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Numerical Instability

Posted Aug 3, 2024, 8:24 p.m. EDT Fluid & Heat, Heat Transfer, Porous Media Flow Version 5.4 0 Replies

Ignatius Tommy Pratama

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Hi everyone! I am a relatively new user trying to simulate the heat transfer in an energy raft foundation. However, I often encounter numerical instability in my 3-D simulation. The temperature distribution around the raft foundation is not what I expected. As shown in the figure attached, some areas can have high temperatures out of nowhere. The expected result is also attached to this post with a dark blue color surrounding the raft foundation. I have tried to adjust my boundary condition, refine the mesh, and adjust the time stepping in the time-dependent solver by changing the Maximum Step Constraint and Maximum Step to Strict and 0.1 days (i.e., equals the assigned time interval/step), respectively. However, the problem still exists. I am wondering what approach I can take to fix this issue.

FYI: I use Heat Transfer in Porous Media, Darcy's Law, and Heat Transfer in Pipes modules in my simulation. I also do coupled analysis. I use Darcy's law velocity in the Heat Transfer in Porous Media, and the Heat Transfer in Porous Media is used by the Heat Transfer in Pipes module as the ambient temperature.

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