Comsol periodic boundary condition example. Regards Amit See full list on comsol.
Comsol periodic boundary condition example Oct 20, 2016 · I have tried floquat boundary condition but I get this warning. Feb 10, 2013 · Problems about Periodic Conditions in the tutorial model “Periodic Boundary Condition” Posted Feb 10, 2013, 12:10 p. This example shows the application of homogeneous and periodic boundary conditions to a periodic microstructure with varying sizes of the unit cell, illustrating the impact of these conditions on the resulting homogenized properties. A set of Magnetic Insulation boundary conditions on interior boundaries. The Periodic Flow Condition splits its selection into a source group and a destination group. This can be achieved by first meshing the source boundary or edge and then copying the mesh to the destination boundary or edge. Model Example: Permanent Magnet AC Generator For our purposes, we will focus on a sector of the permanent magnet generator tutorial , available in our Application Gallery. Does anyone have an example for me? Feb 16, 2015 · We will begin with an existing example from the COMSOL Multiphysics Model Library and modify it slightly to include a periodic heat load and the Events interface. That is, the Port boundary conditions each contribute to (as opposed to the Lumped Ports, which override) other boundary conditions. If I set periodic conditions with the type of continuity on a geometry of a cube, and then a prescribed displacement on a face, then the cube moves in space, but does not experience deformation because the displacement of 2 opposite faces is equal. m. Mar 27, 2018 · Periodic boundary condition. This blog post introduces the concepts behind this type of analysis and walks through the set-up of such problems. In this blog post, we will show how to simplify complicated numerical models using periodic boundary conditions with several examples from the RF Module Application Library. Errors during multiphysics. As an example, we can refer to the Frequency Selective Surface, Periodic Complementary Split Ring Resonator model, which is available in our Model Representative Volume Elements (RVE) for Homogenization of Periodic Materials. e. Various boundary conditions are employed in the computation of homogenized properties for heterogeneous materials. Add 'C' as an extra DOF using a Global Equations node (without equation). The Periodic Flow condition is used to set the velocity so it is identical at the inlet and outlet boundaries, allowing us to specify a pressure drop over a single unit cell. A pressure constraint at a single point is used to gauge fix the pressure field. The Periodic Condition node adds a periodic boundary condition that can be used to reduce the model size by using symmetries and periodicities in the geometry and physics interfaces being modeled. Jul 8, 2009 · I am using periodic boundary conditions see attached sim file I am attempting to create the band structure plots for a square lattice of circular cylinders in 2d. 6 Highlights (36:24) Updates to the Scattering Boundary Conditions (39:05) New Models II (40:40) Feb 18, 2016 · The concepts of sector symmetry and periodic boundary conditions, including examples illustrating their use, are also highlighted. The magnetic vector potential is solved for on The Periodic Condition node adds a periodic boundary condition. 0 is used for pure periodic or antiperiodic conditions. The Periodic Condition sets up a periodicity between the selected boundaries. Regards Amit See full list on comsol. Several different types of periodicity properties of the solution can be prescribed using this boundary condition. To add a periodic boundary condition, in the Model Builder , right-click a physics interface node and select Periodic Condition . Mar 9, 2015 · The Port boundary conditions are formulated slightly differently from the Lumped Port boundary conditions in that you can add multiple types of ports to the same boundary. I tried to solve it manually using Dirichet and Flux/Source, but the boundary condition is always overwritten by the other one. pdf for the SAW gas sensor p434 for V3. But z direction is open and also kz=0( no propagation). In built it's giving periodic flux boundary condition but I want periodic dirichlet condition. 1, we make a plane rectangle and solve the simplest of pde equations on it after applying periodic boundary conditions on the rectangle's two opposing edges. The Periodic Condition node defines periodicity or antiperiodicity between two boundaries. The usage of this condition is Apr 22, 2019 · If you address an entire periodic problem in a simulation, it involves a high computational cost and long computation time. For this I have used "Coefficient Form Boundary PDE". - Feature: Periodic Condition 2 (pc2) - Feature: Compile Equations: Frequency Domain (sol1/st1) I couldn't solve this problem. Effective density = integration(density*thickness)/V, where V = 17. The Periodic (boundary) condition allows for more general symmetry where both the current and the magnetic field vector can be at an angle to the boundary. The choice between periodic or homogeneous boundary conditions depends on whether the infinitesimal volume is modeled as a repeating unit cell (RUC) or a representative volume element (RVE). Mar 17, 2014 · The COMSOL software offers a predefined functionality available in the Solid Mechanics interface for setting up cyclic symmetry conditions (found under the Periodic Condition Boundary feature). Jul 14, 2014 · In such cases, the Periodic (boundary) condition may be appropriate. Dear sir, Thanks for your post. Feb 4, 2019 · There are some diffent approaches you could use, but the quickest is probably to edit the constraint expressions for the periodic boundary condition in Equation View. Nagi Elabbasi This condition is used to model infinite periodic structures with nonnormal incident pressure fields or excitations. Essentially these plots consist of listing the degenerate eigan solutions for the first brillouin zone i. Acoustics Module (1:39) Periodic Boundary Condition (7:13) Thermoviscous Boundary Layer Impedance Boundary Condition (9:51) Example Model: Sonic Crystal (11:50) Background and Motivation (12:24) Geometry and Setup (13:24) Analysis for Band Structure (13:51) Results (14:31) Live Demo (15:53) If more advanced periodic boundary conditions are required, for example, when there is a known rotation of the polarization from one boundary to another, see Component Couplings and Coupling Operators in the COMSOL Multiphysics Reference Manual for tools to define more general mappings between boundaries. This periodicity can be continuous (the default) so that u (x 0) = u (x 1) or antiperiodic so that u (x 0) = − u (x 1) and can control to which dependent variables the periodic condition applies. This condition is used to model infinite periodic structures with nonnormal incident pressure fields or excitations. Now I need a periodic boundary condition between two opposite edges. It is sufficient to span a relatively small range of wave vectors covering the edges of the so-called irreducible Brillouin zone (IBZ). I have defined periodic boundary condition for opposite faces (in y and z direction) and I have defined equal but with different sign prescribed displacement with 0 displacement in z and y direction for other two faces. Aug 6, 2014 · COMSOL Multiphysics, together with the RF Module, enables you to model a periodic complementary split ring resonator with ease by utilizing perfectly matched layers and periodic boundary conditions. Using Periodic Conditions to Simplify Your RF Models The Periodic Condition feature sets u i (x 0) = u i (x 1) for a displacement u i or similarly for the electric potential. In this blog post, we focus on homogenized material The Periodic Flow Condition splits its selection into a source group and a destination group. This example shows the application of homogeneous and periodic boundary conditions to a These boundary conditions are based on the Floquet theory which can be applied to the problem of small-amplitude vibrations of spatially periodic structures. To make sure that the periodic conditions couples the correct dependent variables on the two sides of the slit condition, multiple periodic conditions are defined— both in front of the port and behind the port. 32[mm] 50[mm] 15[mm]. For many types of inhomogeneous materials, it is possible to compute effective material data by studying the smallest repetitive structure by using periodic boundary conditions. Some Notes on Using Periodic Conditions. The Periodic Condition splits its selection in two groups: one source group and one destination group. I am trying to measure the Young modulus (E) of a SC unit of Solid and Air. The homogeneous boundary conditions should be used on an RVE subvolume, while the periodic boundary conditions are appropriate for an RUC subvolume. 4. Above the pyramid is a perfectly matched layer (PML) and the space This can be achieved by first meshing the source boundary or edge and then copying the mesh to the destination boundary or edge. This is accomplished in two steps: first by creating a mesh on only one of the boundaries and then using the Copy Face operation for the mesh on the other boundary. I would like to improve a Robin boundary condition where I know the equation for the interface temperature, which varies over time, as follows: Where: T_SS(t): The temperature of my mold, which varies over time. Example 1. When the Periodic Condition stretches across regions with a mix of default material models, PMLs, background pressure fields, or background acoustic fields, it is recommended to add one Periodic Condition for each set To add a periodic boundary condition, in the Model Builder, right-click a physics interface node and select Periodic Condition. For such a unit cell model, the walls of the channels are set to the Wall, No Slip condition. What will then determine the choice between RVE and RUC? When the microstructure of the material is truly periodic, periodic boundary conditions will give the most accurate results. EDT Low-Frequency Electromagnetics, Modeling Tools & Definitions, Results & Visualization Version 5. Jan 10, 2010 · For me it should be rather rather similar, you have an example (mixed physics) in the smemodlib. Jun 6, 2017 · The model includes Floquet periodic boundary conditions on the left and right sides of the modeling domain and a Port boundary condition at the top and bottom. My unit cell has periodic boundary condtion in x an dy direction . Jun 27, 2016 · In your post, does the Robin Boundary Condition look like: k*dT/dx=a*(T0-T)? I was trying to implement such a boundary condition in Comsol, but the result shows the convective heat flux is much different from the conductive heat flux. The Periodic boundary condition is applicable to the periodic materials and needs an RUC material subvolume. This works fine for cases like opposing parallel boundaries. To add a periodic boundary condition, in the Model Builder, right-click a physics interface node and select Periodic Condition. Such a cell is often called a representative volume element (RVE). Sep 6, 2018 · Help with Periodic Boundary Conditions. PST RF & Microwave Engineering 8 Replies If more advanced periodic boundary conditions are required, for example, when there is a known rotation of the polarization from one boundary to another, see Nonlocal Couplings and Coupling Operators in the COMSOL Multiphysics Reference Manual for tools to define more general mappings between boundaries. Dec 4, 2024 · FORUM Boundary condition & Periodic Boundary condition; KNOWLEDGE BASE My Flux Calculation Seems Wrong; BLOG Exploiting Symmetry to Simplify Magnetic Field Modeling; KNOWLEDGE BASE What to do when a linear stationary model is not solving; BLOG Using the Inflow Boundary Condition in Nonisothermal Flow Simulations Typically when a periodic boundary condition is used with a compressible flow, the pressure is the same at both boundaries and the flow is driven by a volume force. Aug 8, 2014 · COMSOL has a symmetry condition which you can apply to the boundaries on your symmetry plane. g. In this model a plane wave with a wave-vector with non-zero x- and z-component and polarisation in y-direction should be modelled. At the top and bottom boundary scattering boundary conditions are used in order to allow an excitation. This condition is used to model infinite periodic structures with non-normal incident pressure fields or excitations. Then modify the constraint and constraint force expressions in the periodicity condition to something like For periodic conditions on shells the periodicity condition acts on edges, as opposed to solids and plates where it acts on boundaries. wave is only propagating in x and y direction. There are several examples in the COMSOL Model Gallery on periodic structures (for example Model ID 1974). The Periodic Condition node can be used to define periodicity for the mass transport between two sets of boundaries. I would like to ask for your suggestion for my work. The Periodic Condition node adds a periodic boundary condition that can be used to reduce the model size by using symmetries and periodicities in the geometry and physics modeled. Use a Periodic Condition to prescribe that the displacements on two different sets of boundaries with the same geometrical shape are related, as in a periodic structure. If the problem is to determine the frequency response to a small-amplitude time-periodic excitation that also possesses spatial periodicity, the theory states that the solution can be Aug 24, 2015 · I suspect that when you add a periodic condition, you still need to restrain one point, or some other boundary to fully constrain the solution, and that could be the issue, that your solution is modulo a constant and that sometimes the numeric make COMSOL to manage to +/- converge to one possible solution, but then by changing the mesh or The Periodic Flow Condition splits its selection into a source group and a destination group. , the reciprocal lattice. The node prescribes continuity in the concentration and the mass flux between the “source” and the “destination” side, respectively. This periodicity makes the selected boundaries connected so that they are not walls, and the wall distance values are continuous across the periodic boundaries. 3 4 Replies This penetration is approximated by a boundary condition to avoid the need to include another domain in the model. 2a, Version 5. PDT 0 Replies . Dec 28, 2021 · Hi, I am working with a coefficient form pde in a rectangular domain. If more advanced periodic boundary conditions are required, for example, when there is a known rotation of the polarization from one boundary to another, see Nonlocal Couplings and Coupling Operators in the COMSOL Multiphysics Reference Manual for tools to define more general mappings between boundaries. . The default is zero. The boundary selection of a Periodic condition consists of a pair of boundary sets with an identical geometry shape, where we connect two surfaces with the following numerical conditions: In this case, it is a reasonable approximation, as long as the losses on the conductive material are not of interest. Fluid that leaves the domain through one of the destination boundaries enters the domain through the corresponding source boundary. Jul 31, 2024 · What Comsol options should I use to properly define periodic boundary conditions (PBCs) for solids with uniformly distributed cylindrical holes? Unit cell is presented in: (unit-cell-1, unit-cell-3) Some Comsol helps does not help to solve the problem of compressing / stretching the unit cell. If you still need help with COMSOL and have an on-subscription license, please visit May 21, 2012 · Actually yes this exactly means that the problem is now 1D. If required, activate periodic conditions on more than two boundaries, in which case the Periodic Condition tries to identify two separate surfaces that can each consist of several connected boundaries. Nov 12, 2021 · We are trying to reproduce the Periodic Boundary Condition by adding extra beams that are not part of the original geometry and they have a high cross section area and inertia moment, so when we define a coefficient of thermal expansionof 1 on those beams and we define a temerature of 294. 3) is selected for Compressibility under the Physical Model section for the physics interface. Sep 7, 2018 · For example, on one hand, the boundary conditions in a 1D problem are constraints at isolated points. 5a, But it also can not works in COMSOL 4. Jul 3, 2012 · Suppose, for example, that your boundary were simply a continuity condition (such as a non-physical "surface" in the middle of a problem, due to the way you built the geometry). Jul 22, 2016 · In am simulating plane waves incident upon a stack of thin films (at oblique angle of incidence), each layer with different (real part of) refractive index, e. The default coordinate system is May 7, 2014 · the periodic boundary conditions in 4. PDT Modeling Tools & Definitions, Parameters, Variables, & Functions Version 5. Periodic Condition 1 1 In the Physics toolbar, click Boundaries and choose Periodic Condition. A slit condition means that the dependent variable can have different values on the two sides of the boundary. Jan 17, 2014 · Both modules provide Floquet periodic boundary conditions and periodic ports and compute the reflected and transmitted diffraction orders as a function of incident angles and wavelength. In that case, both normal and tangential fields would automatically be continuous across it, without you having to specify that condition at all. On the other hand, a condition that should hold at every point is a distributed constraint. The Port boundary condition at the top launches a plane wave at a specified angle of incidence and computes the reflected light, while the one at the bottom calculates the transmitted light. The periodic boundary condition typically implements standard periodicity so that u (x 0) = u (x 1) (that is, the value of the solution is the same on the periodic boundaries). Expressions for the reinitialized particle velocity are evaluated at the source boundary, not the destination; for example, expressions in terms of tangential and normal vector components will use the directions tangent or normal to the May 14, 2015 · Anisuzzaman Boni August 2, 2017. 15K they produce an unitary themal expansion that May 21, 2020 · I need to apply a periodic boundary condition, but it affects my initial values when I use it. com Use periodic boundary conditions to make the solution equal on two different (but usually equally shaped) boundaries. I have come up with a few ideas: Use this node to add periodic temperature conditions to boundary pairs. Feb 15, 2012 · Hello everyone, I'm trying to solve a problem with periodic boundary conditions. Alternatively, the Impedance Boundary Condition models the boundary of a domain with finite conductivity. When the Periodic Condition stretches across regions with a mix of default material models, PMLs, background pressure fields, or background acoustic fields, it is recommended to add one Periodic Condition for each set Feb 10, 2016 · Evaluating the frequency response of a phononic crystal simply requires an analysis of the periodic unit cell, with Bloch periodic boundary conditions spanning a range of wave vectors. different k-vectors. Posted Mar 27, 2018, 5:09 a. Apr 22, 2019 · Right: The Periodic boundary condition generates an infinite array of the wire grating. 2 t t t Floquet Periodic Boundary Condition, example Air Air Glass Jun 26, 2021 · Greetings, I simulated a metamaterial absorber applying PEC condition in metallic parts,having periodic BCs everywhere and i also use two periodic ports(to calculate S11 and S21),pmls on the boundaries where the ports are to avoid extra order modes from existing and a scattering condition right under the receiving port. Failed to find destination boundaries or the destination selection is empty. Jul 9, 2014 · Below, you can see the infinite 2D array of the pyramidal structures. c for k,e and v are set to periodic however. Dec 10, 2012 · I have question regarding the boundary conditions used in the tutorial model about periodic boundary conditions. When the Periodic Condition stretches across regions with a mix of default material models, PMLs, background pressure fields, or background acoustic fields, it is recommended to add one Periodic Condition for each set I want to simulate a 3D nanowire by periodic boundary condition in COMSOL/ELECTROSTATICS mode for the first time. I have seen the manual describing the use of periodic boundary conditions in 3. The Periodic Condition node adds a periodic boundary condition. Expressions for the reinitialized particle velocity are evaluated at the source boundary, not the destination; for example, expressions in terms of tangential and normal vector components will use the directions tangent or normal to the If more advanced periodic boundary conditions are required, for example, when there is a known rotation of the polarization from one boundary to another, see Component Couplings and Coupling Operators in the COMSOL Multiphysics Reference Manual for tools to define more general mappings between boundaries. Jan 24, 2024 · It has two different boundary conditions, Periodic and Homogeneous. Integration is performed over the cell domains. This corresponds to a situation where the geometry is a periodic part of a larger geometry. What you outline can be done with a Model Coupling, found under Definitions. Use it to model, for example, a large perforated plate with an oblique incident wave with wave vector k (and set k F = k) by only analyzing one hole or one subset of holes that is periodic. What I did was setting q0=h(Text-T) as convective heat flux, I assume it should be equal to k*dT/dx at the Modeling Periodic Structures in COMSOL Multiphysics Wave Optics 5. The periodic boundary conditions are more “advanced”. In this case, if the Azimuth angle of incidence at the source port boundary is α 2, the Azimuth angle of incidence at the listener port boundary π/ 2 − α 2 and the signs of the diffraction order on the source and listener ports are opposite. You can use the rule of mixtures to find the effective density. Posted Mar 27, 2017, 8:08 p. Mar 27, 2017 · Implementing Periodic Boundary Conditions in Coefficient Form Boundary PDEs. The Periodic condition is used when all we know is that the solution must be periodic. 2 Select Boundary 12 only. The Port boundary conditions also specify The Periodic Condition node can be used to define periodicity for the mass transport between two sets of boundaries. Using Periodic Conditions to Simplify Your RF Models Aug 21, 2024 · I have tried Manually coupling for Periodic Boundary Condition by Pairs (Identity Point Pair) under Definitions node, it gave me a syntax (src2dst) which is a source point existence indicator it is used while applying the point constraint in the at destination point for periodic displacements as follows, src2dst_p1(u)*exp(-1i*kx*a) and src2dst Sep 22, 2012 · Hello Aimi Abass Your Discussion has gone 30 days without a reply. This feature works well for cases like opposing parallel boundaries. I want to impose a periodic boundary condition on the two opposite edges of the rectangle. Use Floquet-periodic conditions on all side boundaries. The Destination Selection subnode is available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu. This periodicity can be continuous (the default) or anti-periodic and can control which of the dependent variables that the The periodic condition can identify simple mappings on plane source and destination boundaries of equal shape. Electromagnetic Waves, Frequency Domain (emw) and choose the boundary condition Perfect Electric Conductor. There are three types of periodic conditions available (only the first two for transient analysis): Oct 21, 2024 · To find effective density you do not need periodic boundary conditions. This means that the orientation cannot be determined automatically. Typically when a periodic boundary condition is used with a compressible flow, the pressure is the same at both boundaries and the flow is driven by a volume force. Apr 22, 2019 · If you address an entire periodic problem in a simulation, it involves a high computational cost and long computation time. We will look at an example of the Laser Heating of a Silicon Wafer , where a laser is modeled as a distributed heat source moving back and forth across the surface of a spinning Sep 6, 2024 · Hello everyone. pdf" p257 (v3. Global constraints specify some norm (usually an integral) of the solution. Posted Sep 6, 2018, 9:35 p. 5(a) but they have used a Dirichilet boundary condition on temperature at the inlet while a convective flux at the exit the b. 5a). For nonperiodic materials, the Homogeneous boundary conditions can be applied with an RVE material subvolume. You must provide coordinate systems using the Orientation of Source and Orientation of Destination sections. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. The impeller geometry is divided into eight identical sections, as shown below. Do you know about any example that implements these boundary conditions with the semiconductor interface? Thank you Jose Santos. In other cases, right-click Periodic Condition and select Manual Destination Selection to control the destination. The structure can be modeled using Floquet-periodic boundary conditions on four sides, where one unit of the model contains the pyramidal structure as well as the block beneath it made of the same material. Use periodic boundary conditions to make the solution equal on two different (but usually equally shaped) boundaries. If two boundaries are selected COMSOL Multiphysics automatically assigns one boundary as the source and the other as the This condition is used to model infinite periodic structures with non-normal incident pressure fields or excitations. I follow the documentation dedicated to this topic, but it did not work. 5a, and some generic explanation in the chapter on "Using Periodic Boundary Conditions" in the "guide. Sep 19, 2012 · The unit cell has Floquet periodic boundary conditions [PBC], and I am doing a parametric sweep of the geometry features of the basis (the unit cell area doesn't change). 3 0 Replies Sep 13, 2023 · I would like to solve a mathematical problem on a surface in 3D. I am trying to find band diagram of a photonic crystal. By default it contains the selection that COMSOL Multiphysics identifies. You should use them if you have a periodic structure or cyclic symmetry. Boundary Selection The software usually automatically identifies the boundaries as either source boundaries or destination boundaries, as indicated in the selection list. See also Periodic for the angle definition. The destination can also be rotated with respect to the source. The problem is that when the geometry changes become large enough, for example when a feature cross the unit cell boundary on the left it would then appear on the right to COMSOL, Inc. The other quesiton is the PML can be defined in Structural Moudule in COMSOL 3. Now the question is how i should define the k-vector to be used with a periodic FLOQUET boundary condition in COMSOL. Although the equation is identical to the one in the low-reflecting boundary condition, it has a different interpretation. If more advanced periodic boundary conditions are required, for example, when there is a known rotation of the polarization from one boundary to another, see Component Couplings and Coupling Operators in the COMSOL Multiphysics Reference Manual for tools to define more general mappings between boundaries. Can anyone tell me how should I do that? I am using comsol 4. The material properties are for the domain outside the boundary and not inside, as for low-reflecting The periodic boundary condition requires identical surface meshes on paired boundaries. No input is required when Compressible flow (Ma<0. Dec 19, 2024 · I am working on a 1D model in the Heat Transfer in Solids (ht) module. If User defined is selected, enter values or expressions for the components of the Reinitialized particle velocity v r (SI unit: m/s). When the Periodic Condition stretches across regions with a mix of default material models, PMLs, background pressure fields, or background acoustic fields, it is recommended to add one Periodic Condition for each set Jan 13, 2015 · In fact, the problem is completely general! As per a model example given in the help in comsol 4. hlfm oieoi yydghhn binqu swbsw pfyia pacvkatd uubbm lrplt vafot