A template for a typical Stokes Solver sif-entry:
Solver 1 Equation = "Navier-Stokes" Stabilization Method = String Bubbles Flow Model = Stokes Linear System Solver = Direct Linear System Direct Method = umfpack Nonlinear System Max Iterations = 100 Nonlinear System Convergence Tolerance = 1.0e-5 ! first 5 iterations or convergence < 1.e-2 before moving from ! Picard to Newton Nonlinear System Newton After Iterations = 5 Nonlinear System Newton After Tolerance = 1.0e-02 Nonlinear System Relaxation Factor = 1.00 ! reset newton to false each new time step Nonlinear System Reset Newton = Logical True Steady State Convergence Tolerance = Real 1.0e-3 End
The Newton linearisation gives a quadratic convergence whereas Picard is linear, at least some Picard iterations are however required.