Hi, when I solve a PDE, it takes a lot of time. I closed the programme with task manager of windows. When I reopen the file, the programme is "reinitializing GUI" . I wait for almost an hour and nothing changed. At this time I cann't do anything else in the software. How can I solve this problem?
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"Reinitializing GUI" for a long time
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Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
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Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
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Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
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Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
↧
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Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
↧
Backward facing step
For a project we need to make a simulation with a backward facing step at different Reynoldsnumbers. The fluid flow is laminar and de distance after the step is only 40 cm. What kind of adjustments I need to make of the outlet?
Ward
Ward
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FSI (Fluid-Structure Interaction) and Transport of Diluted Species Multiphysics
Hello, I am working on a project that has been troubling me for quite some time. I am trying to combine FSI (Fluid-Structure Interaction) with Transport of Diluted Species for an actuator-based drug releasing device in 2D axial setting. The simulation that I am working on does not involve any electric field nor magnetic field (although in reality it does. Instead, I am using boundary load for force created by magnetic field).
The problem is that when I run FSI or Transport of Diluted Species separately, they give expected result with very good accuracy. It's when I combine two physics together, either in separate steps in a study (ie two time-dependent studies) or in one time-dependent studies, the result does not come out correctly. I have been set to run FSI first then transport of diluted species since I figured the convection process entirely depends on the velocity profile created from FSI, but not the other way around.
Also, the simulation seems to work alright as long as the boundary load is applied up to certain time. I am using a sine wave to test the oscillating nature of the boundary load. I shifted the sine wave to always be applied in negative z-direction throughout the simulation. But once an extrema of boundary load is reached and the load starts to change its change in direction (changing derivative of the boundary load if you consider the boundary load as some sinodual function), the simulation starts to act weird.
If specific dimension is required to solve this problem, I will put the general dimension in reply, but for the time being, is there something, like in solver settings or module to "smooth" the multiphysics simulation like deformed mesh physics, that I am missing before running the simulation? I am fairly new to using COMSOL, and any input and help on how to address this issue will be very much appreciated.
The problem is that when I run FSI or Transport of Diluted Species separately, they give expected result with very good accuracy. It's when I combine two physics together, either in separate steps in a study (ie two time-dependent studies) or in one time-dependent studies, the result does not come out correctly. I have been set to run FSI first then transport of diluted species since I figured the convection process entirely depends on the velocity profile created from FSI, but not the other way around.
Also, the simulation seems to work alright as long as the boundary load is applied up to certain time. I am using a sine wave to test the oscillating nature of the boundary load. I shifted the sine wave to always be applied in negative z-direction throughout the simulation. But once an extrema of boundary load is reached and the load starts to change its change in direction (changing derivative of the boundary load if you consider the boundary load as some sinodual function), the simulation starts to act weird.
If specific dimension is required to solve this problem, I will put the general dimension in reply, but for the time being, is there something, like in solver settings or module to "smooth" the multiphysics simulation like deformed mesh physics, that I am missing before running the simulation? I am fairly new to using COMSOL, and any input and help on how to address this issue will be very much appreciated.
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Velocity gradient expression in 2D-axisymmetric
Hello,
the velocity gradient tensor for a 2D-axisymmetric problem presents, for the phiphi component, the following expression
chns.graduDGphiphi = if(abs(r)<0.0010*h,d(u,r),u/r)
does anyone know the meaning? I can guess that is introduced to avoid spurious effects at the axisymmetric boundary but still it is not totally clear to me.
Best,
J
the velocity gradient tensor for a 2D-axisymmetric problem presents, for the phiphi component, the following expression
chns.graduDGphiphi = if(abs(r)<0.0010*h,d(u,r),u/r)
does anyone know the meaning? I can guess that is introduced to avoid spurious effects at the axisymmetric boundary but still it is not totally clear to me.
Best,
J
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What is the motivation of new Nonlinear Structural Materials Modele in Comsol 4.3 ?
In my opinion Comsol Multyphysics was a tool for all. However, I am disappointed by the new Nonlinear Structural Materials Module. Since in earlier versions, comsol had already nonlinear material moduls for hyperelasticity, plasticity, creep, etc. Now Comsol wants to charge extra cost for these models in new versions :( Is there any meaningful explanation for this? I would undersand the pipe flow and corrosion modules but not nonlinear structural materials.
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Grain Modeling
In ComSol 4.2 how can we give different crystal to different grains Please suggest any method , as I am able to change crystal orientation of whole model but not of each boundary unit separately.
Please guide me with it.
Please guide me with it.
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the electric potential dependent on temperature
hello,
please help me
i am trying to make a model of an electrode in a cylinder of biological tissue, i want to make the electric potential on the electrode dependent on the temperature of the tissue, where if the temperature of the tissue become 90 deg C for example the electric potential on the electrode become zero.
i don't know how can i make that.
basant
please help me
i am trying to make a model of an electrode in a cylinder of biological tissue, i want to make the electric potential on the electrode dependent on the temperature of the tissue, where if the temperature of the tissue become 90 deg C for example the electric potential on the electrode become zero.
i don't know how can i make that.
basant
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thermally resistive layer
Hi everyone,
I am modeling a pipe with fluid circulating within by coupling heat transfer and fluid flow and the pipe diameter is defined in the geometry section.
i need to define the pipe wall thickness for my pipe as well which i do it with adding a thermally resistive layer in heat transfer physics and define the conductivity as well as the wall thickness.
my question is that considering the pipe wall thickness, is the pipe diameter defined in building the geometry inner diameter or the outer one?
Regards
ASAL
I am modeling a pipe with fluid circulating within by coupling heat transfer and fluid flow and the pipe diameter is defined in the geometry section.
i need to define the pipe wall thickness for my pipe as well which i do it with adding a thermally resistive layer in heat transfer physics and define the conductivity as well as the wall thickness.
my question is that considering the pipe wall thickness, is the pipe diameter defined in building the geometry inner diameter or the outer one?
Regards
ASAL
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Simulation of leakage flux from transformer
Hello.
I've tried to simulate a quantity of leakage flux from transformer by using COMSOL 4.3a. To do this, I made a simple transformer model with LiveLink for AutoCAD.(I want to attach mph file, but its size is too big to attach)
And I chose "mef" module for simulation. But an error message comes out. Here is the message.
The following feature has encountered a problem:
Failed to find a solution.
Divergence of the linear iterations.
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)
- Error: Failed to find a solution.
I'm a beginner of COMSOL, so I can't find any solutions to fix this error. Is there any way to fix this error?
Regards,
Mizuki
I've tried to simulate a quantity of leakage flux from transformer by using COMSOL 4.3a. To do this, I made a simple transformer model with LiveLink for AutoCAD.(I want to attach mph file, but its size is too big to attach)
And I chose "mef" module for simulation. But an error message comes out. Here is the message.
The following feature has encountered a problem:
Failed to find a solution.
Divergence of the linear iterations.
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)
- Error: Failed to find a solution.
I'm a beginner of COMSOL, so I can't find any solutions to fix this error. Is there any way to fix this error?
Regards,
Mizuki
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Sessile droplet
I want to put a sessile droplet inside a channel. How to create a droplet of a specific material ? and how do I choose the model ?
As a reference I was wondering about the model in one the Paper - A Dynamic Electrowetting Simulation using the Level-Set Method-- www.comsol.co.in/papers/5283/
How do I replicate this paper in simulation?
Is the model available on Comsol website?
I was not sure that I can at all do anything like this in Comsol before I came across the paper.
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2D magnetic field streamline plot from cut plane
Hi, I have a question on the streamline plot.
I have build the 3D emf model on 6 parallel bar with the same current density. bar cross section was in YZ plane
The 3D streamline could be clearly seen. we could see the yz streamline in the 3D streamline plot.
But when I add a 3D cut plane in the data set. the 3D cut plane correponds to the YZ plane.
Then we plot the 2D streamline plot. The plot is totally different from the yz 3D streamline plot.
So could everyone pls tell me the reason?
I have build the 3D emf model on 6 parallel bar with the same current density. bar cross section was in YZ plane
The 3D streamline could be clearly seen. we could see the yz streamline in the 3D streamline plot.
But when I add a 3D cut plane in the data set. the 3D cut plane correponds to the YZ plane.
Then we plot the 2D streamline plot. The plot is totally different from the yz 3D streamline plot.
So could everyone pls tell me the reason?
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mesh
Hi ,
I am trying to see the accuracy of the numerical solution with different meshes and I am using analytical solution for comparison. As long as the mesh is refined the numerical model is more accurate.
I ran simulations for different meshes and I have the error between solutions.
What I don't understand is why after a certain mesh resolution, the error is not decreasing any more.
Can someone explain to me why ?
I am trying to see the accuracy of the numerical solution with different meshes and I am using analytical solution for comparison. As long as the mesh is refined the numerical model is more accurate.
I ran simulations for different meshes and I have the error between solutions.
What I don't understand is why after a certain mesh resolution, the error is not decreasing any more.
Can someone explain to me why ?
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how to define Heat source?
Hi,
I use COMSOL to simulate a microheater to heat the polymer waveguide on Silicon substrate.
The model is 2D. Silicon substrate serve as the heat sink at 25 degrees. When I set the microheater to 300 degrees, I can get a right a temperature distribution.
But now I want to set the microheater as the Heat source,and use the general source as 1000 W/m3. I set Bottom boundary at 25 degrees, and other boundaries as the Thermal Insulation. I can't get a right temperature distribution.
Can any experts on COMSOL tell me the reasons? Very urgent! Than you!
The version is Comsol 4.2.
I use COMSOL to simulate a microheater to heat the polymer waveguide on Silicon substrate.
The model is 2D. Silicon substrate serve as the heat sink at 25 degrees. When I set the microheater to 300 degrees, I can get a right a temperature distribution.
But now I want to set the microheater as the Heat source,and use the general source as 1000 W/m3. I set Bottom boundary at 25 degrees, and other boundaries as the Thermal Insulation. I can't get a right temperature distribution.
Can any experts on COMSOL tell me the reasons? Very urgent! Than you!
The version is Comsol 4.2.
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Parametric Sweep in order to change the location of a point
Hi,
I'm using the Parametric Sweep in order to change the location of a point who separate edge into two lengths; each has a different boundary condition. (One defined by me and the other one is the default condition -zero flux)
The location of the point (defined by the parameter "d2" in the y-axis and on the edge at the x-axis) defines the distance which is the size controlled by the B.C defined by me.
The problem is, whenever the parameter "d2" been modified, the B.C (who defined by me) go through all of the edge regardless to the point location.
Thank you in advance
I'm using the Parametric Sweep in order to change the location of a point who separate edge into two lengths; each has a different boundary condition. (One defined by me and the other one is the default condition -zero flux)
The location of the point (defined by the parameter "d2" in the y-axis and on the edge at the x-axis) defines the distance which is the size controlled by the B.C defined by me.
The problem is, whenever the parameter "d2" been modified, the B.C (who defined by me) go through all of the edge regardless to the point location.
Thank you in advance
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geometry problems
Hi all,
My question is, if you build up a block first, then you build up a sphere inside the block.
Is it means that the volume which was belonged to the block is taken by the sphere?
If so, is it means that the surface of sphere is doubled? Since, I would expect that one is for the outer surface of sphere, one is for the inner surface of the block.
Thanks
Ferris
My question is, if you build up a block first, then you build up a sphere inside the block.
Is it means that the volume which was belonged to the block is taken by the sphere?
If so, is it means that the surface of sphere is doubled? Since, I would expect that one is for the outer surface of sphere, one is for the inner surface of the block.
Thanks
Ferris
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