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gradient of a vector
Dear all, could you write, how to define gradient of a vector in comsol in the user defined equations. For example, for a electric field(E) vector, can I write grad(E)? I wrote but comsol does not...
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Frequency Domain to Time Domain , COMSOL 5.2
Hi, I have a design which involves two antenna and a gap in between. I have estimated the e-field intensity through the gap, where e-field is a function of frequency and space. However, I need to...
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modeling smart sensor
Hey guys, I am working on a simulation regarding piezoelectric material. What I have is a half cylinder electrode with nanotubes growing radially on its surface. the electrode is then embedded in a...
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Several BH curves for one part
Dear all, currently I'm working on a simulation approach for polymer-bonded permanent magnets. Therefore I need to implement several BH curves for one part. Based on the temperatur of every finite...
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3d Laminar Flow
Good Afternoon I´m trying to run a very simple 3d simulation about an air flow that flows through a cylinder (radius=1,75mm) inscribed in a cube(side=4.3mm). Now, when I put between the inlet and...
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Complex Eigenfrequency value
Hi everyone, I am simulating a kind of resonator and now we want to generate the Eigenfrequency of this device. However, the Eigenfrequency that I get in the simulation is complex numbers! And I have...
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Time to reach steady state
Hi, I'm trying to calculate the time to reach steady state in a heat transfer transient analysis. Please let me know if anybody has an idea? Thanks, Krish
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Surface Plot in different coordinates
Hi all, I am evaluating a deformation (w value in comsol) of a cylndric surface. I got a 2D plot of the surface with the perpendicual displacement. Now I would like to export the data. I am able to do...
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Flow vector from a 3D solution into 2D
Hello, I have the following problem: I have a 3D simulation of a gas flow in Comsol 5.0. Now I want to add some heating effects, but as the geometry is cylindrical, a 2D axial symmetric model will do...
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Heat transfer
I want to define boundary load as a variable temperature as recorded from device. I used the Interpolation function to Import the data into comsol. Now, when I am trying to assign this as the boundary...
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What are "outer boundaries" and "internal boundaries"?
Hello. When I read the Corrosion Module User's Guide, I could not figure out the meaning of "outer boundary" and "internal boundary" exactly. So I want to know the exact meanings of them. In the...
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If statement in Deformed Geometry
Does anyone happen to know if an "if statement" (conditional statement) can be used in the deformed Geometry for prescribed mesh displacement? Meaning, using the CFD module, the deformed geometry only...
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Bike cab simulation - Relative error greater than relative tolerance
Hi, I´m trying to model a bike cab for my graduation project from university. I stated with a simple model based on the truss bridge tutorial so I can easily modify the tube sections and get fast...
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Import of temperature data into COMSOL
Dear all, I need to import the temperature for every element from another simulation into COMSOL 5.2. The other software (SigmaSoft) allows to export the calculated temperature information as .txt (see...
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Plot Electric field with respect to time along a certain line in RF, COMSOL 5.2
I have posted it yesterday. For some reasons I was not able to attach my file. I am posting it again here. I am kind of new in Comsol, so I am facing difficulties in solving this problem. It might be a...
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internal variable porosity permeability
I, beginner to COMSOL, am using poroelastic model in COMSOL fully saturated porous medium, all the pores are filled with fluid. Hence porosity is equal to the ratio of volume of the fluid to the total...
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Sweep a Postprocessing Parameter
Hello, I am running a stationary magnetic simulation. I have a 3D surface (a disc) over which I am integrating the normal magnetic flux density to get the total magnetic flux through the surface. With...
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Simple integration with limits
Hi All, I have a linear projection(located along the y-axis) giving the heat loss/unit length for a simple rectangular channel located on the same axis. I simply want to integrate along this linear...
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How to define a equation between the derivative of two variables
Hello, I am a new user of COMSOL 5.1, and I'm using the mathematics module to define my physical model. I defined two dependent virables: c (concentration) and phi (potential); I also defined two PDEs...
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secondary particle is different from primary particle
Hi, All, I am doing 2D charged particle tracing using COMSOL. I have electron bombarding some surface, and generate some positive ion at the surface which would accelerate and travel in the same...
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