All Questions
67 questions
1
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213
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BTCS-like method for heat conduction in unstructured triangular grid
I want to write a simple simulation for heat conduction in a unstructured triangular mesh.
I already made it work for a structured rectangular grid with the ADI method, but now I need more complex ...
- 23
1
vote
0
answers
73
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How to get a theoretical background in nonlinear, coupled FEM systems
I'm currently developing simulations for coupled, nonlinear, multi-region systems. Basically, I use the Finite Element Method (FEM) to model each physical quantity in each region. The obtained ...
- 1,463
1
vote
0
answers
67
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Help about Fluid-Fluid coupling techniques
I need a little help and advice with a project I want to do: the idea is to "couple" (I don't know whether I can call it like this) a conservative Navier-Stokes Solver (Fractional-step, 2nd order FDM) ...
- 251
0
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1
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148
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Problem with my Octave code (unsteady heat equation with FEM)
I want help with my Octave code regarding the unsteady heat equation.
My geometry and mesh are generated with FreeFEM++, so there is no problem with that (I tried it with the steady problem with no ...
- 3
0
votes
2
answers
1k
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(FEM) 1D time-dependent heat equation convergence problem
I'm simulating a simple 3-node bar with convection BCs at the edges to validate my FEM code. The following data was used:
Initial temperature = 25 ºC
Temperature surrounding the rod = 10 ºC
Thermal ...
user30551
0
votes
1
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143
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How to get a normalized gradient with FreeFem++?
I am trying to use FreeFem++ to solve the heat geodesics algorithm.
The algorithm is:
solve $\dot u = \Delta u$ at a specific time $t$.
compute $X = \frac{\nabla u_t}{|\nabla u_t|}$
solve $\Delta\phi ...
- 379
0
votes
1
answer
214
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Incorporating heat flux into Laplace Equation
I need to find the temperature distribution of a square plate using the Laplace equation by using FDM:
$$ \frac{d^2T}{dx^2} + \frac{d^2T}{dy^2} = 0$$
But there is a heat flux entering from the top ...
- 145
0
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1
answer
853
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Heat equation with Neumann and Dirichlet conditions on same boundary
I am looking at numerical solutions to the heat equation with Dirichlet and Neumann conditions on the same boundary. That is $u(x,t)$ satisfying
$$
u_t = u_{xx}\,, \quad x \in[0,1]\,, \quad t>0\,,...
- 531
0
votes
1
answer
583
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Implementing odespy for system of PDEs
After trying to use RK4 to solve the below system of equations, it appears the output had large and fast oscillations even with an adaptive time step I incorporated using the Cash-Karp method. I am ...
- 568
0
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1
answer
51
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Produce vertex displacements from volumetric shrinkage data on unstructured meshes
I was wondering what would be an efficient way to produce compatible displacements for mesh nodes/vertices if the computed data is volume shrinkage of each element/cell in the unstructured mesh?
...
- 1,413
0
votes
1
answer
614
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Heat diffusion - Is this the correct approach to include Newmann boundary conditions?
Thank you for looking at this problem. Is this the correct approach to include neumann boundary conditions? With this solution temperature is not correct, and there´s no diffusion. The model seems ...
- 3
0
votes
1
answer
68
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Modeling Diodes in Autodesk CFD
I'm extremely new to Autodesk CFD, and I'm working on a project that deals with diodes heating up and cooling down based on a fixed temperature regulated by a temperature switch. Basically, I have a ...
0
votes
1
answer
99
views
Solving the diffusion/heat equation for a randomly distributed set of points in 3D
In this problem I am trying to solve, I have a messy set of points distributed in 3D space, each with a defined temperature. If I would want to calculate the heat transfer scenario in this system, how ...
- 121
0
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0
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128
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Heat Equation for fast source with FiPy
I'm trying to solve the following differential equation with FiPy, basically laser irradiation on a surface
$$
\rho_{s}C_{p,s}\frac{\partial T}{\partial t} = k_{s}\frac{\partial^{2}T}{\partial x^{2}} +...
- 11
0
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0
answers
38
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Thermo Hydraulic Mechanical modeling of energy wall slab in Comsol multiphysics
I am currently working on a complex simulation project involving an energy wall slab, and I need assistance in accurately modeling and validating it using COMSOL Multiphysics. Here are the details of ...
0
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0
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49
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Finite elements algorith for a fluid in a tube with an elastic obstacle (Fluid-Solid coupling)
I want to solve the model of a tube with an elastic obstacle, something like a simple model of an vessel with a valve. The fluid is given by an evolutionary incompressible Navier--Stokes equations, ...
- 527
0
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0
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44
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Isolated solving of coupled system of PDE [duplicate]
I would like to solve 3 differential equations for 3 unknowns. So I wrote a MATLAB code, which solves (using the '\' operator) these equation using a linear system of equations (in which the 3 ...
- 71