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error

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i was doing the example given on cylinder flow.i did all steps as explain their,no change.But on solving i got an error


" Error:
Failed to find a solution:
No convergence, even when using the minimum damping factor.
Returned solution has not converged."

i am new with this software. please suggest me a way to remove this error.

please suggest.

3 Replies Last Post 2010年6月29日 GMT-4 02:23

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Posted: 1 decade ago 2010年6月11日 GMT-4 09:52
If you get this error, there must be something wrong with the Boundary Conditions you have specified, double check the boundary conditions.

You can find the Error message and explanation for the same in COMSOL help. I copied the same below:

"No convergence, even when using the minimum damping factor" -The nonlinear solver reduced the damping factor below the minimum value allowed. The solver reduces the damping factor each time a computed step did not lead to a decrease in the error estimate. Make sure the model is well-posed, in particular that there are enough equations and boundary conditions to determine all degrees of freedom. If the model is well-posed, it should have one or more isolated solutions. In that case, the error is probably due to the initial guess being too far from any solution.

Regards,
AndyT
If you get this error, there must be something wrong with the Boundary Conditions you have specified, double check the boundary conditions. You can find the Error message and explanation for the same in COMSOL help. I copied the same below: "No convergence, even when using the minimum damping factor" -The nonlinear solver reduced the damping factor below the minimum value allowed. The solver reduces the damping factor each time a computed step did not lead to a decrease in the error estimate. Make sure the model is well-posed, in particular that there are enough equations and boundary conditions to determine all degrees of freedom. If the model is well-posed, it should have one or more isolated solutions. In that case, the error is probably due to the initial guess being too far from any solution. Regards, AndyT

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Posted: 1 decade ago 2010年6月11日 GMT-4 10:17
did you define a step inflow boundary function? (step function)
did you define and select the inlet and outlet boundary conditions correctly?
did you define a step inflow boundary function? (step function) did you define and select the inlet and outlet boundary conditions correctly?

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Posted: 1 decade ago 2010年6月29日 GMT-4 02:23
i think we have to define pressure at atleast one point for the solution to converge.
i think we have to define pressure at atleast one point for the solution to converge.

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