CD_MORRISON

Computes the drag coefficient of a smooth sphere from the particle Reynolds number using the Morrison correlation. The model adds viscous, transitional, and high-Re components into one expression.

C_D = f(Re)

Excel Usage

=CD_MORRISON(Re)

• Re (float, required): Particle Reynolds number [-]

Returns (float): Drag coefficient [-], or error message (str) if input is invalid.

Example 1: Reynolds number of 200

Inputs:

Re
200

Excel formula:

=CD_MORRISON(200)

Expected output:

0.767732

Example 2: Reynolds number of 1000

Inputs:

Re
1000

Excel formula:

=CD_MORRISON(1000)

Expected output:

0.484056

Example 3: Reynolds number of 100000

Inputs:

Re
100000

Excel formula:

=CD_MORRISON(100000)

Expected output:

0.424677

Example 4: High Reynolds number (500000)

Inputs:

Re
500000

Excel formula:

=CD_MORRISON(500000)

Expected output:

0.0876769

Python Code

Show Code

from fluids.drag import Morrison as fluids_Morrison

def cd_morrison(Re):
    """
    Calculate drag coefficient of a sphere using the Morrison correlation.

    See: https://fluids.readthedocs.io/fluids.drag.html#fluids.drag.Morrison

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

    Args:
        Re (float): Particle Reynolds number [-]

    Returns:
        float: Drag coefficient [-], or error message (str) if input is invalid.
    """
    try:
      Re = float(Re)
      if Re <= 0:
        return "Error: Re must be positive."

      result = fluids_Morrison(Re=Re)
      if result != result:  # NaN check
        return "Error: Calculation resulted in NaN."
      return float(result)
    except (ValueError, TypeError):
      return "Error: Re must be a number."
    except Exception as e:
      return f"Error: {str(e)}"

Online Calculator

Re *

Particle Reynolds number [-]