I would be very grateful if someone can help me with several issues. Comsol has a good user software interface which facilitates contact modeling. You can specify boundary conditions through constraint, thereby you can set as many as you need. Comsol defines a general mixed boundary condition as comsol ab, 2005a. Plasmonic propagation mode should be localized at the metaldielectric interface and decay exponentially away from interface. I want to know how to add floquet bloch periodic boundary condition in pde module. To implement a periodic boundary condition in femlab, go through the following steps. Using floquet periodicity to easily calculate dispersion. Problem with a boundary condition in comsol physics forums. Sep 03, 2018 in this video, we will learn how to simulate the unit cell of the metasurface. In this model a plane wave with a wavevector with nonzero x and zcomponent and polarisation in ydirection should be modelled. How to add floquet bloch periodic boundary condition in pde. How to set boundary conditions from parametric solver. This can be done using the rf or wave optics modules from the comsol product suite.
I am trying to generate transmission plot for a periodic phononic crystal and i am getting different result for each. Implementation of periodic boundary condition comsol. It means that top and bottom boundary condition in your geometry are not essential. I dont think you are restricted to only one boundary condition. In this video, we will learn how to simulate the unit cell of the metasurface. Another challenge is setting up good radiation conditions at both sides of the system. The floquet periodic boundary condition for solids is available, according to comsol product specification chart, in the acoustics, mems, and structural mechanics modules. Port boundary condition port bcs are very important and useful when working with total field. Dear comsol community, i am dealing with floquet type of periodic boundary conditions. I would recommend to model this in the frequency domain and then use the transfer function to predict the time domain behavior.
New inflow boundary condition based on known upstream conditions. Study of subwavelength gratings to understand their. However, to transform the problem of the infinite layered system to a finite problem through the fb boundary conditions, introduce artificial aspects due to the periodicity of the dependent. Modeling phononic band gap materials and structures comsol blog. I want to model an electromagnetic plane wave incident upon a periodic structure. Whereas, floquet periodic boundary condition is applied along x and y directions. On the other hand, your problem seems to fit acdc module in comsol. Even though there are four nodes in the mesh, only three unique dofs exist, and it can be readily seen that the trial function is now value periodic. A wire grating unit cell is modeled, where floquet boundary conditions define the periodicity. Simulation of metasurface unitcell comsol multiphysics.
The periodic boundary condition and pml question about comol 4. Most of the rf components, devices, and products you design are affected by some other branch of physics, whether it be heat. Rigorous coupledwave analysis rcwa is a semianalytical method in computational electromagnetics that is most typically applied to solve scattering from periodic dielectric structures. Hybrid boundaryelementfi niteelement method bemfem for magnetic fi eld analysis u u soft magnet material model of permanent magnets u u adaptive frequency sweep for highfrequency electromagnetics u u comsol server product 4. Sofar my implementation looks as shown below, where i calculate eigenmodes for the unit cell with outer edges held constant at u0.
In my study i am doing a simulation of a 2d flow, with the boundary conditions. Equation for floquet periodicity is h dst h srcexpj k r dst r src, where indices dst and src represent destination and source boundaries. You can analyze how multiple physics affect rf designs by using the comsol multiphysics software and the specialized addon rf module. This boundary condition is controlled by maximum height of ponding in the same manner as described for the specified flux boundary condition see above. Modeling phononic band gap materials and structures comsol. In the frequency domain you can use the floquet periodicity condition. In addition, it demonstrates the polarization dependent behaviour of such gratings. Oct 14, 2011 this functionality is important for periodic boundary condition applications with highaccuracy requirements such as cyclic symmetry for structural analysis and floquet boundary conditions for electromagnetic wave propagation.
Pmc can be seen as the special case for blochs boundary condition periodic boundary condition where the kvector is set to zero in the corresponding direction. Wave optics software for analyzing micro and nanooptical. The metasurface is the twodimensional analogue of the metamaterial. The use of comsol for integrated hydrological modeling.
However, i dont know how to setup periodic blochfloquet boundary conditions so that i can loop over a set of kx and ky wavevectors. Exploiting symmetries while using floquet boundary conditions. Hello esteemed colleagues, in periodic boundary condition what is the difference between floquet periodicity and continuity type. This periodicity can be continuous the default or antiperiodic and can control which of the dependent variables that the periodic. Aug 30, 2018 the periodic condition node adds a periodic boundary condition.
The acoustics module is an addon to the comsol multiphysics software that provides tools for modeling acoustics and vibrations for applications such as speakers, mobile devices, microphones, mufflers, sensors, sonar, and flow meters. It is still possible to perform the analysis on a single sector. At the top and bottom boundary scattering boundary conditions are used in order to allow an excitation. Simulation software for analyzing acoustics and vibrations. 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. Floquet theory is a branch of the theory of ordinary differential equations relating to the class of solutions to periodic linear differential equations of the form. You can use the specialized features to visualize acoustic fields and build virtual prototypes of devices or. Modeling electromagnetic waves and periodic structures.
I am trying to simulate an infinite 2d triangular lattice in comsol but i am confused that how should i use periodic floquet boundary conditions on the unitcell. Pec line is the complement of pmc, so in figure 10, and figure 11, the pmc line will become the pec line if the wave polarization is changed to tm. Use for applying periodic boundary conditions with high accuracy requirements, such as cyclic symmetry in structural mechanics applications floquet boundary condition for electromagnetic wave propagation available for domains, faces and edges automatic orientation of source mesh on destination. Actually i cant select any surface when im trying to make the rotating interior wall boundary.
Using comsol multiphysics software, the eigenvalue problem equation can be solved by sweeping different values of and obtaining the corresponding values. If we add three new values in the window parameter value, comsol will start up a second resolution, ect but in our case, we would wish to associate a set of 1064 boundary conditions or less if we are able to group them by function. I have problem to chose element to set boundary condition. In periodic boundary condition what is the difference between floquet periodicity and continuity type. Comsol software users who are onsubscription should submit.
Use for applying periodic boundary conditions with high accuracy requirements, such as cyclic symmetry in structural mechanics applications floquet boundary condition for electromagnetic wave propagation available for domains, faces and edges automatic orientation of source mesh on. Feb 21, 2009 hi, im a chemical engineering student with a little problem with comsol multiphysics. The coefficients of transmission, reflection, and firstorder diffraction are also computed. The model developed uses an incident plane wave and floquet periodicity as a boundary condition to. An illustration that shows the imposition of periodic boundary conditions in 1d appears on page 11 in the paper uploaded here. For example, if you want a plane wave going only in the x direction, select floquet pbcs for the sides of the cube on the xaxis in the boundary mode. Periodic boundary condition in comsol can anyone help. This discussion is about an older version of the comsol multiphysics software. The periodic condition node adds a periodic boundary condition. Boundary conditions for triangular lattice in comsol. Using floquet periodicity to easily calculate dispersion curves and wave structures of homogeneous waveguides.
Finally, we mesh the structure, and we set the maximum mesh size in free space as 16 wavelength in electromagnetic waves setting. Modeling software for rf, microwave, and millimeterwave designs. This functionality is important for periodic boundary condition applications with highaccuracy requirements such as cyclic symmetry for structural analysis and floquet boundary conditions for electromagnetic wave propagation. Most of the rf components, devices, and products you design are affected by some other branch of physics, whether it be heat transfer, plasma, or structural mechanics, to name a few. This is a reduced version of the presentation without figures for the coil case. Jul 08, 2009 it sounds like you want floquet periodic boundary conditions pbcs for the sides from which the plane wave starts. The new features are available as copy domain, copy face, and copy edge. How to set boundary condition in adina for nastran file. Experiences from modeling very thin structures in comsol. Experiences from modeling very thin structures in comsol multiphysics bergen comsol user group workshop april 10th 20. Stiff boundary condition is a term borrowed from numerical solutions to differential equations. Floquetbloch theory and its application to the dispersion. Comsol software users who are onsubscription should submit their questions via the support center for a more comprehensive response from the technical support team.
Using periodic boundary conditions use periodic boundary conditions, periodic edge conditions, and periodic point conditions to define a constraint that makes two quantities equal on two different but usually equally shaped domains. Many nearly most with in engineering odes have smooth, continuous phase spaces the hypothetical space inhabited by solutions where numerical solvers dont have to make very tiny increments to their independent variable step size to come up with. The boundary conditions must then be based on floquet theory. Bloch floquet boundary conditions in weak form constraint.
The specified value is the total volumetric flow rate in units of l 3 t into the domain across a surface swept out by revolving the boundary segment 360 degrees about the z axis. I would impose periodic bc at the left and right boundaries. It is clear that this work only for plane waves, and that source and destination boundaries need to. However, this is not the correct approach, since there is a coupling between the fan blades. Mar 12, 2010 if we add three new values in the window parameter value, comsol will start up a second resolution, ect but in our case, we would wish to associate a set of 1064 boundary conditions or less if we are able to group them by function.
Pmcpec boundary conditions and plane wave simulation. Periodic blochfloquet boundary conditions for calculating. How to select rotating interior wall in comsol cfd. Now my question is when should i use the slit condition domainbacked or pecbacked and how can i define te or tm. It is a fourierspace method so devices and fields are represented as a sum of spatial harmonics. Now the question is how i should define the kvector to be used with a periodic floquet boundary condition in comsol. This software appears ideal for this application as it is capable of solving maxwells vectorial equations with appropriate boundary conditions. It is a class of periodic boundary conditions called floquet conditions, and they are very simple. And for the boundaries with a normal vector in xdirection floquet periodic condition are used. Mar 26, 2015 however, i dont know how to setup periodic bloch floquet boundary conditions so that i can loop over a set of kx and ky wavevectors. In such a boundary condition, an azimuthal mode number is introduced.
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