Hydrodynamic materials are used only for the 2D and 3D hydrodynamic elements. This material model is used to model the structural properties of fluids. The hydrodynamic material properties are listed below. Depending on the element type, analysis type and loads, not all the material properties may be required. In addition to these properties, it may be necessary to define some Isotropic Material Properties.
Bulk Modulus
The bulk modulus of elasticity relates the pressure or stress required for a change in volume. For a fluid, it would equal P 0 /(ΔV/V 0 ) where P 0 is the hydrostatic pressure, ΔV is the change in volume, and V 0 is the original volume. For a solid, the bulk modulus can be found from the equation E/[3*(1-2*v)] where E is the modulus of elasticity of the material and v is Poisson's ratio of the material. The higher the modulus is, the more incompressible the material. It should be noted that the sound (wave) speed within a material increases with incompressibility.