Really slow convergence with my simulation

[waaizhaq]

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Question

Hello,

I'm trying to run natural convection flow through a fuel bundle flow channel, but whenever I start the simulation it either converges at the timestep, around 0 seconds, or it doesn't converge when it increases the 'dt.' It just stays around the initial timestep. I'm not sure what's causing this or how to solve it. Could it be my mesh quality?

Here's my moose input:
flow_across_bundle.txt

Additional information

Mesh size and type: 5000, hex
Reynolds number:
Discretization (finite element CG/DG, finite volume, etc): FV
Models (turbulence, porous media, etc): natural convection
Solver method (fully coupled, segregated, multiapps, etc):
Base input you started from:

[GiudGiud]

Hello

you'll want to start with a simpler system / simpler mesh.
The mesh looks very coarse, but refining it wont let you troubleshoot the issue

Guillaume

[waaizhaq]

By simpler do you mean create a 2D mesh? Because I was wanting to model the flow around 4 rods.

Thanks!

[GiudGiud]

2D seems great. Very simple.

[waaizhaq]

Got it. I'll change my input to only vary in 2D and see if it works.

Thank you!