1//! Viscous constitutive models. 2 3use crate::math::Scalar; 4 5/// Required methods for viscous constitutive models. 6pub trait Viscous { 7 /// Returns the bulk viscosity. 8 fn bulk_viscosity(&self) -> Scalar; 9 /// Returns the shear viscosity. 10 fn shear_viscosity(&self) -> Scalar; 11}