I want to merge 2 mesh. A cylinder with a slab. How can I do that?
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Merge two mesh
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Hi: need help on electro-rotation studies
Hi I work on electro-rotation studies through dielectrophoresis(DEP).
Problem involves lot of variables, however I would like to know a way to obtain rotational simulation due to DEP?
Currently we got electromechanics which comes close enough but its hard to solve any electro-rotation problems.
Attached is the file consisting of model along with boundary conditions, basically DEP torque is dependent upon frequency of the applied field, complex permittivity and conductivity of the material and the surrounding medium.
I cant solve time dependent study because time goes to constant/ singularity due to the overlapping of phase varying AC sine waves. If I want to use frequency domain study then I dont know how to define the time-frequency varying voltage!! I cant use waveform in frequency study because now, voltage is a function of frequency instead of time like sine(2*pi*freq*t+phase).
Please guide me on this.
Thanks with Regards
Prateek Benhal
PhD candidate, Department of Mechanical Engineering
Division of applied biotechnology and micro-robotics
University of Canterbury, NZ
prateek.benhal@pg.canterbury.ac.nz
Phone: +64-3-364-2987 7228(ext.)
Problem involves lot of variables, however I would like to know a way to obtain rotational simulation due to DEP?
Currently we got electromechanics which comes close enough but its hard to solve any electro-rotation problems.
Attached is the file consisting of model along with boundary conditions, basically DEP torque is dependent upon frequency of the applied field, complex permittivity and conductivity of the material and the surrounding medium.
I cant solve time dependent study because time goes to constant/ singularity due to the overlapping of phase varying AC sine waves. If I want to use frequency domain study then I dont know how to define the time-frequency varying voltage!! I cant use waveform in frequency study because now, voltage is a function of frequency instead of time like sine(2*pi*freq*t+phase).
Please guide me on this.
Thanks with Regards
Prateek Benhal
PhD candidate, Department of Mechanical Engineering
Division of applied biotechnology and micro-robotics
University of Canterbury, NZ
prateek.benhal@pg.canterbury.ac.nz
Phone: +64-3-364-2987 7228(ext.)
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Moving 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 boundaries are connected in one point, that point cannot move in x and y in the same time. For this reason i did a filet and the added boundary is moving in x and y.
My problem is that after specifying the velocities for which the boundaries are moving and hit compute, inverted mesh elements appears after 11 seconds. Even if I change the mesh quality the problem is not solved.
Mai I know why is behaving like this and what should I do in order to move the boundary further?
I attached the model for a better view.
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 boundaries are connected in one point, that point cannot move in x and y in the same time. For this reason i did a filet and the added boundary is moving in x and y.
My problem is that after specifying the velocities for which the boundaries are moving and hit compute, inverted mesh elements appears after 11 seconds. Even if I change the mesh quality the problem is not solved.
Mai I know why is behaving like this and what should I do in order to move the boundary further?
I attached the model for a better view.
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nimor loss coefficient
can i add minor loss coefficient (K) to to a boundary
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Simualtion of Electrospraying using comsol
Hello
How to find surface charge density during electrospraying?How to couple laminar two phase flow with electrostatics?
Thanks
Alok
How to find surface charge density during electrospraying?How to couple laminar two phase flow with electrostatics?
Thanks
Alok
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Deformation in a Tire
Hi everyone,
I am currently trying to model a tire going over a ledge and examining the stresses and deformation caused by the impact of the ledge with the tire. I am applying applying 5000 N of force that is dependent on the location of the ledge. In other words, the force in the x direction is 5000*cos(theta) in the x direction and 5000*sin(theta) in the z direction, where theta varies between 220 and 270 degrees. There is also an internal pressure being applied of 70 psi.
I am having trouble actually getting the deformation to occur. The force is applied in the area where the ledge meets the tire, but no deformation actually occurs.
If you need more information I will gladly provide it. Any insight is greatly appreciated.
Thanks
The attached picture is one of the results I am getting. A force is applied in that small cut-out region that represent where the ledge meets the tire. As shown, stresses are caused by the force, but no deformation occurs. The inside part of the tire has a fixed constraint on it, which is where the metal would be on a real tire.
I am currently trying to model a tire going over a ledge and examining the stresses and deformation caused by the impact of the ledge with the tire. I am applying applying 5000 N of force that is dependent on the location of the ledge. In other words, the force in the x direction is 5000*cos(theta) in the x direction and 5000*sin(theta) in the z direction, where theta varies between 220 and 270 degrees. There is also an internal pressure being applied of 70 psi.
I am having trouble actually getting the deformation to occur. The force is applied in the area where the ledge meets the tire, but no deformation actually occurs.
If you need more information I will gladly provide it. Any insight is greatly appreciated.
Thanks
The attached picture is one of the results I am getting. A force is applied in that small cut-out region that represent where the ledge meets the tire. As shown, stresses are caused by the force, but no deformation occurs. The inside part of the tire has a fixed constraint on it, which is where the metal would be on a real tire.
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1D plot
Hi
I simulate the waveguide with mode analyses(2D) in x and y direction, now i want to plot 1D plot in z direction according to x and y how can i do that?
I simulate the waveguide with mode analyses(2D) in x and y direction, now i want to plot 1D plot in z direction according to x and y how can i do that?
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Getting capacitance from Impedance/admittance
Good day!
I am modeling an impedance/capacitance sensor. I have a static model and the results are very promising, now Im trying to expand my model and model a frequency domain study: the voltage applied is a frequency parameter sweep between 1 and 8 MHz. Using the Electric currents interface I can get admittance of the system as a variable but I would also like to know the capacitance of the system.
Since the device is basicaly a microstrip capacitor then I can get the Capacitnace by dividing theimaginary part of admittance by angular frequency.
C = jY/w.
But is there a way to do it automaticaly? There is an example in the library - capacitance in a microstrip(Model ID 966), its exactly what Im trying to do but it is made for 3.5 and when i open it in 4 or 4.1 it seems to work as it should: there are electro statics and magnetic fields physics interfaces and the study is stationary... Solving it brings up an error. Reading the .pdf file for it I found that you can do that by plotting "imag(Y11_emqap)/omega_emqap". However the the variable with imaginary part of admittance doesnt seem to be present in the electric currents interface...
Any help apreciated.
Cheers.
- Fjodor
I am modeling an impedance/capacitance sensor. I have a static model and the results are very promising, now Im trying to expand my model and model a frequency domain study: the voltage applied is a frequency parameter sweep between 1 and 8 MHz. Using the Electric currents interface I can get admittance of the system as a variable but I would also like to know the capacitance of the system.
Since the device is basicaly a microstrip capacitor then I can get the Capacitnace by dividing theimaginary part of admittance by angular frequency.
C = jY/w.
But is there a way to do it automaticaly? There is an example in the library - capacitance in a microstrip(Model ID 966), its exactly what Im trying to do but it is made for 3.5 and when i open it in 4 or 4.1 it seems to work as it should: there are electro statics and magnetic fields physics interfaces and the study is stationary... Solving it brings up an error. Reading the .pdf file for it I found that you can do that by plotting "imag(Y11_emqap)/omega_emqap". However the the variable with imaginary part of admittance doesnt seem to be present in the electric currents interface...
Any help apreciated.
Cheers.
- Fjodor
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Step function
Very simple question, but I can't find out how to do it.
I have a external temperature, "Temperature 1", which is 100 C. After 330 seconds I would like it to drop 80 degrees to 20 degrees. I should be able to use a step funtion, but can't figure out how to. An easier approach is also very welcome. Thanks in advance!
I have a external temperature, "Temperature 1", which is 100 C. After 330 seconds I would like it to drop 80 degrees to 20 degrees. I should be able to use a step funtion, but can't figure out how to. An easier approach is also very welcome. Thanks in advance!
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Thermal 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 stress distribution diagram is quite different from what I expected. Specifically, the stress gradient is not existent at the boundary of Al and other metals. Can anyone tell me what may be the problem with my model? Especially concerning the boundary conditions? Thanks.
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How to solve and verify a ODE equation?
How to solve a ODE equation with mathematical problem?
And how can I verify the result correct with the mathematical answer?
Thanks for help.
And how can I verify the result correct with the mathematical answer?
Thanks for help.
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State Space Export
Hi ,
i have build a simple cantilever beam model using time depented model.
after defining the points of forces and parameters, i want to export the model to matlb (State Space Matrices) so i could "play" with the paramters and their location.
for example applying force at the tip = 100sin(theta(t)) and applying more forces to restrain the system.
i have searched the forum and found the mphstate function but i wasn't able to use it.
would like to get some help and tipps :)
(sorry for my poor english)
Regards, Eyal
i have build a simple cantilever beam model using time depented model.
after defining the points of forces and parameters, i want to export the model to matlb (State Space Matrices) so i could "play" with the paramters and their location.
for example applying force at the tip = 100sin(theta(t)) and applying more forces to restrain the system.
i have searched the forum and found the mphstate function but i wasn't able to use it.
would like to get some help and tipps :)
(sorry for my poor english)
Regards, Eyal
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photonic crystal fiber
Hi , I am an electronic engineer doing master degree research about raman amplificaion by using photonic crystal fiber, I want to calculate the confinement lose by using PML around my fiber strucrutre, but l still can't get the complex value of neff , so would you please help me by informing me how to implement the PML . please contact me at my email : baselhaji@gmail.com
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Microweave frequency function with temperature
Hi I am studying an microwave problem in frequency domain, where the frequency of the waveguide problem needs to change during the simulation.
I successufly, made one simulation by definying a frequency in function of the physical time "t".
I need to make the same frequency function but depending of the sample temperature, can be from one temperature probe or the average temperature in the sample.
Has anyone experience in this?
Thanks in advance.
I successufly, made one simulation by definying a frequency in function of the physical time "t".
I need to make the same frequency function but depending of the sample temperature, can be from one temperature probe or the average temperature in the sample.
Has anyone experience in this?
Thanks in advance.
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import mesh with the edited *.mphtxt file
Hi, everyone:
I have a geometry mesh, and I knew the mesh node's coordinates: x, y, z in matlab workspace.
I want to import the mesh into COMSOL , and set the point whose coordinates were knew as the mesh nodes .
How to do this? Do I need to write a *.mphtxt file of the mesh? And how to edit the *.mphtxt files?
THanks for your help.
YH
I have a geometry mesh, and I knew the mesh node's coordinates: x, y, z in matlab workspace.
I want to import the mesh into COMSOL , and set the point whose coordinates were knew as the mesh nodes .
How to do this? Do I need to write a *.mphtxt file of the mesh? And how to edit the *.mphtxt files?
THanks for your help.
YH
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Multiphysics how to make communication between different physics (same model?)
Hi I need to make a coupling between three physics:
- MicrowaveHeating - Frequency Domain - Transient
- Non-Isothermal Laminar Flow
- Radiation Model
My problem is that I required to use the same time step in three physics but the different models have temperature, is this temperature shared by the physics automatic? Does any one know a tutorial, that shows how the communication is done between physics?
Thanks in advance.
- MicrowaveHeating - Frequency Domain - Transient
- Non-Isothermal Laminar Flow
- Radiation Model
My problem is that I required to use the same time step in three physics but the different models have temperature, is this temperature shared by the physics automatic? Does any one know a tutorial, that shows how the communication is done between physics?
Thanks in advance.
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Multiphysics Swirl Flow with Convection&Conduction problem
Hey all,
so I am a beginner in Comsol. I designed a mixer in 2D axial symmetry and solved the problem with a given angular velocity w and found the stationary velocity field.
Now let's say the mixers submerges in 5 degrees Celsium water so the side walls have a constant 5 degrees Celsium temperature. I want to find the temperature field from t=0 (submersion) to t=x aka transient analysis.
Problem is, when I add the Convection and Conduction model, add subdomain and boundary conditions and solve with the transient solver while bounding the velocity field option with the variables of my previous solved problem, i get amazingly high temperatures and no change in the temperature field throughout time (we're talking about 10^46 T ??!!).
I have no clue what's going wrong, I suspect something with the solver manager and the solver parameter, tabs which aren't very clear to me.
In any case I've attached the 3.5 Comsol file. Any kind of help is appreciated.
so I am a beginner in Comsol. I designed a mixer in 2D axial symmetry and solved the problem with a given angular velocity w and found the stationary velocity field.
Now let's say the mixers submerges in 5 degrees Celsium water so the side walls have a constant 5 degrees Celsium temperature. I want to find the temperature field from t=0 (submersion) to t=x aka transient analysis.
Problem is, when I add the Convection and Conduction model, add subdomain and boundary conditions and solve with the transient solver while bounding the velocity field option with the variables of my previous solved problem, i get amazingly high temperatures and no change in the temperature field throughout time (we're talking about 10^46 T ??!!).
I have no clue what's going wrong, I suspect something with the solver manager and the solver parameter, tabs which aren't very clear to me.
In any case I've attached the 3.5 Comsol file. Any kind of help is appreciated.
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Microwave heating model with multiple frequencies
Hi,
With the Microwave heating model, with a frequency-transient study is possible to simulate multiple frequencies in a well defined bandwidth? I have a input wave with a fixed bandwidth defined by a square function or a gaussian pdf.
I could do this with a time domain study, with the transient electromagnetic wave model. Bit if it is possible with the microwave heating model, this will be more apreciated.
Thanks in advance.
With the Microwave heating model, with a frequency-transient study is possible to simulate multiple frequencies in a well defined bandwidth? I have a input wave with a fixed bandwidth defined by a square function or a gaussian pdf.
I could do this with a time domain study, with the transient electromagnetic wave model. Bit if it is possible with the microwave heating model, this will be more apreciated.
Thanks in advance.
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How to plot the relative error?
I've just spent more than a whole day troubleshooting my model.
However, if I could plot the relative error over the geometry, I believe it would have been solved in minutes.
There was a problem localised to a particular junction between domains.
So, is there any way to visualise the relative error in a domain? Maybe via Livelink for Matlab? I couldn't find anything about that.
However, if I could plot the relative error over the geometry, I believe it would have been solved in minutes.
There was a problem localised to a particular junction between domains.
So, is there any way to visualise the relative error in a domain? Maybe via Livelink for Matlab? I couldn't find anything about that.
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cone in liquid
hello
I have two questions first, I want to swing the cone (oscillate) in a liquid medium so what you have to choose another model as solid Mechanics????
Secondly I will stay strictly close and the cone of the liquid surface to see the formation of the meniscus
I'm starting with COMSOL ?
thank you for your answer?
I have two questions first, I want to swing the cone (oscillate) in a liquid medium so what you have to choose another model as solid Mechanics????
Secondly I will stay strictly close and the cone of the liquid surface to see the formation of the meniscus
I'm starting with COMSOL ?
thank you for your answer?
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