CAVITATION

Calculates the Cavitation number to measure how close a flowing liquid is to vapor-pressure-driven cavitation conditions.

Excel Usage

=CAVITATION(P, Psat, rho, V)

• P (float, required): Internal pressure in Pascals (Pa)
• Psat (float, required): Vapor pressure in Pascals (Pa)
• rho (float, required): Fluid density in kilograms per cubic meter (kg/m³)
• V (float, required): Fluid velocity in meters per second (m/s)

Returns (float): Cavitation number (float), or error message string.

Example 1: Cavitation number at moderate liquid velocity

Inputs:

P	Psat	rho	V
200000	10000	1000	10

Excel formula:

=CAVITATION(200000, 10000, 1000, 10)

Expected output:

3.8

Example 2: Higher velocity with slightly lower density

Inputs:

P	Psat	rho	V
250000	15000	950	20

Excel formula:

=CAVITATION(250000, 15000, 950, 20)

Expected output:

1.23684

Example 3: Lower pressure difference with dense liquid

Inputs:

P	Psat	rho	V
120000	10000	998	8

Excel formula:

=CAVITATION(120000, 10000, 998, 8)

Expected output:

3.44439

Example 4: High-pressure dense liquid flow

Inputs:

P	Psat	rho	V
300000	50000	1020	15

Excel formula:

=CAVITATION(300000, 50000, 1020, 15)

Expected output:

2.17865

Python Code

Show Code

from fluids.core import Cavitation as fluids_cavitation

def cavitation(P, Psat, rho, V):
    """
    Calculate the Cavitation number (Ca) for a flowing fluid.

    See: https://fluids.readthedocs.io/fluids.core.html#fluids.core.Cavitation

    This example function is provided as-is without any representation of accuracy.

    Args:
        P (float): Internal pressure in Pascals (Pa)
        Psat (float): Vapor pressure in Pascals (Pa)
        rho (float): Fluid density in kilograms per cubic meter (kg/m³)
        V (float): Fluid velocity in meters per second (m/s)

    Returns:
        float: Cavitation number (float), or error message string.
    """
    try:
        P = float(P)
        Psat = float(Psat)
        rho = float(rho)
        V = float(V)
    except (ValueError, TypeError):
        return "Error: All parameters must be numeric values."

    if V == 0:
        return "Error: velocity (V) must be nonzero."
    if rho == 0:
        return "Error: density (rho) must be nonzero."

    try:
        result = fluids_cavitation(P, Psat, rho, V)
    except Exception as e:
        return f"Error: {str(e)}"
    return result

Online Calculator

P *

Internal pressure in Pascals (Pa)

Psat *

Vapor pressure in Pascals (Pa)

rho *

Fluid density in kilograms per cubic meter (kg/m³)

V *

Fluid velocity in meters per second (m/s)