In SimHydraulics, basic fluid properties such as density, viscosity, and liquid bulk modulus are assumed to be constant during simulation run. Their values are computed before the simulation depending on the specified temperature. All of them are assumed to remain constant with pressure changes except fluid bulk modulus. The bulk modulus of the fluid, which is treated as a mixture of liquid and non-dissolved gas, varies with pressure and this relationship is described in the documentation for the Constant Chamber block.
As a workaround, consider the following submission on MATLAB Central:
