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Ravi Kumar


University of Illinois

103 total contributions since 2016

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  • Knowledgeable Level 3
  • 6 Month Streak
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Answered
How can I resolve the error "PDE coefficients cannot be function of solution or time." in a static solution of a PDE.
What are the output arguments in you function call InterpolateDisplacement? [UVdispB, UVdispT, UVdispL, UVdispR]=InterpolateDis...

3 days ago | 0

Answered
How to create a copy of a pde model ?
Get hold of the handle that is provided as output, like: bc = applyBoundaryCondition(....) Now you can...

6 days ago | 0

Answered
How to apply the boundary conditons to the mass and stiffness matrices?
Use the 'nullspace' as second argument, you will get matrices with BC imposed by eleminating dirichlet DoFs. Regards, Ravi

6 days ago | 0

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Answered
Cannot apply multiple, region-dependent thermal properties in PDE Toolbox
This is a bug where solver fails to distinguish the functions as seperate based on some queries. Workaround is to define variati...

10 days ago | 1

Answered
How squareg works ?
Hi Pavel, I don't fully understand your question, but I can answer a portion on how to create square of different size. You can...

18 days ago | 0

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Answered
PDE tool box, internal heat generation and BC conditions
If the problem is axisymmetric, then you need follow the approach similar to this example: https://www.mathworks.com/help/pde/...

1 month ago | 0

Answered
How can i define PDE coefficient which is scalar matrix inside the boundary
Hi Kim, Is your ffunc depends on solution, i.e., using state.u? Can you provide sample data, also xv and yv? Regards, Ravi ...

1 month ago | 0

Answered
Boundary condition for multidomain geometry
Hi Urban, Would you be able to share your code and data? Geometric faces are identified by analyzing how drastic the normal ch...

1 month ago | 0

Answered
Retrieving indices of times for a time-dependent system of PDEs within applyBoundaryCondition()
You need to create an interpolant object, see for example, griddedInterpolant. Construct interpolant (may be one for each N), an...

1 month ago | 0

Answered
PDE Toolbox does not recognize subdomains in imported .stl geometry
STL with multiple bodies are imported as separate cells in PDE Toolbox. Essentially, the two cells are disconnected for analysis...

1 month ago | 0

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Answered
I find that the matlab official example "deflection-of-a-piezoelectric-actuator" cannot be correct
Hello Prof. Ciavarella, Can you provide a bit more details, reproduction code and expected results, of the modified setup to i...

1 month ago | 0

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Answered
What is the best way to fit parameters in the pdesolver to a set of datapoints?
You might need to use Optimization Toolbox in conjunction with PDE Toolbox to setup the objective function and constraints. Woul...

1 month ago | 0

Answered
plese help me solve this
You can use PDE Toolbox to solve this kind of heat transfer problem. Refer to the documentation on Heat Transfer problem setup i...

1 month ago | 0

Answered
How to change from dirichlet to newman conditions in a thermal model using PDE?
Hi Rubem, ThermalModel crated using thermalmodelS=createpde('thermal') lets you set up the problem in deomain specific funct...

2 months ago | 1

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Answered
evaluateGradient missing from pde toolbox
Hi Heidi, You need to have a results object in the workspace to access evaliuateGradient on the MATLAB path. Run any PDEModel ...

2 months ago | 0

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Answered
pde themral model, thermally connect two cells
Hi Derek, Multidomains in the imported geometry, using STL file, are not recoganized as connected cells of the same geometry. ...

3 months ago | 0

Answered
Simple compression of cylinder- results of finite element model don't make sense
Hi Clay, Your BCs are correct. I think the load you are applying is resulting in very small defomration. This is causing the d...

3 months ago | 0

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Answered
error in heat transfer example
Hi Charlie, What version of MATLAB are you running R2018a or R2018b. In any case, you should not see this error if you run t...

3 months ago | 0

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Answered
PDE Toolbox: Using different temperature-dependent thermal conductivities
I did not realize this in my initial response, both of your k values goes to inf when u=0. Try the following following instead, ...

3 months ago | 0

Answered
PDE Toolbox: Using different temperature-dependent thermal conductivities
Both k1 and k2 yields zero when state.u = 0, this is causing solver to misinterpret them as same functions. You can get around t...

3 months ago | 0

Answered
nonzero m and d coefficients for Matlab PDE
Refer to this documentation: https://www.mathworks.com/help/pde/ug/pde.pdemodel.specifycoefficients.html#bu7pwf5 d has to be a...

3 months ago | 0

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Answered
How to indicate the number of nodes and elements of mesh of PDE problem in command line? (the function pdeplot can't do this)
Try using: pdemesh(modelM,'NodeLabels','on') Does it not show labels of node for you?

3 months ago | 0

Answered
PDE Thermal model computation speed
Hi Juan, Nonconstant BC would take longer than constant BC. However, the increase you are observing seems abnormal, given that...

3 months ago | 0

Answered
How to incorporate a 3D mesh in [p,e,t] format on a PDE thermal model?
You can attempt to use geometryFromMesh function to import geometry as a mesh (also retain the original mesh). Regards, Ra...

4 months ago | 0

Answered
How to apply external heat flux to a surface with specified "emissivity" boundary conditions in MATLAB R2018 PDE Toolbox?
You can specify all heat fluxes on that BC with a single function call, like: thermalBC(thermalmodelT,'Edge',2,'HeatFlux',@So...

4 months ago | 0

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Answered
How to impose a variable temperature distribution for one edge of a rectangular plate while keeping the temperatures of other three edges same and constant?
Hi Anik, Define a function to model variation of temperature and use it in BC specification: tFunc = @(region,state) 30.*sin(...

5 months ago | 1

| accepted

Answered
Assigning faces or cells fro meshes created by distmesh
Hello Lewis, To get multiple subdomains into PDE Toolbox you need to use the four argument format of the geometryFromMesh. Lik...

5 months ago | 0

Answered
Compute Craig Bampton model reduction using structural PDE toolbox
Hi Alberto, I see have asked this question a while ago, hope it is still relevant to you. Could you elaborate your use case a ...

5 months ago | 0

Answered
How to export things from pdetool?
You can export gometry related information from pdetool from the 'Draw' menu, last option. You might also consider other geomet...

6 months ago | 0

Answered
Control mesh size on the faces of a 3D Structural Model
Local mesh refinement is currently not availbale in PDE Toolbox.

6 months ago | 0

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