Takes into account along with the compressibility of the pressure fluid also the elasticity of the surrounding components as well as the connection line between the valve and .
The equivalent bulk modulus is not a constant magnitude, but instead a function of the pressure. This situation applies above all for the low pressure range. The reason for this relationship is the mostly unavoidable undissolved air content of the oil as well as the non-linear expansion of hoses (Figure E 35).
Figure E 35: Equivalent bulk modulus for a pipe and hose