COMSOL Transient Solver

[timjm]

I am currently just running a normal 3D incompressible flow problem in COMSOL 3, and end up with the following error:

Error:
Time 0:
Error in residual computation:
The_relative_error_is_greater_than_the_relative_to lerance
For the direct solver.
Last time step is not converged.

How do I go about resolving this issue?

Thanks.

[akshayvohra]

Hi All,

I am trying to solve a problem where the solutions are expected to be zero for a very long time.

I have refined the mesh with the maximum element size of 0.002 and am using the GMRES method with preconditioning quality of 0.01.

However, inspite of it, the system is unable to process the solution and gives an error for residual computation citing singular matrix as the problem.

Can anyone please suggest some ways to solve the problem?

Akshay