The Linearized Navier–Stokes Model adds the governing equations, and defines the background mean flow and the fluid properties. Gradient term suppression stabilization (advanced physics option) can be selected, if needed. See the Linearized Navier–Stokes Model for The Linearized Navier–Stokes, Frequency Domain Interface for details.

Define the Propagation direction of the computed modes. The default is to use the surface physics normal (components lnsbm.nx, lnsbm.ny, and lnsbm.nz) that points out of domains.