how can set up the inital field velocity for the fluid?
Hello I want to simulate the motion of a nano ball in the liquid. the liquid has a stale field velocity, angular velocity W(r) and has nothing with the angle theta due to symmetry. I would how to set...
View ArticleHow to solve a derived PDE equation with coefficient form?
Dear all: I had derived a PDE equation in attachment. But the result seems to be not correct. Please give me a help. Thanks a lot.
View ArticleHow to assign automated input values?
Can we assign input values to faces of an object via .csv file or through any web based tools?
View ArticleMeshing a surface with an interior point
I need to apply a point force on a point inside a shell surface. For this purpose I draw a point in geometry section. However, because of that point I can't mesh the surface with free quad or mapped....
View ArticleTaylor Hood or Crouzeix -Raviart element
Hello all I am using COMSOL for solving the velocity and concentration field. I am using quadratic elements. But I don't know what kind of quadratic elements COMSOL uses. Is it a Taylor Hood or...
View Articleapplying a periodic biphasic square waveform to a surface electrode
Dear friends, I want to apply an AC voltage/Current to a surface electrode placed on the human skin. I need a periodic waveform with unequal on and off time. How can I apply this stimulation pulse to a...
View ArticleEffect of sound pressure on refractive index/density
Hello fellow Comsol users, Most of my experience comes from structural mechanics and fracture and would like to ask a little help regarding pressure acoustics. The presence of high and low pressure in...
View ArticleThermal expansion model
I am trying to examine the stress distribution in a SiO2 film coated on a thick Si sample with a small Al bump on it, all heated to 700 K. I thought I built the model correctly, but the resulting...
View ArticleSimulation of Stirling Engine
Hello everybody I'm currently trying to simulate the fluid flow in a stirling engine (beta) which I've built from the following video:www.youtube.com/watch?v=X2qssmxA82U You should try building it;-)...
View ArticleMoving mesh 2D
Hello, I am trying to simulate the moving boundary for a 2D geometry. I started with a simple 2D geometry where 1 boundary is moving in the x-direction and 1 boundary in y-direction, but because the...
View ArticleUsing a Gaussian Pulse
Hi everyone, I'm actuallay working on a modeling of a laser pulse which is heating a front of a material in order to determinate the diffusivity, my current issue is that i would like to model my heat...
View Articletime interval for automatic remeshing
Hi, I would like to know the COMSOL keyword for the time interval when using the automatic remeshing module. I want to define a criterion based on the time that's why I need to know the actual number...
View ArticleWhy is the gradient of the voltage potential field not equal to the electric...
Hi, I have been working on a 3D model of a resistive current sensor, and I am trying to verify the high frequency (50-500Mhz) response. Essentially, i want to make sure that at a fixed current...
View ArticleMoving Mesh - Thermal stress coupling
Hello to all, I need to perform an RF frequency domain analysis on a waveguide which has been previously deformed by a Thermal Stress stationary analysis. In order to do this, I need to calculate the...
View ArticleIonization of air.
Hello. I have a model that comprises a container filled with air. From the outside there are two coils number of turns 1e6 supply current is 1e3 A in the container are two electrodes voltage + - + e7 V...
View ArticleBase vector coordinate system
I am modeling the anisotropic behavior of a plate that have fibers oriented in different directions. For this purpose, I am using the structural mechanics feature. I am orienting my fibers using a...
View Articleparameter sweep error when loading a geometry
I am applying a load to the top of the geometry shown while the bottom is fixed but i keep getting an empty parameter sweep error can u help me??
View ArticleFluid structure interaction and damping ratio
Hello, My model is a vascular cantilever beam (the first mode is pictured below). I work simultaneously on COMSOL and on my experiments. The channel is to be filled with a silicone fluid which will...
View ArticleMathematical particle tracing: Diffuse scattering wall condition
In Comsol 4.3a the diffuse scattering boundary condition is incorrect. it generates an angular distribution with respect to the surface normal of cos(theta), while the correct distribution is...
View ArticleCylinder section modelling
Hello all I wish to model structural mechanics in a section of a cylinder-like geometry consisting of longitudinal bars and radial rigid hoops supporting the bars. The full cylinder is too memory...
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