atl_spectral_visc_type Derived Type

type, public :: atl_spectral_visc_type

Datatype representing the spectral viscosity stabilization.

The spectral viscosity stabilzation applies a damping of the modal coefficients (in spectral space). The filter applies an expontential damping:

If the modal expansion is given by: $u(x) = \sum_{k=0}^N u_k L_k(x)$

The spectral viscosity applies the following damping: $u(x) = \sum_{k=0}^N \sigma_k u_k L_k(x)$

The damping coefficient $\sigma_k$ is given by: $\sigma_k = exp( -\alpha (|k|_{L2}/|cut_order|_{L2})^{order} )$