10.4 Stability analysis Session file configuration

The type of equation which is to be solved is specified through the EqType option in the session file. This can be set to any of the following:

Equation to solve
∂u∂′t + L(U,u′) = -∇p + ν∇2u′

Equation Type Dimensions Projections Algorithms
UnsteadyNavierStokes 2D, Quasi-3D Continuous VCS,DS

10.4.1 Solver Info

10.4.2 Parameters

The following parameters can be specified in the PARAMETERS section of the session file:

10.4.3 Functions

When using the direct solver for stability analysis it is necessary to specify a Forcing function “StabilityCoupledLNS” in the form:

2   <FORCE TYPE="StabilityCoupledLNS"> 
3   </FORCE> 

This is required since we need to tell the solver to use the existing field as a forcing function to the direct matrix inverse as part of the Arnoldi iteration.

Note: Examples of the set up of the direct solver stability analysis (and other incompressible Navier-Stokes solvers) can be found in the regression test directory NEKTAR/solvers/IncNavierStokesSolver/Tests. See for example the files PPF_R15000_ModifiedArnoldi_Shift.tst and PPF_R15000_3D.xml noting that some parameters are specified in the .tst files.