Problem with transport of diluted species mass conservation
Dear Comsol Community, My model is a 2d axisymmetric geometry, composed by one fluid layer and many porous layers. I'm modeling both laminar flow and transport of diluted species. This chemical species...
View Articleabout the steady and unsteady simulations
Dear Sir or Madam, I meet some problems about the simulations of fluid flow in channels. When you do some simulations related to fluid flow, how do you judge whether it is a steady issue or not? For...
View ArticleError in pressure drop simulation
Hi! I get the following error when trying to simulate the pressure drop in a long pipe with a lot of inlets (se attached model). Failed to find a solution. Segregated group 1 Matrix has zero on...
View ArticleUpdating Variables During a Simulation
Hi I'm trying to run a Laminar Flow simulation where I have coupled my outlet boundary conditions to a set of boundary ODEs. I am however getting an error "Failed to evaluate variable Jacobian". I...
View ArticlePhase change of a metal with version 4.4 and version 5.0 does not match why ?
Hi I am trying to make a simulation of a melting process of a square of Silicon 0.5m x 0.5m fixed temperature of 1941K to the left wall and 1687 K (melting point of silicon) to the right wall ( this...
View ArticlePixel size and effective permeability
I am trying to calculate the effective permeability for a 3D porous media with the size of 3000x3000x3000 pixels and 10x10x10 micro^3. I resized (not crop) my model since my 3D model is very large to...
View ArticleModeling of fluid flow caused by deformable objects.
I have a stationary object in a stationary fluid at t=0s. At that time, the object (a fixed rectangle) starts moving in a sine wave (eg how flagella or cilia move). Due to this the fluid around it gets...
View ArticleMelting&Free surface Marangoni flow
Greeting, I am also dealing with the same case about laser melting. The problem I am trying solving is that the temperature field do not change with the volume fraction of the metal liquid during melt...
View Articlecylinder flow
There are Two cases.In the first case the solution converges and gives an accurate result. However in the second case, the solutions diverge. case 1: The circle and rectangle are attached. Only the...
View ArticleDeformation of a water droplet in a cilindric pipe with a toluene flow
Hello, I'm new in Comsol and I'm trying to solve a problem for an exam. I have a droplet of water placed on the axis of a cilindric pipe, and in the pipe flows toluene. I have to evaluate the...
View ArticlePDE dependent variable returns as an undefined variable
My problem is below: I'm using Coefficient PDE mode. There are two PDEs and the dependent variables are A and B, seperately. Now I defined a variable C in global variable and C=A^2+B^2. When I compute...
View ArticlePlasma chemistry assumption
Hello everybody I am modelling a plasma actuator used for aerospace application (boundary layer separation control, airfoil leading edge flow separation control). I am having a trouble in finding any...
View ArticleDeformation of liquid droplet
I am new to COMSOL, so I am referencing a work on deformation of liquid droplet impacting a solid surface. I tried to recreate the same model as that work. But I ran into several problems. As I tracked...
View Articlefluid flow aroud a cylinder
Does anyone know why in the "cylinder flow" example of the comsol tutorial, the solution is not accurate? The drag coefficient I have calculated is 2.5, however in the papers it is 1.34 (Reynolds=100...
View Articlewhy the plastic zone is so different between COMSOL and FLAC.
Hi Mr. Ivar. I do a test use FLAC3D and COMSOL, the same model condition and mesh are used in them, and the result show that their Stress distribution and Displacement distribution are similarly, but...
View ArticleHow to enforce minimum gap between two vibrating structures- FSI
Hey, I am working on vocal fold aerodynamics. I am trying to perform 2D Fluid Structure Interaction simulations in which the air flows between the two vocal folds. The gap between them is very...
View ArticleHow to enforce minimum gap between two vibrating structures- FSI
Hey John, I am working on vocal fold aerodynamics. I am trying to perform 2D Fluid Structure Interaction simulations in which the air flows between the two vocal folds. The gap between them is very...
View ArticleComsol 4.0 Level Set Method
I have just started to play around with COMSOL version 4.0. It seems that the level set method has not been implemented. Am I correct or have I just failed to find it? The level set method or an...
View ArticleBoundary Conditions: Pressure head vs. Pervious Layer
We are creating a 2D, steady state, Darcy model of a clayey embankment acting as a dam with a sand foundation. Upstream of the dam is at a higher water level then downstream, both are constant. A...
View ArticleDrift Diffusion and Heavy species transport coupling
Hello I am modelling an AC-DBD plasma actuator (model is attached). I have modeled my time-dependent ac circuit and have proceeded to include the drift diffusion model and heavy species transport...
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