NU_CYL_WHITAKER

This function computes the average Nusselt number for forced crossflow over a single cylinder using the Whitaker correlation. Reynolds and Prandtl numbers are evaluated at free-stream conditions, and an optional viscosity-ratio correction is included when viscosities are supplied.

Nu_D = \left(0.4Re_D^{0.5} + 0.06Re_D^{2/3}\right)Pr^{0.4}\left(\frac{\mu}{\mu_w}\right)^{0.25}

Excel Usage

=NU_CYL_WHITAKER(Re, Pr, mu, muw)

Re (float, required): Reynolds number with respect to cylinder diameter (-).
Pr (float, required): Prandtl number at free stream temperature (-).
mu (float, optional, default: null): Viscosity at free stream temperature (Pa*s).
muw (float, optional, default: null): Viscosity at wall temperature (Pa*s).

Returns (float): Nusselt number with respect to cylinder diameter (-).

Example 1: Whitaker example case

Inputs:

Re	Pr
6071	0.7

Excel formula:

=NU_CYL_WHITAKER(6071, 0.7)

Expected output:

45.9453

Example 2: Whitaker with viscosity correction

Inputs:

Re	Pr	mu	muw
18000	2	0.0012	0.0008

Excel formula:

=NU_CYL_WHITAKER(18000, 2, 0.0012, 0.0008)

Expected output:

129.266

Example 3: Whitaker at low Reynolds

Inputs:

Re	Pr
50	1

Excel formula:

=NU_CYL_WHITAKER(50, 1)

Expected output:

3.64275

Example 4: Whitaker at high Prandtl

Inputs:

Re	Pr
40000	25

Excel formula:

=NU_CYL_WHITAKER(40000, 25)

Expected output:

394.443

Python Code

Show Code

from ht.conv_external import Nu_cylinder_Whitaker as ht_Nu_cylinder_Whitaker

def Nu_cyl_Whitaker(Re, Pr, mu=None, muw=None):
    """
    Calculate the Nusselt number for crossflow across a single cylinder using the Whitaker correlation.

    See: https://ht.readthedocs.io/en/latest/ht.conv_external.html

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

    Args:
        Re (float): Reynolds number with respect to cylinder diameter (-).
        Pr (float): Prandtl number at free stream temperature (-).
        mu (float, optional): Viscosity at free stream temperature (Pa*s). Default is None.
        muw (float, optional): Viscosity at wall temperature (Pa*s). Default is None.

    Returns:
        float: Nusselt number with respect to cylinder diameter (-).
    """
    try:
        return ht_Nu_cylinder_Whitaker(Re=Re, Pr=Pr, mu=mu, muw=muw)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Re *

Reynolds number with respect to cylinder diameter (-).

Pr *

Prandtl number at free stream temperature (-).

Viscosity at free stream temperature (Pa*s).

muw

Viscosity at wall temperature (Pa*s).