NU_CYL_ZUKAUSKAS

This function computes the average Nusselt number for forced crossflow over a single cylinder using the Zukauskas correlation. It selects empirical coefficients by Reynolds-number regime and optionally applies a wall-to-bulk Prandtl correction when wall Prandtl number is provided.

Nu_D = CRe^{m}Pr^{n}\left(\frac{Pr}{Pr_w}\right)^{1/4}

Excel Usage

=NU_CYL_ZUKAUSKAS(Re, Pr, Prw)

Re (float, required): Reynolds number with respect to cylinder diameter (-).
Pr (float, required): Prandtl number at free stream temperature (-).
Prw (float, optional, default: null): Prandtl number at wall temperature (-).

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

Example 1: Zukauskas example case

Inputs:

Re	Pr	Prw
7992	0.707	0.69

Excel formula:

=NU_CYL_ZUKAUSKAS(7992, 0.707, 0.69)

Expected output:

50.5236

Example 2: Zukauskas without wall Prandtl

Inputs:

Re	Pr	Prw
6000	0.7

Excel formula:

=NU_CYL_ZUKAUSKAS(6000, 0.7, )

Expected output:

42.126

Example 3: Zukauskas in laminar range

Inputs:

Re	Pr
30	1.1

Excel formula:

=NU_CYL_ZUKAUSKAS(30, 1.1)

Expected output:

3.02848

Example 4: Zukauskas in turbulent range

Inputs:

Re	Pr
300000	0.9

Excel formula:

=NU_CYL_ZUKAUSKAS(300000, 0.9)

Expected output:

498.733

Python Code

Show Code

from ht.conv_external import Nu_cylinder_Zukauskas as ht_Nu_cylinder_Zukauskas

def Nu_cyl_Zukauskas(Re, Pr, Prw=None):
    """
    Calculate the Nusselt number for crossflow across a single cylinder using the Zukauskas 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 (-).
        Prw (float, optional): Prandtl number at wall temperature (-). Default is None.

    Returns:
        float: Nusselt number with respect to cylinder diameter (-).
    """
    try:
        return ht_Nu_cylinder_Zukauskas(Re=Re, Pr=Pr, Prw=Prw)
    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 (-).

Prw

Prandtl number at wall temperature (-).