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On nonlinear diffusion

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Hello, I am working on a system of a reaction diffusion ( whose solution is u1) and two ordinary differential equations (whose solutions are u2 and u3). The problem is that the diffusion term in the PDE depend on u2. Is it possible to solve such problem with Comsol because I checked the library and i couldn't find a way to resolve that.

Thank you


An unexpected error occurred while opening comsol

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Help! Help! Help! Yesterday, I used Comsol normally, but today I can not open it anymore. The detail error is given as follows. The solution to rename/remove the vXX folder located at C:\Users\%USERNAME%.comsol\vXX is also useless! Someone can help me?

2018-09-13T10:46:20.116+08:00 FlLocale - SystemProperties do not contain any locale setting. 2018-09-13T10:46:20.438+08:00 Constructing a FlLocale:zh_CN

2018-09-13T10:46:20.868+08:00 Could not load file or assembly 'cstextrenderer_wpf.dll' or one of its dependencies. Not a valid Win32 application. (Exception from HRESULT: 0x800700C1)

2018-09-13T10:46:20.872+08:00 at ComsolDesktop.TextRenderer.CsTextRenderer.Init(String distrDir) at ComsolDesktop.DesktopApplication..ctor() at ComsolDesktop.App.OnStartup(StartupEventArgs e) at System.Windows.Application.<.ctor>b__1(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

seismic acceleration time history input

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I am modeling structure fixed on the ground,the acceleration time history need to be apllied to the boundary .So I have to set prescribed displacement/rotation and prescribed acceleration to the boundary to the same region simultaneously.But they cannot work together, the former is overriden by the latter. I want to know if the comsol can realize my idea,how. If it could not do this in this in my idea, some other mehod is also OK.

the unit of the emitted power

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I am modelling an LED using comsol and I want to get the LED emitted optical power . Then I used the "semi.ot1.dP_dE" which name is the emitted power per unit volume and energy and the unit of the "semi.ot1.dP_dE" is "1/(m^3*s)" . But the unit of the power is "W".
The result "2.8E16" I have got is far from the accurate optical power value . i think the "semi.ot1.dP_dE" is not the optical power. So, which one is the optical power?
anyone can help me? thanks a lot!

Husband Wife Dispute Problem Solution molvi ji +91-9829644411 united kingdom

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Husband Wife Dispute Problem Solution molvi ji +91-9829644411 united kingdomHusband Wife Dispute Problem Solution molvi ji +91-9829644411 united kingdom

HOW I GOT MY EX BOYFRIEND/GIRLFRIEND BACK FAST whatsapp +1(978) 406 9575

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Can one program Comsol to iterate through the physics of a model?

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I have an electrode stack and need to solve for the potential at each one of the 37 electrodes when only one is powered while the rest aren't. That is, Enable electrode 1 at 1V, the rest of the electrodes disabled, solve, export data as .txt Enable electrode 2 at 1V, disable previous electrode, solve, export data as .txt . . . I would have to do this 37 times, when each computation takes ~14 mins. Is there a way to let COMSOL running with this iteration or is this the essence of COMSOL's manual labor?

-Dalila

Limiting a Variable over a Domain

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I was wondering if it is possible to impose a constraint on a variable over a given domain (an upper bound specificallly). For example, if I would like to limit the concentration of a species to less than a given number because it would be physically impossible for it to go above a certain amount, how would I do so?


Boundary conditions or PEC/PMC on the boundaries of the cubic unit cell

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How one can apply the boundary conditions or PEC/PMC on the boundaries of the cubic unit cell if the angle of polarization of the incident electromagnetic wave is rotating? For example, the angle changes from 0 to 90 degrees with an interval of 10 degrees.

Thermodynamic simulation of isochoric process

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Dear all, I would like to know the possibility to simulate a thermodynamic isochoric process in a closed volume of gas (for example N2). Is this possible in COMSOL?

Nice regards

Results of Parameter Estimation

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I'm trying to do inverse heat transfer problem with Parameter Estimation module. All works fine, however I can't understand where I can find result of optimization. How can I see the value of parameter that I want to find?

Making a license server available to engineers "in the field" i.e. over the internet

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Hi all,

I'm an IT professional rather than an engineer but have been approached by a COMSOL client wishing to make his floating license available to his engineers whilst they are working at client sites or other remote locations.

He has a floating license and is looking to me to sort out and host the license server, including making it work over the internet.

At the moment I'm thinking either: 1) a full VPN for his remote engineers to have effective on-network presence and therefore access to the license server. 2) opening a firewall port and configuring port-forwarding to the license server so the remote engineers would get their licenses from something like companydomain.com:9999 where 9999 (for example) is the port number we would forward through to the COMSOL license service.

Option 1) would be the most secure, but we feel that then the end-users traffic (all of it - web browsing, email etc) would be forced over the VPN and through our network, which we don't want. Option 2) leaves a firewall port open to the public internet, and could be abused.

I think we might want to recommend to the client that we configure a solution but it be installed and hosted at his location rather than ours......

Has anyone got a suggestion on this?

Many thanks, Glen.

How to update parameter value at each step in COMSOL solver?

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Dear community,

I have a numerical problem I am trying to solve where I have to replace a variable inside my PDEs with an integral value calculated at each time step of the numerical procedure.

So, call my variable parameter x and call the field i am solving for Y.

I need to make sure that at each time step of the relaxation procedure x is replaced by Q/Integral (Y^2) over the domain, where Q is a constant I set. Convergence will then have a solution with an x that respects Q = x * int(Y^2).

Is there a way I can do this in COMSOL?

I apprecieate your help!

Gianni

Mesh problem

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Hello, NEW TO COMSOL. I had a 2D geometry and I changed it to 3D geometry. Now, I have found some problems with meshing and I couldn't use physics-controlled mesh. The errors are as follow: Failed to generate mesh for domain. - Domain: 2 Failed to respect edge element on geometry edge. - Edge: 210 Failed to move mesh point in domain. - x-coordinate: 0.00157114 - y-coordinate: -1.8e-005 - z-coordinate: 5e-006 Could you please help me?

Unknown Function or Operator

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Hi guys,

When I run study-get initial value, COMSOL comes out: Unknown function or operator. - Name: comp1.semi.gdm1.genext1

What I have did is definingthree parameters named Ve, Vd, Vc in Global Definitions-Parameters. And no other parameters have defined. Several similar questions have posted before but they don't solve my problem. I look forward to your suggestions. Thank you!

Best, Yicun


Related to use of physics

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We are putting a micro cantilever (Silicon material) of a fixed dimension inside a box and within the box we need to fill with SF6 gas. We are doing it by changing the permittivity of material 2 in model where as material 1 is material of micro cantilever & we got some result by changing the permittivity of material 2 but same thing we want to observe by changing the density of the gas. Here we are using Electro mechanics physics in comsol but using that physics we are unable to change the density of material 2 , if we are adding physical property like Density etc still the model is not using those values & taking only permittivity of gas. So what physics more we should use so that we can get Eigen Frequency by changing the density or pressure of material 2 means SF6. ( The model is only taking relative permittivity of material 2 and giving the result.). We are using COMSOL 5.3 version.

Singular matrix

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Hello everybody I had a 2D model and I changed it into 3D. My 2D model works well, but this 3D has an error: singular matrix. Can you help me?

Meshing very thin layers in nm

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Hi All,

I am trying to simulate a structure having 1cmx500 um of silicon over which 100 nm of dielectric (SiO2) is placed. I am unable to mesh such a thin layer of dielectric.

Can anyone give some inputs how to do?

Modeling of sample contamination and heat transfer in cryogenics vacuum chamber

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Hi, guys, I am modeling a sample of 100K transferred in ambient air, I want to know the water crystalized on the sample also the heat transfer process of my sample. How should I model the ambient air with water vapor and possibly know how quick the ice crystalize on my sample surface?

Problems with importing Solidworks Parts to COMSOL

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Hello All, I am trying to import a 3-D sketch part into COMSOL v. 5.2a but COMSOL says that the file is not compatible. My only option is to import as a mesh file. So, if anyone else has had this problem, could you please help me with either the correct format to import geometry (I have tried just about every Solidworks extension) OR how to "solidify" an imported mesh file into COMSOL. Please and Thank you.

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