Bulk Modulus of a Fluid
Bulk Modulus of a Fluid
The bulk modulus measures a fluid’s resistance to compression — important for hydraulics stiffness and water-hammer.
The bulk modulus is K = Δp·V/ΔV. where Δp is the pressure rise, V the original volume and ΔV the volume reduction.
Inputs
dP := 5 MPa=5 MPa
V := 1 L=1e-03 m^3
dV := 0.0025 L=2.5e-06 m^3
Relate pressure rise to fractional volume change.
K := dP·V/dV=2000 MPa
Results
A high bulk modulus (water ≈ 2.2 GPa) means the fluid is nearly incompressible, making hydraulic systems stiff and fast-responding.
Assumptions & limitations
- Isothermal compression.
- Small volume change.
- No dissolved gas.