Convergence, time-dependent study
Hi everyone, I'm doing a time-dependent with phase inicialization study of Laminar two-phase flow, level set.. As you can see in the attach file the reciprocal of step size is increasing (very slowly)...
View Articleapply a limiter function for the solution in time-depedent simulation
hi, dea all, I have such a question. I have a one variable time-dependent problem, let's say the variable is T. 'T' is meaningful when it is below a threshold value, 'Tmax'. When 'T' is larger than...
View ArticleCreate Diagram of progress of additional variables like forces during solving...
Dear COMSOL Users, I am new using COMSOL CFD-Module but made experience with CFD Software like ANSYS CFD or OpenFOAM in my past. Most times I use CFD to calculate flow and forces in valves. The...
View ArticleHow can I couple 2 temperatures in different physics!?
Hi How can I couple 2 temperatures in different physics!? I have laminar flow and heat transfer in fluids Modules and one extra PDE Eqn. I want to have the same Temperature in both PDE and Heat...
View ArticleUpper and Lower Constraints or limits on variables
I have a model I am trying to run involving the concentration of hydrogen in zirconium and it keeps dropping below 0 in some spots and above 1 in others... It solves several PDE's one of which is the...
View Articletime dependent study
I am trying to model a countercurrent shell and tube heat exchanger like geometry that involves heat tranfer coupling and also reactions. I am getting the results for steady state simulation but when i...
View ArticleEquation in matrix form for use for MATLAB Livelink
Dear all, This seems to be a pretty simple question but I am struggling to find any help on the topic! I have recently started using COMSOL with the livelink to write a Model Order Reduction in MATLAB....
View ArticleCalculate base pressure of Ahmed body
Hi everyone , I was working on the Ahmed body example available in the website. Does anybody have an idea on how to calculate base pressure at the back the body? Thank you. Best Regards, Sachet
View ArticleSetting up 3-d Navier-Stokes using weak form pde
Hello, I am trying to set up 3-D navier-stokes equation for a fluid confined in a box, using weak form PDE , instead of the comsol predefined fluid flow module. I eventually want to make one of the...
View ArticleCalculation time
Hello, I developed a model which simulate the trajectories of atmospheric particles in an electrostatic precipitator. In order to optimize the collection efficiency, I plan to run the model by changing...
View ArticleFloquet boundary conditions in multilayer structure.
Hi all, I am trying to simulate a multi junction solar cell (for eg: Si/SiO2/Al) and trying to study the electromagnetic behavior of it. For periodic conditions I had used floquet boundary conditions,...
View ArticleUndefined Variable with structured grid
Hi all, I am a new user of COMSOL. I am trying to implement a vector transport equation with Discontinuous Galkerkin FEM method. When I used free tetrahedral meshes the simulator works fine. However,...
View ArticleSeveral parameters in fixed solution is not supported
I'm receiving the above error while computing a particle tracing study. I have three studies: 1 stationary stokes flow, 2: parametric sweep (2 variables) stationary electric currents, and 3 time...
View ArticlePoisson-continuity coupled equation
Hello, I try to model the corona discharge in wire-cylinder geometry governed by the equations: nabla (V) =- rho/epsilon0 (Poisson equation) and grad (rho) * grad (V) = rho ^ 2/epsilon0 (equation of...
View Articleimpedance of a piezoelectric
How do I calculate the impedance of a piezoelectric element? I am using 2D-axisymmetric (space dimension): piezoeletric diveces (pzt) modes with study: frequency domain.
View Articlemodelling gravity anomaly - geophysics
Dear all, I'm setting a simple model about the gravity anomaly induced at surface by a denser rod below ground level. I've to solve the Poisson Equation for the gravitational potential. I've selected a...
View ArticleBoundary layer meshing error
Hi, I would really appreciate if somedbody could help. Well i am doing flow simulation similar to Ahmed body example of COMSOL. One of the 1st problem is the boundary layer meshing. I did follow the...
View Articleweak constraint or pointwise constraint
Hello, I would like to have ur opinion for this situation: I wish to constraint the (fluctuating) pressure to an average value of 20 [constraint expression: aveop1(p)-20] at the inlet boundary while...
View ArticleFourier transform
Hello everybody, In my project I have a current density J as a result of my studio, which is different from zero only in a little time interval. Now I want to calculate its Fourier transform in order...
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