How is the cavitation index calculated?

σ = (P - P_v) / (0.5 × ρ × V²), where P is local pressure (Pa), P_v is vapor pressure (Pa), ρ is fluid density (kg/m³), and V is flow velocity (m/s). Cavitation occurs when σ falls below the critical cavitation number for the geometry.

What is a safe cavitation index value?

Values of σ > 1.0 are generally considered safe. As σ approaches the critical value (σ_c, typically 0.2–0.5 for pumps), cavitation onset is likely. Design guidelines recommend maintaining σ at least 1.5 × σ_c.

Cavitation Index Calculator

Compute the cavitation number (sigma) to assess susceptibility to cavitation in hydraulic machinery and flow passages.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Compute the cavitation number (sigma) to assess susceptibility to cavitation in hydraulic machinery and flow passages. Use the cavitation index result to inform your clinical assessment.

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Frequently Asked Questions

How is the cavitation index calculated?

What is a safe cavitation index value?