finding the magnetic field density in the center of a rectangular coil
I have built a rectangular coil on solidworks which I imported to comsol to use as a magnetic field source, but cannot get it to work. I selected mef for my physics and placed a terminal at the top of...
View ArticleDefining the applied voltage V as a function of time
Hi, I am Naveen doing my MS project "modeling of electrosorption" at Hindustan Unilever R&D,bangalore.In my problem i want to define V=0 at time t=0s and V=V0 at time t>0.Here +V0 is the applied...
View ArticleWhat's the difference between the "harmonic propagation" and "scattered...
Dear all: IN the RF => In plane wave model ,What's the difference between the "harmonic propagation" and "scattered harmonic propagation"? Q2. if I set the square and draw the rectangle around the...
View Articlempheval command
Dear all, I have got some questions regarding the mpheval command, which are not very clear in the documentation. There is a model file, that I export to matlab, that contains 2 studies, with a...
View ArticleUndefined value found in the equation residual vector.
I am trying to model a pem fuel cell. Although I have entered all parameters and values, i have some errors as follows; Undefined value found. - Detail: Undefined value found in the equation residual...
View ArticleBC convergence criterium or Stop condition
Hi to all, i'm trying to solve a problem of heat transfer in porous medium in non local thermal equilibrium. I use 2 ht modules linked by a source term to compute fluid and solid phase equations. This...
View ArticleHow to save a 3.5a file in a 3.3 version ?
Hi, I have created *.mph models with the 3.5a version. For my PhD, I am in collaboration with an other laboratory working with the 3.3 version of COMSOL. But, they can't open my model. So, how I can...
View Articleaccessing MATLAB global variables when running models in MATLAB
I have defined an external function in matlab that I use in my Comsol/Matlab livelink model to set a volume heat source, let's call this function my_heat(x,y,z), where x,y,z are comsol spatial...
View ArticleHow to Couple Free and Porous Media Flow with Heat Transfer In Solids
Hi Everyone, I am new to COMSOL and I am trying to simulate a solar panel cooling system. I am trying to simulate in 2D the heat transfer between a thin rectangular layer (the photovoltaic cell),...
View ArticleExtracting .mph files from recovery files folder
I am running Comsol 4.2 on Linux cluster. Comsol saves the recovery files in a specified directory (using option -recoverydir <path>) which saves data till last time step. However it is not in...
View Articledefine velocity boundary condition at membrane surface
Hi, I need to define velocity boundary condition at the surface of membrane that is permeable. do you have any suggestion? Thank you.
View ArticleHigh heat flux not computing
Hi all, I’m trying to simulate laser heating of a sample and I’m struggling with a evaporation heat flux away from the sample surface. Whenever I do so there is a region underneath the surface where...
View Articlemodeling of turbulent flow in pipe and annulus. (pipe has porous wall)
Hi, I am trying to model turbulent flow in a pipe and annulus and find the pressure and velocity distributions. The flow is going to the pipe and is coming back from the annulus. The pipe has porous...
View Articleacoustic
i would like to model a flute. i am trying a simple open pipe with one end acting as source combined output from all holes. i dont even have an idea which physics to chose. can anyone briefly lay out...
View Articleregarding hydrogen value
Hello I am developing SAW sensor with 3-D nanowire sensor array. Here i used lithium niobate as piezoelectric substrate. ZnO as layer. It asks matrix value for all. I given all values. there is no...
View ArticleDividing two angles; still has unit
Hi, I have a simple problem. In my parameter list I divide two angles by each other. alpha = 45 [°] delta_alpha = 0.01 [°] number = alpha/delta_alpha What I get is n is 2000.0 rad. This causes some...
View ArticleHeat transfer coefficient
hi everyone there is an example in the comsol microresister_beam,in the example there is a Heat transfer coefficient k,why k is 5[W/(m^2*K)],but in the example Thermal Microactuator there is also a...
View ArticleHow to generate a network model in COMSOL?
Hi Is there anyone who is working in Pore-scale network modeling using COMSOL? Please let me know. Thanks
View ArticleUse a solution of a very similar problem as initial values...
Dear all, I am generating a phononic band diagram of a photonic crystal (mechanics-analogy to photonic bands...) by sweeping the bloch-floquet k vector from Matlab (i.e. a boundary condition - but in...
View ArticleInternal stress does not affect mechanical eigenvalues.
Hello, I am trying to use "Initial Stress and Strain" in Solid Mechanics to tune the mechanical frequency of a (doubly-clamped) micro-beam. I am trying to use "Pre-stressed Eigenfrequency Analysis"...
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