NU_EXT_CYL_METHODS

This function returns the available forced-convection cylinder correlations for given Reynolds and Prandtl conditions. When range checking is enabled, only methods applicable to the supplied input domain are returned.

Conceptually, it filters the candidate set of methods:

\mathcal{M}_{\text{valid}} = \{m \in \mathcal{M} \mid \text{constraints}_m(Re, Pr, Pr_w, \mu, \mu_w)\}

Excel Usage

=NU_EXT_CYL_METHODS(Re, Pr, Prw, mu, muw, check_ranges)

Re (float, required): Reynolds number with respect to cylinder diameter (-).
Pr (float, required): Prandtl number at either free stream or wall temperature (-).
Prw (float, optional, default: null): Prandtl number at wall temperature (-).
mu (float, optional, default: null): Viscosity at free stream temperature (Pa*s).
muw (float, optional, default: null): Viscosity at wall temperature (Pa*s).
check_ranges (bool, optional, default: true): Whether to return only correlations suitable for the inputs (-).

Returns (list[list]): 2D array of available correlation method names.

Example 1: Cylinder methods with default inputs

Inputs:

Re	Pr
0.72	10000000

Excel formula:

=NU_EXT_CYL_METHODS(0.72, 10000000)

Expected output:

Sanitjai-Goldstein
Churchill-Bernstein
Fand
McAdams

Example 2: Cylinder methods in air

Inputs:

Re	Pr
10000	0.71

Excel formula:

=NU_EXT_CYL_METHODS(10000, 0.71)

Expected output:

Sanitjai-Goldstein
Churchill-Bernstein
Fand
McAdams

Example 3: Cylinder methods with wall Prandtl

Inputs:

Re	Pr	Prw
8000	0.7	0.69

Excel formula:

=NU_EXT_CYL_METHODS(8000, 0.7, 0.69)

Expected output:

Sanitjai-Goldstein
Churchill-Bernstein
Fand
McAdams
Zukauskas

Example 4: Cylinder methods without range checking

Inputs:

Re	Pr	check_ranges
500000	1.2	false

Excel formula:

=NU_EXT_CYL_METHODS(500000, 1.2, FALSE)

Expected output:

Sanitjai-Goldstein
Churchill-Bernstein
Fand
McAdams

Python Code

Show Code

from ht.conv_external import Nu_external_cylinder_methods as ht_Nu_external_cylinder_methods

def Nu_ext_cyl_methods(Re, Pr, Prw=None, mu=None, muw=None, check_ranges=True):
    """
    List available correlations for external cylinder forced convection.

    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 either free stream or wall temperature (-).
        Prw (float, optional): Prandtl number at wall temperature (-). Default is None.
        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.
        check_ranges (bool, optional): Whether to return only correlations suitable for the inputs (-). Default is True.

    Returns:
        list[list]: 2D array of available correlation method names.
    """
    try:
        methods = ht_Nu_external_cylinder_methods(
            Re=Re,
            Pr=Pr,
            Prw=Prw,
            mu=mu,
            muw=muw,
            check_ranges=check_ranges,
        )
        return [[method] for method in methods]
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Re *

Reynolds number with respect to cylinder diameter (-).

Pr *

Prandtl number at either free stream or wall temperature (-).

Prw

Prandtl number at wall temperature (-).

Viscosity at free stream temperature (Pa*s).

muw

Viscosity at wall temperature (Pa*s).

check_ranges

Whether to return only correlations suitable for the inputs (-).