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Fluid flow simulation hanging (5.3)

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Hello everyone,

I am new to COMSOL, and I'm trying to model fluid flow over a sphere. For some reason, I keep getting the following error:

Failed to find a solution. Maximum number of Newton iterations reached. Returned solution is not converged. Not all parameter steps returned.

what's interesting to note is the progress bar appears as if it is about to finish, then regresses again. It does this for a couple of time before reaching a conclusion.

I changed the number of Newton iterations by changing max number of iterations, but I am not sure what else to change. I have attached my file to this post. Any help would be appreciated.



1 Reply Last Post 15 apr 2019, 08:43 GMT-4
Jeff Hiller COMSOL Employee

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Posted: 5 years ago 15 apr 2019, 08:43 GMT-4
Updated: 5 years ago 15 apr 2019, 09:33 GMT-4

Hi Anmol,

The Reynolds number for the flow in your file is on the order of 1e5, so I would not expect the flow to be laminar. If the flow you are trying to model is in fact laminar, then the inlet velocity must be smaller than you set it up in your model, or the dimensions smaller, or the fluid not air. If inlet velocity, dimensions and material properties are all set correctly, then you need to model this as a turbulent flow. This can be done with the CFD Module or the Heat Transfer Module, see the Specification Chart for fluid flows.

Best,

Jeff

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Jeff Hiller
Hi Anmol, The Reynolds number for the flow in your file is on the order of 1e5, so I would not expect the flow to be laminar. If the flow you are trying to model is in fact laminar, then the inlet velocity must be smaller than you set it up in your model, or the dimensions smaller, or the fluid not air. If inlet velocity, dimensions and material properties are all set correctly, then you need to model this as a turbulent flow. This can be done with the CFD Module or the Heat Transfer Module, see the [Specification Chart for fluid flows](https://www.comsol.com/products/specifications/fluid-flow/). Best, Jeff

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