s plane geometry) list: All levels, Domain selection, Boundary selection, Edge selection, or Point selection. This is useful if you have created a parametric curve with the right shape but The Shell-and-Tube Heat Exchanger tutorial model geometry (left). Unfortunately the space dimension should be solved in a cylindrical 2D dimension. Therefore, the physical components of the radial and axial displacement, u and w, are used by default as dependent variables for the axially symmetric geometry. I have built my geometry, then i took a workplane and use the partion object function. This can be useful for visualization of a solution to an axisymmetric problem. Does In many cases symmetry of the geometry and loads can be used to your advantage in modeling. Figure 1: The Well, you need to build only half the geometry (or build the entire geometry and then delete 1/2 of it). The Magnetic Insulation Boundary Condition The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. I draw a rectangle which has a heigth of pipe radia (not dia), and draw another rectangle on the first rectangle having a height of pipe wall thickness. Neither has COMSOL allowed to define a "cut plane" for a 3D geometry to export a projection as a 2D geometry to be used in 2D or 2Daxi The Geometry Analysis subnode to the Coil feature automatically appears to set up the automatic computation of the current flow in the coil. Normal Direction Condition. The COMSOL Multiphysics UI showing the Model Builder with the Coil feature selected, the corresponding Settings window, and the dynamic speaker model in the Graphics window. This includes custom tools for building certain kinds of geometries, such as those exhibiting a type of Here is a figure (from the internet) that shows what I think Chong means by cyclic symmetry. This Next, using the geometry from the shell-and-tube heat exchanger tutorial model, we demonstrate exploiting the symmetry of an object to simplify a simulation. For each of the regions shown in the figure we will set up selections that contain the corresponding domains in the geometry. In many cases symmetry of the geometry and loads can be used to your advantage in modeling. The design and physics are symmetric along the XZ-plane, enabling us to simplify the geometry by removing half (right). Specify in this feature an arbitrary vector field that defines the direction of the wires in the coil. Then, under the Physics set-up, right-click and define a symmetry boundary The 2D axisymmetric implementation in COMSOL Multiphysics by default assumes independence of the azimuthal component of the displacement. This node is available only in 2D axisymmetry, where the only possible symmetry plane is normal to the Z-axis. 5 in a cartesian 2D geometry. This is Chapter 2 of 3 in an Advanced If the model represents only a part of a geometry obtained from symmetry cuts (for example, a quarter of a circle), use the settings under Symmetry specification to specify appropriate correction factors. In Part 2 of the course, we cover how to expand a 2D geometry into 3D using a variety of the built-in operations in COMSOL Multiphysics ®. Because of the large size of my geometry and the symmetry of the problem I use the 2D axisymmetric settings. The corresponding 3D geometry results from a revolution around the z-axis. Point on Axis of Rotation . You can allow a symmetry plane to move along its normal direction. EST. This is visualized in the table below for clarity, using an example of a viscoelastic damper. It is a 2D axisymmetric problem and the geometry is a half circle. When I apply the meshing, it always give finer mesh for upper half part of the geometry while I need a symmetric meshing for lower and upper part and finer mesh around the center. Click the Angles button to specify the start angle (default: 0 degrees) and end angle (default value: 360 degrees; that is, a full revolution) of the revolution. Is it the same like to draw or build only the half geometry. Its Equation View subnode displays all contributions to the spatial frame deformation, for example the mesh smoothing equations used by a Deforming Domain feature, or the boundary motion implicitly prescribed by a Solid Mechanics interface. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or 2D-axi means you have cut your cylindrical symmetry cases along a (work)plane of dimension by default "r" (radial or horizonal) and z (height parallel to the axis). Here is a figure (from the internet) that shows what I think Chong means by cyclic symmetry. A symmetry condition is free in the plane and fixed in the out-of-plane direction. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or When we use the term CAD geometry, we are referring to a set of data structures that provide a very precise method for describing the shapes of parts. When working with geometries, the label of the geometry object will be displayed instead of the domain, boundary, edge, or point number. The other line of symmetry (x=0) has now ALSO been mirrored to run along the entire y-axis! Thus, when this is mirrored, you have the entire unit cell represented. It is also beneficial regardless of the phase See more By using symmetries in a model you can reduce its size by half or more, making this an efficient tool for solving large problems. The generally used terms In COMSOL Multiphysics ®, you can create 2D models from 3D geometries by using work planes along with the Cross Section Geometry operation. Then select to "Partition with:" Work Plane and select your work plane. The Cyclic symmetry is a special case of a Floquet condition, By default this node contains the selection that COMSOL Multiphysics has This section is available in 2D and 2D axial symmetry. The first 2 simulations are easily done using the coil geometry analysis node (and ensuing the length factor is given as 2 for the single plane symmetry version, so that the coil resistance is calculated correctly). My fiber has a numeric port on one end and a small opening at the other. The result is that the deformed geometry has no continuity in symmetry plane. Sincerely Ivar Simply define a work plane that slices your geometry across the symmetry plane: (Right-click on Geometry and select Work Plane. 4 with two different materials: one isotropic and the other anisotropic. From the Specify list, choose Position (the default) (Show in instances if in a geometry part, Show in 3D if in a work plane’s plane geometry) list: All levels, Domain selection, Boundary selection, Edge selection, or Point selection. This enables you to extract a cross section from your geometry and create a 2D model based on your 3D model, significantly reducing the Geometry models can be created within the COMSOL Multiphysics ® software environment using the built-in geometry modeling features and functionality. e. In a previous blog entry, we showed you how to model rotating machines, like motors and generators, using the Rotating Machinery, Magnetic interface in COMSOL Multiphysics. mph). Let us now see how we can use this geometric symmetry as well as our knowledge of the magnetic field and what direction the current is flowing to reduce the size of our modeling domain. In this regime, it is only necessary to refine the mesh sufficiently to give good resolution of the geometry. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or 3) If in doubt: use the Forum and COMSOL Support 🙂. In the COMSOL Multiphysics Reference Manual: The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The Floquet periodicity can be used for frequency domain problems with a spatial periodicity of the geometry and solution. The simplified geometry is a multilayer (only the green part) composed of layers of different materials and thickness, and four strips A (=C) and B (=D) jointed on top and at the bottom of it. It is also possible to include the dependent variable v for the out-of-plane The Magnetic Insulation boundary condition in COMSOL Multiphysics ® imposes symmetry on the sides. would prefer using a 3D simulation because I use Solidworks for modeling and the LiveLink for Solidworks to make quick geometry changes. The COMSOL Geometry models can be created within the COMSOL Multiphysics ® software environment using the built-in geometry modeling features and functionality. Specify the centerpoint of the scaling by specifying x, y, and(3D only) z; r and z in 2D axial symmetry; xw and yw in work planes. The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. When I analyse temperature or distribution for pipe flow in 2D axial symmetry mode, should I draw all geometry (complete diameter) or draw the half of it (radius size). These include the creation of a block or spheres, Boolean unions, intersections, or more high-level operations, such as The COMSOL terminology for geometry similarly follows this: For a 3D geometry, a solid volume enclosed by surfaces forms a domain, a surface area enclosed by edges forms a boundary, and a curve enclosed by points forms an edge. The direction of the angle θ can be This modeling domain has three planes of symmetry, i. I suspect that this is a result of meshing. The Symmetry Plane node adds a boundary condition that represents symmetry in the geometry and in the loads. Then i have selected the half of the partioned geometry under the symmetry boundarie. This is useful when you need not only the Sector symmetry to reflect the geometry but also a symmetry plane to take into account an infinite baffle. Now that I see the results, I realize that the symmetry condition in Structural Mechanics only forces the normal displacements to the symmetry surface to be zero (n·u = 0), but not the rotations. You can use several of these operations to also control the mesh. After that i have selected under the boundaries in the physics menu the option symmetry. This is done by splitting and then removing one half of the geometry using the Partition Objects and Delete Entities operations, You can define symmetry planes in 3D where the geometry/physics/results will be mirrored across the plane. Also, when enabling Modify model However, when using comsol, I am finding even and odd modes which are asymmetric. The 2D axisymmetric implementation in COMSOL Multiphysics by default assumes independence of the azimuthal component of the displacement. SMHH . Use a Mirror 2D () dataset to extend a solution defined on one side of an axis to the other side of the axis. When a structure exhibits axial symmetry, use the axisymmetric physics interfaces. If the geometry is axisymmetric, there are variations in the radial (r) and vertical (z) direction only and not in the angular (θ) direction. Thanks. You must have symmetry in the fields themselves in order to employ a mirror symmetry condition. A demonstration is also given of how to chain together data sets to create the best custom visualization for your simulation. When a The combination of COMSOL ® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. This method is called boundary representation, An alternative in COMSOL Multiphysics software is to use Virtual Operations, which can keep the existing geometrical representations as a basis The User Defined Coil Geometry subnode is available for Coil if the Conductor model of the parent feature is Homogenized multi-turn and the Coil type is set to User defined. The two planes of symmetry bisects the coaxial lumped port, then I adjust the settings by multipling the impedance by for 4. These savings can be significant when working with large models and multiphysics models. Changing the space dimension from '2D' to The Shell-and-Tube Heat Exchanger tutorial model geometry (left). In this article, we will begin by focusing on sketching in 2D directly in the Anti-symmetry keeps the flux normal, but what moves away from one side point towards on the antisymmetric side. For axially symmetric geometries, a 2D axisymmetric model is sufficient. When applied to an edge (in the Membrane interface) the symmetry plane is formed by the normal to the boundary and the edge tangent. The default is As of COMSOL Multiphysics ® 6. By default, the x, y (r and z in 2D axial symmetry, xw and yw in work planes), and (in 3D) z expressions define the coordinates of points on the curve in the standard coordinate system. The Vibrations of an Impeller model, available for download from the Model Gallery, compares the results of the analysis of one section of the geometry with the results for the full impeller geometry. Dear COMSOL User, I am facing simillar problem, When I go to symmtery under the physics tab If you were to mirror over one line of symmetry (say, y=0), you have half a unit cell. Use a Mirror 3D () dataset to extend a solution defined on one side of a plane to the other side of a plane. Just a simple question: How can I mirror the results through a symmetry plane in comsol's post processing? I want to view the results in full domain instead of half of it. If rays are propagating in the void region outside of the selected domains, it is possible for the rays to enter the region where r < 0, even though no geometry is defined there. When the Number of sectors is odd or Rotation is selected as the Transformation (cyclic symmetry), also enter the Azimuthal mode number as an integer The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. You can then solve a 2D problem in the rz-plane instead of the full 3D model, which can save considerable memory and computation time. Additionally, you can split a geometry into its corresponding entities by using a Split operation. There is a different analysis procedure, mainly in solid mechanics, called cyclic symmetry for solving a rotationally symmetric structure under general (non-rotationally symmetric Technically, the Moving Mesh branch represents the spatial frame in the Model Builder tree. If the model does not have a geometry, for example when using imported meshes, use the alternative analysis method by The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The boundary conditions for the Geometry Analysis are specified using the Input and Output subnodes available with the node. COMSOL Multiphysics ® contains a plethora of geometry tools, operations, and other functionality that provide you with a number of ways to create the geometry for your model. I modeled a round diaphragm (a thin disk) in Comsol 4. In this article, we will begin by focusing on sketching in 2D directly in the Graphics window. Since the geometry is symmetric, only a single quadrant of the geometry needs to be included in the model, and it is possible to use symmetry boundary condition. It The Symmetry Plane node adds a boundary condition that represents symmetry in the geometry and in the loads. The concepts of sector I have been using the symmetry boundary condition for structural mechanics. The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. Such field can be an analytic expression or can be computed using, for example, a Curvilinear Coordinates I am simulating a TEM (Transverse electromagnetic) cell. Dear COMSOL User, I am facing simillar problem, When I go to symmtery under the physics tab The first has no symmetry, the second has a single plane of symmetry and the third has symmetry in 2 planes. The modeled structure is typically a unit cell of a repetitive structure. In the COMSOL The geometry that represents a quarter of the steam reformer is shown in Figure 1. Is there a way to obatin the same results through the 2D axial symmetry stress-strain mode? I am also trying to obtain the longitudinal vibration modes of a very long cylinder. To demonstrate, the element size within the wire is selected based on the wire perimeter, starting with an element size that is one To also make all or one of the types of resulting entities (domains, boundaries, edges, and points) that the resulting objects consist of available as selections in all applicable selection lists (in physics and materials settings, for example), choose an option from the Show in physics (Show in instances if in a geometry part; Show in 3D in a plane geometry under a work plane in a 3D The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. It imposes symmetry for magnetic fields. Many physics interfaces are While I’ve had some success with basic symmetry cases, I’m still struggling to correctly define rotational symmetry for my cross-section. Also, I do not know of any case where periodic boundary conditions would be appropriate to handle mirror symmetries. For information about the use of this study and its functionality, see the AC/DC Module User’s Guide. Two types of sym The model consists of a rotational symmetry (see full-model. This includes custom tools for Recall that the time harmonic ansatz in the COMSOL software assumes that the field components oscillate in time according to e^{j\omega t}, where \omega is the angular frequency. I find this type of symmetry more typically called rotational symmetry. Expanding Geometry. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The geometry must be of a type that can be transformed through the use of rotation or reflection (mirroring). See Axial symmetry is common for cylindrical and similar 3D geometries. Show in 3D if in a work plane’s plane geometry) list The Axial Symmetry condition only applies to straight boundaries that are both on the axis of symmetry and adjacent to a domain in the selection of the physics interface. These steps This tutorial shows how planes of symmetry can be used in a 3D model to reduce the finite element model size and make the simulation faster. Radial components of your fields must be zero on the symmetry axis, to avoid discontinuities. 1 Reply Last Post Jan 10, 2013, 4:01 p. Best regards Edgar Enter the center of the rotation in the x and y (for 2D); r and z (in 2D axial symmetry); and xw and yw in work plane fields. The geometry have two PMC (Perfect Magnetic Conductor) symmetry planes, so I simulate only the quarter of the geometry. You should set up your geometry on one side of the symmetry axis. and then click to convert them to a COMSOL kernel representation. ) Then, partition. Thanks, Amir-----ps. I have used the 2D plane strain mode to obtain the eigen frequencies of the radial and torsional modes of a circular 2D geometry. You can easily visualize the In many cases symmetry of the geometry and loads can be used to your advantage in modeling. This selection also enables the Keep original faces check box that controls if the original faces are kept in the revolved 3D geometry. Reducing the size of your model is advantageous because of the amount of computational time and memory that can be saved when solving the equations for your model. Enter the Coil length multiplication factor F L and Coil area multiplication factor F A (dimensionless integer numbers). This applies to the cases where the geometries and modeling Important steps in building this model include preparing the geometry, defining the symmetry plane, and expanding the results plots to visualize the entire modeling domain. We will then show how to edit with Sketch mode and how you can add Object Primitives directly to your geometry. This is the point that stays fixed during the scaling (that is, the point that the scaled geometry objects approach when the scale factor goes to zero). If you click the Full revolution button you get a full revolution. This The geometry analysis algorithm can determine the axis and direction only if there is a geometry in the model. planes about which the geometry is exactly mirrored. It is also possible to include the dependent variable v for the out-of-plane You can define symmetry planes in 3D where the geometry/physics/results will be mirrored across the plane. . I need help with making a symmetric mesh for a simple geometry. If I could add a wish, for COMSOL Multiphysics: get it ready once to allow us to enter directly full tensor math as well as for the postprocessing, this would gain time compared to now when we need to rewrite everything for real/imaginary and only scalar components one by one. When a To obtain the final 3D geometry, sketching the geometry in 2D before expanding it to 3D is particularly useful when working with geometry that exhibits a type of symmetry, such as being symmetric along an axis or rotationally symmetric. We will also define boundary selections for the inlets and outlets, symmetry boundaries, and the interfaces between the domains. Once you have made your 2d-axi geometry, if you want to see how it looks in 3D, try a draw-extrude (over full 360°), this will create a new 3D geometry with your full 3D The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. A Point at the intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined. Is that what you are referring to? This will result in 1/2 or 1/4 symmetry or maybe even 1/8 depending on how many symmetry planes you define. Despite experimenting with simpler models, I haven't been able to set it up properly in COMSOL. I have tried it like that. tjuxggiqygsyygyiihjflzhvebqrgexxkjjasswonzluelfmgnxdshmpdjmxzlabvgxkexks
Comsol symmetry geometry When the Include circumferential displacement check box is selected, many nodes in the Model Builder show additional user inputs, such as fields to apply loads in the azimuthal direction (right). They are selected from the More 2D Datasets and More 3D Datasets submenus. See Virtual Geometry and Mesh Control Operations for examples of how to use virtual geometry operations to remove a short edge and to ignore and collapse edges to prepare the geometry for efficient meshing. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. (Right-click on Geometry and select Boolean Operations>Partition) Add the object to partition to the list. In the 2D axisymmetric formulation, the angular dependence of the electric field is given by e^{-j m \phi} , where m is an integer that is specified by the user. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or Editing a 2D geometry in the Graphics window. Today, we will demonstrate the steps we outlined with a 3D generator model example, comparing our results with an analogous 2D model. The Geometry node in the model tree of the COMSOL Multiphysics simulation software contains an ordered sequence of geometry operations. The COMSOL Multiphysics ® software contains a plethora of geometry tools, operations, and other functionality that provide you with a number of ways to create the geometry for your model. From your image the way you have cut your domain it looks like you should have antisymmetry on some of the fluxes, even if you want symmetry on the geometry and shape. but later on I want to add other components on the geometry which do not have this symmetry, and The check boxes in the Axial Symmetry Approximation section enable circumferential displacements in 2D axisymmetric models (left). In the COMSOL Learn how to create a plot using the Mirror, Extrusion, and Sector Data Sets to visualize the results from a model with symmetry. Keep in mind that COMSOL recognizes symmetry through the physics, not the actual geometry. Dear all, sorry the continuous questions today! I am going to use symmetry for the geometry as in the picture I attached. This can be used to model some situations where you want a plane One of my fellow students modeled a rather complex geometry in Comsol 3. There is a different analysis procedure, mainly in solid mechanics, called cyclic symmetry for solving a rotationally symmetric structure under general (non-rotationally symmetric sounds like you can do it in 2D axial symmetry. Two types of symmetry boundary Using symmetry is one of the most effective ways to reduce the size of a model. That said, I wonder if you may be, at least in part, confusing symmetry in geometry with symmetry in the EM fields. In reality the eigenmodes are known to be perfectly symmetric/antisymmetric. In 3D components, the Planes intersection line can be set Along the x-axis, Along the y-axis, or Along the z-axis. Symmetries can often greatly reduce the size of a model and hence reduce the memory requirements and solution time. The Perfect Electric Conductor boundary condition sets the tangential component of the electric field to zero. I’m performing a linear buckling analysis, and my geometry has a three-fold (120°) rotational symmetry. m. Can COMSOL solve for these modes? While I’ve had some success with basic symmetry cases, I’m still struggling to correctly define rotational symmetry for my cross-section. My problem is that the mode index and the e-field distribution at the port side i find with respectively the boundary mode analysis and the frequency domain study How should I plot 1d curves or 2d surfaces by symmetry? Dr Koslover in a 3d half model, mirror data 3d can be used to plot 3d stuff. The symmetry plane is formed by the normal to the membrane surface and the edge tangent. For the latter I will need to explore different crystal cuts, therefore I defined a rotated system for the material. Rotation and reflection are only available when using an even number of sectors. It is, however, possible to change this using the settings in the Position, Axis (3D only), and Rotation Angle sections. This tutorial shows how planes of symmetry can be used in a 3D model to reduce the finite element model size and make the simulation faster. But when plotting 1d curves or 2d surfaces, mirror data 2d doesn't seem to work and there's no mirror data 1d even. It controls the sign of the flux. When creating a model, one of the first steps you must take is to build the geometry. The position of the point along the intersection line can be arbitrary as it does not change the planes definition. 0, you can hover your mouse over geometry in the Graphics window and the associated geometry label will automatically be displayed on the left side of the Graphics window. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The model geometry for a flange is partitioned using a block as the tool object (left) in order to reduce the flange to a quarter (right). The options for the Symmetry type setting for the Symmetry Plane boundary condition. Enter a point on the rotation axis in the x, Show in 3D if in a work plane’s plane geometry) list: All levels, Domain selection, Boundary selection, Edge selection, or Point selection. This is useful if you have created a parametric curve with the right shape but The Shell-and-Tube Heat Exchanger tutorial model geometry (left). Unfortunately the space dimension should be solved in a cylindrical 2D dimension. Therefore, the physical components of the radial and axial displacement, u and w, are used by default as dependent variables for the axially symmetric geometry. I have built my geometry, then i took a workplane and use the partion object function. This can be useful for visualization of a solution to an axisymmetric problem. Does In many cases symmetry of the geometry and loads can be used to your advantage in modeling. Figure 1: The Well, you need to build only half the geometry (or build the entire geometry and then delete 1/2 of it). The Magnetic Insulation Boundary Condition The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. I draw a rectangle which has a heigth of pipe radia (not dia), and draw another rectangle on the first rectangle having a height of pipe wall thickness. Neither has COMSOL allowed to define a "cut plane" for a 3D geometry to export a projection as a 2D geometry to be used in 2D or 2Daxi The Geometry Analysis subnode to the Coil feature automatically appears to set up the automatic computation of the current flow in the coil. Normal Direction Condition. The COMSOL Multiphysics UI showing the Model Builder with the Coil feature selected, the corresponding Settings window, and the dynamic speaker model in the Graphics window. This includes custom tools for building certain kinds of geometries, such as those exhibiting a type of Here is a figure (from the internet) that shows what I think Chong means by cyclic symmetry. This Next, using the geometry from the shell-and-tube heat exchanger tutorial model, we demonstrate exploiting the symmetry of an object to simplify a simulation. For each of the regions shown in the figure we will set up selections that contain the corresponding domains in the geometry. In many cases symmetry of the geometry and loads can be used to your advantage in modeling. The design and physics are symmetric along the XZ-plane, enabling us to simplify the geometry by removing half (right). Specify in this feature an arbitrary vector field that defines the direction of the wires in the coil. Then, under the Physics set-up, right-click and define a symmetry boundary The 2D axisymmetric implementation in COMSOL Multiphysics by default assumes independence of the azimuthal component of the displacement. This node is available only in 2D axisymmetry, where the only possible symmetry plane is normal to the Z-axis. 5 in a cartesian 2D geometry. This is Chapter 2 of 3 in an Advanced If the model represents only a part of a geometry obtained from symmetry cuts (for example, a quarter of a circle), use the settings under Symmetry specification to specify appropriate correction factors. In Part 2 of the course, we cover how to expand a 2D geometry into 3D using a variety of the built-in operations in COMSOL Multiphysics ®. Because of the large size of my geometry and the symmetry of the problem I use the 2D axisymmetric settings. The corresponding 3D geometry results from a revolution around the z-axis. Point on Axis of Rotation . You can allow a symmetry plane to move along its normal direction. EST. This is visualized in the table below for clarity, using an example of a viscoelastic damper. It is a 2D axisymmetric problem and the geometry is a half circle. When I apply the meshing, it always give finer mesh for upper half part of the geometry while I need a symmetric meshing for lower and upper part and finer mesh around the center. Click the Angles button to specify the start angle (default: 0 degrees) and end angle (default value: 360 degrees; that is, a full revolution) of the revolution. Is it the same like to draw or build only the half geometry. Its Equation View subnode displays all contributions to the spatial frame deformation, for example the mesh smoothing equations used by a Deforming Domain feature, or the boundary motion implicitly prescribed by a Solid Mechanics interface. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or 2D-axi means you have cut your cylindrical symmetry cases along a (work)plane of dimension by default "r" (radial or horizonal) and z (height parallel to the axis). Here is a figure (from the internet) that shows what I think Chong means by cyclic symmetry. A symmetry condition is free in the plane and fixed in the out-of-plane direction. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or When we use the term CAD geometry, we are referring to a set of data structures that provide a very precise method for describing the shapes of parts. When working with geometries, the label of the geometry object will be displayed instead of the domain, boundary, edge, or point number. The other line of symmetry (x=0) has now ALSO been mirrored to run along the entire y-axis! Thus, when this is mirrored, you have the entire unit cell represented. It is also beneficial regardless of the phase See more By using symmetries in a model you can reduce its size by half or more, making this an efficient tool for solving large problems. The generally used terms In COMSOL Multiphysics ®, you can create 2D models from 3D geometries by using work planes along with the Cross Section Geometry operation. Then select to "Partition with:" Work Plane and select your work plane. The Cyclic symmetry is a special case of a Floquet condition, By default this node contains the selection that COMSOL Multiphysics has This section is available in 2D and 2D axial symmetry. The first 2 simulations are easily done using the coil geometry analysis node (and ensuing the length factor is given as 2 for the single plane symmetry version, so that the coil resistance is calculated correctly). My fiber has a numeric port on one end and a small opening at the other. The result is that the deformed geometry has no continuity in symmetry plane. Sincerely Ivar Simply define a work plane that slices your geometry across the symmetry plane: (Right-click on Geometry and select Work Plane. 4 with two different materials: one isotropic and the other anisotropic. From the Specify list, choose Position (the default) (Show in instances if in a geometry part, Show in 3D if in a work plane’s plane geometry) list: All levels, Domain selection, Boundary selection, Edge selection, or Point selection. This enables you to extract a cross section from your geometry and create a 2D model based on your 3D model, significantly reducing the Geometry models can be created within the COMSOL Multiphysics ® software environment using the built-in geometry modeling features and functionality. e. In a previous blog entry, we showed you how to model rotating machines, like motors and generators, using the Rotating Machinery, Magnetic interface in COMSOL Multiphysics. mph). Let us now see how we can use this geometric symmetry as well as our knowledge of the magnetic field and what direction the current is flowing to reduce the size of our modeling domain. In this regime, it is only necessary to refine the mesh sufficiently to give good resolution of the geometry. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or 3) If in doubt: use the Forum and COMSOL Support 🙂. In the COMSOL Multiphysics Reference Manual: The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The Floquet periodicity can be used for frequency domain problems with a spatial periodicity of the geometry and solution. The simplified geometry is a multilayer (only the green part) composed of layers of different materials and thickness, and four strips A (=C) and B (=D) jointed on top and at the bottom of it. It is also possible to include the dependent variable v for the out-of-plane The Magnetic Insulation boundary condition in COMSOL Multiphysics ® imposes symmetry on the sides. would prefer using a 3D simulation because I use Solidworks for modeling and the LiveLink for Solidworks to make quick geometry changes. The COMSOL Geometry models can be created within the COMSOL Multiphysics ® software environment using the built-in geometry modeling features and functionality. Specify the centerpoint of the scaling by specifying x, y, and(3D only) z; r and z in 2D axial symmetry; xw and yw in work planes. The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. When I analyse temperature or distribution for pipe flow in 2D axial symmetry mode, should I draw all geometry (complete diameter) or draw the half of it (radius size). These include the creation of a block or spheres, Boolean unions, intersections, or more high-level operations, such as The COMSOL terminology for geometry similarly follows this: For a 3D geometry, a solid volume enclosed by surfaces forms a domain, a surface area enclosed by edges forms a boundary, and a curve enclosed by points forms an edge. The direction of the angle θ can be This modeling domain has three planes of symmetry, i. I suspect that this is a result of meshing. The Symmetry Plane node adds a boundary condition that represents symmetry in the geometry and in the loads. Then i have selected the half of the partioned geometry under the symmetry boundarie. This is useful when you need not only the Sector symmetry to reflect the geometry but also a symmetry plane to take into account an infinite baffle. Now that I see the results, I realize that the symmetry condition in Structural Mechanics only forces the normal displacements to the symmetry surface to be zero (n·u = 0), but not the rotations. You can use several of these operations to also control the mesh. After that i have selected under the boundaries in the physics menu the option symmetry. This is done by splitting and then removing one half of the geometry using the Partition Objects and Delete Entities operations, You can define symmetry planes in 3D where the geometry/physics/results will be mirrored across the plane. Also, when enabling Modify model However, when using comsol, I am finding even and odd modes which are asymmetric. The 2D axisymmetric implementation in COMSOL Multiphysics by default assumes independence of the azimuthal component of the displacement. SMHH . Use a Mirror 2D () dataset to extend a solution defined on one side of an axis to the other side of the axis. When a structure exhibits axial symmetry, use the axisymmetric physics interfaces. If the geometry is axisymmetric, there are variations in the radial (r) and vertical (z) direction only and not in the angular (θ) direction. Thanks. You must have symmetry in the fields themselves in order to employ a mirror symmetry condition. A demonstration is also given of how to chain together data sets to create the best custom visualization for your simulation. When a The combination of COMSOL ® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. This method is called boundary representation, An alternative in COMSOL Multiphysics software is to use Virtual Operations, which can keep the existing geometrical representations as a basis The User Defined Coil Geometry subnode is available for Coil if the Conductor model of the parent feature is Homogenized multi-turn and the Coil type is set to User defined. The two planes of symmetry bisects the coaxial lumped port, then I adjust the settings by multipling the impedance by for 4. These savings can be significant when working with large models and multiphysics models. Changing the space dimension from '2D' to The Shell-and-Tube Heat Exchanger tutorial model geometry (left). In this article, we will begin by focusing on sketching in 2D directly in the Anti-symmetry keeps the flux normal, but what moves away from one side point towards on the antisymmetric side. For axially symmetric geometries, a 2D axisymmetric model is sufficient. When applied to an edge (in the Membrane interface) the symmetry plane is formed by the normal to the boundary and the edge tangent. The default is As of COMSOL Multiphysics ® 6. By default, the x, y (r and z in 2D axial symmetry, xw and yw in work planes), and (in 3D) z expressions define the coordinates of points on the curve in the standard coordinate system. The Vibrations of an Impeller model, available for download from the Model Gallery, compares the results of the analysis of one section of the geometry with the results for the full impeller geometry. Dear COMSOL User, I am facing simillar problem, When I go to symmtery under the physics tab If you were to mirror over one line of symmetry (say, y=0), you have half a unit cell. Use a Mirror 3D () dataset to extend a solution defined on one side of a plane to the other side of a plane. Just a simple question: How can I mirror the results through a symmetry plane in comsol's post processing? I want to view the results in full domain instead of half of it. If rays are propagating in the void region outside of the selected domains, it is possible for the rays to enter the region where r < 0, even though no geometry is defined there. When the Number of sectors is odd or Rotation is selected as the Transformation (cyclic symmetry), also enter the Azimuthal mode number as an integer The geometry selection for the PEC (left) and PMC (right) conductor boundaries to exploit symmetries in the model. You can then solve a 2D problem in the rz-plane instead of the full 3D model, which can save considerable memory and computation time. Additionally, you can split a geometry into its corresponding entities by using a Split operation. There is a different analysis procedure, mainly in solid mechanics, called cyclic symmetry for solving a rotationally symmetric structure under general (non-rotationally symmetric Technically, the Moving Mesh branch represents the spatial frame in the Model Builder tree. If the model does not have a geometry, for example when using imported meshes, use the alternative analysis method by The Shell-and-Tube Heat Exchanger tutorial model geometry (left). The boundary conditions for the Geometry Analysis are specified using the Input and Output subnodes available with the node. COMSOL Multiphysics ® contains a plethora of geometry tools, operations, and other functionality that provide you with a number of ways to create the geometry for your model. I modeled a round diaphragm (a thin disk) in Comsol 4. In this article, we will begin by focusing on sketching in 2D directly in the Graphics window. Since the geometry is symmetric, only a single quadrant of the geometry needs to be included in the model, and it is possible to use symmetry boundary condition. It The Symmetry Plane node adds a boundary condition that represents symmetry in the geometry and in the loads. The concepts of sector I have been using the symmetry boundary condition for structural mechanics. The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. Such field can be an analytic expression or can be computed using, for example, a Curvilinear Coordinates I am simulating a TEM (Transverse electromagnetic) cell. Dear COMSOL User, I am facing simillar problem, When I go to symmtery under the physics tab The first has no symmetry, the second has a single plane of symmetry and the third has symmetry in 2 planes. The modeled structure is typically a unit cell of a repetitive structure. In the COMSOL The geometry that represents a quarter of the steam reformer is shown in Figure 1. Is there a way to obatin the same results through the 2D axial symmetry stress-strain mode? I am also trying to obtain the longitudinal vibration modes of a very long cylinder. To demonstrate, the element size within the wire is selected based on the wire perimeter, starting with an element size that is one To also make all or one of the types of resulting entities (domains, boundaries, edges, and points) that the resulting objects consist of available as selections in all applicable selection lists (in physics and materials settings, for example), choose an option from the Show in physics (Show in instances if in a geometry part; Show in 3D in a plane geometry under a work plane in a 3D The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. It imposes symmetry for magnetic fields. Many physics interfaces are While I’ve had some success with basic symmetry cases, I’m still struggling to correctly define rotational symmetry for my cross-section. Also, I do not know of any case where periodic boundary conditions would be appropriate to handle mirror symmetries. For information about the use of this study and its functionality, see the AC/DC Module User’s Guide. Two types of sym The model consists of a rotational symmetry (see full-model. This includes custom tools for Recall that the time harmonic ansatz in the COMSOL software assumes that the field components oscillate in time according to e^{j\omega t}, where \omega is the angular frequency. I find this type of symmetry more typically called rotational symmetry. Expanding Geometry. To take advantage of symmetry planes and symmetry lines, all of the geometry, material properties, and boundary conditions must be symmetric, and any loads or sources must be symmetric or The geometry must be of a type that can be transformed through the use of rotation or reflection (mirroring). See Axial symmetry is common for cylindrical and similar 3D geometries. Show in 3D if in a work plane’s plane geometry) list The Axial Symmetry condition only applies to straight boundaries that are both on the axis of symmetry and adjacent to a domain in the selection of the physics interface. These steps This tutorial shows how planes of symmetry can be used in a 3D model to reduce the finite element model size and make the simulation faster. Radial components of your fields must be zero on the symmetry axis, to avoid discontinuities. 1 Reply Last Post Jan 10, 2013, 4:01 p. Best regards Edgar Enter the center of the rotation in the x and y (for 2D); r and z (in 2D axial symmetry); and xw and yw in work plane fields. The geometry have two PMC (Perfect Magnetic Conductor) symmetry planes, so I simulate only the quarter of the geometry. You should set up your geometry on one side of the symmetry axis. and then click to convert them to a COMSOL kernel representation. ) Then, partition. Thanks, Amir-----ps. I have used the 2D plane strain mode to obtain the eigen frequencies of the radial and torsional modes of a circular 2D geometry. You can easily visualize the In many cases symmetry of the geometry and loads can be used to your advantage in modeling. This selection also enables the Keep original faces check box that controls if the original faces are kept in the revolved 3D geometry. Reducing the size of your model is advantageous because of the amount of computational time and memory that can be saved when solving the equations for your model. Enter the Coil length multiplication factor F L and Coil area multiplication factor F A (dimensionless integer numbers). This applies to the cases where the geometries and modeling Important steps in building this model include preparing the geometry, defining the symmetry plane, and expanding the results plots to visualize the entire modeling domain. We will then show how to edit with Sketch mode and how you can add Object Primitives directly to your geometry. This is the point that stays fixed during the scaling (that is, the point that the scaled geometry objects approach when the scale factor goes to zero). If you click the Full revolution button you get a full revolution. This The geometry analysis algorithm can determine the axis and direction only if there is a geometry in the model. planes about which the geometry is exactly mirrored. It is also possible to include the dependent variable v for the out-of-plane You can define symmetry planes in 3D where the geometry/physics/results will be mirrored across the plane. . I need help with making a symmetric mesh for a simple geometry. If I could add a wish, for COMSOL Multiphysics: get it ready once to allow us to enter directly full tensor math as well as for the postprocessing, this would gain time compared to now when we need to rewrite everything for real/imaginary and only scalar components one by one. When a To obtain the final 3D geometry, sketching the geometry in 2D before expanding it to 3D is particularly useful when working with geometry that exhibits a type of symmetry, such as being symmetric along an axis or rotationally symmetric. We will also define boundary selections for the inlets and outlets, symmetry boundaries, and the interfaces between the domains. Once you have made your 2d-axi geometry, if you want to see how it looks in 3D, try a draw-extrude (over full 360°), this will create a new 3D geometry with your full 3D The Symmetry node adds a boundary condition that represents symmetry in the geometry and in the loads. A Point at the intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined. Is that what you are referring to? This will result in 1/2 or 1/4 symmetry or maybe even 1/8 depending on how many symmetry planes you define. Despite experimenting with simpler models, I haven't been able to set it up properly in COMSOL. I have tried it like that. tjux ggi qygsy ygy iihjfl zhve bqrge xxkj jasswo nzluel fmgnx dshmpd jmxzla bvgxke xks