The Anisotropic Acoustics node is used to define a fluid with properties that can be modeled with an effective anisotropic density. The feature can be used to model metamaterials in a homogenized manner or when modeling fibrous materials with anisotropic properties. The material properties are defined through an effective bulk modulus K and an effective density tensor ρ. The density variable can be defined as being isotropic (a scalar), a diagonal tensor, or a symmetric tensor. The resulting (generalized) Helmholtz equation solved in the domain is then

Select the Coordinate system in which the density tensor is defined. The default is the Global coordinate system.

Enter the Effective bulk modulus K (SI unit: Pa) taken From material. For User defined enter other values or expressions for any or all options.

Enter the Effective density ρ (SI unit: kg/m3) taken From material. For User defined enter other values or expressions for any or all options. Also select the representation for the density tensor either Isotropic (the default), Diagonal, or Symmetric.