NU_CYL_PL64

This function computes the average Nusselt number for forced crossflow over a single cylinder using the 1964 Perkins-Leppert update. Reynolds and Prandtl numbers are evaluated at free-stream conditions, with an optional viscosity-ratio wall correction.

Nu = \left(0.31Re^{0.5} + 0.11Re^{0.67}\right)Pr^{0.4}\left(\frac{\mu}{\mu_w}\right)^{0.25}

Excel Usage

=NU_CYL_PL64(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: Perkins-Leppert 1964 example case

Inputs:

Re	Pr
6071	0.7

Excel formula:

=NU_CYL_PL64(6071, 0.7)

Expected output:

53.6177

Example 2: Perkins-Leppert 1964 with viscosity correction

Inputs:

Re	Pr	mu	muw
22000	3	0.0014	0.0009

Excel formula:

=NU_CYL_PL64(22000, 3, 0.0014, 0.0009)

Expected output:

234.44

Example 3: Perkins-Leppert 1964 at low Reynolds

Inputs:

Re	Pr
1500	1.2

Excel formula:

=NU_CYL_PL64(1500, 1.2)

Expected output:

28.8017

Example 4: Perkins-Leppert 1964 at high Prandtl

Inputs:

Re	Pr
80000	15

Excel formula:

=NU_CYL_PL64(80000, 15)

Expected output:

885.495

Python Code

Show Code

from ht.conv_external import Nu_cylinder_Perkins_Leppert_1964 as ht_Nu_cylinder_Perkins_Leppert_1964

def Nu_cyl_PL64(Re, Pr, mu=None, muw=None):
    """
    Calculate the Nusselt number for crossflow across a single cylinder using the Perkins-Leppert 1964 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_Perkins_Leppert_1964(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).