NU_EXT_HORZ_PLATE

This function computes the Nusselt number for external forced convection along a horizontal flat plate. It can use an explicitly selected correlation or automatically choose a laminar or turbulent method based on a transition Reynolds number.

In automatic mode, a piecewise method selection is used:

Nu = \begin{cases} f_{\text{lam}}(Re, Pr), & Re < Re_{\text{transition}} \\ f_{\text{turb}}(Re, Pr), & Re \ge Re_{\text{transition}} \end{cases}

Excel Usage

=NU_EXT_HORZ_PLATE(Re, Pr, L, x, plate_method, laminar_pref, turbulent_pref, Re_transition)
  • Re (float, required): Reynolds number with respect to plate length (-).
  • Pr (float, required): Prandtl number with respect to bulk properties (-).
  • L (float, optional, default: null): Plate length (m).
  • x (float, optional, default: null): Plate distance for local calculation (m).
  • plate_method (str, optional, default: null): Correlation method name (-).
  • laminar_pref (str, optional, default: “Baehr”): Preferred laminar correlation name (-).
  • turbulent_pref (str, optional, default: “Schlichting”): Preferred turbulent correlation name (-).
  • Re_transition (float, optional, default: 500000): Reynolds number for laminar-turbulent transition (-).

Returns (float): Nusselt number with respect to plate length (-).

Example 1: Horizontal plate turbulent example

Inputs:

Re Pr
10000000 0.7

Excel formula:

=NU_EXT_HORZ_PLATE(10000000, 0.7)

Expected output:

11497

Example 2: Horizontal plate laminar range

Inputs:

Re Pr
80000 0.71

Excel formula:

=NU_EXT_HORZ_PLATE(80000, 0.71)

Expected output:

167.545

Example 3: Horizontal plate with explicit method

Inputs:

Re Pr plate_method
300000 0.9 Baehr

Excel formula:

=NU_EXT_HORZ_PLATE(300000, 0.9, "Baehr")

Expected output:

351.137

Example 4: Horizontal plate with custom transition

Inputs:

Re Pr Re_transition
600000 1.1 200000

Excel formula:

=NU_EXT_HORZ_PLATE(600000, 1.1, 200000)

Expected output:

1637.17

Python Code

Show Code 
from ht.conv_external import Nu_external_horizontal_plate as ht_Nu_external_horizontal_plate

def Nu_ext_horz_plate(Re, Pr, L=None, x=None, plate_method=None, laminar_pref='Baehr', turbulent_pref='Schlichting', Re_transition=500000):
    """
    Calculate the Nusselt number for forced convection across a horizontal plate.

    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 plate length (-).
        Pr (float): Prandtl number with respect to bulk properties (-).
        L (float, optional): Plate length (m). Default is None.
        x (float, optional): Plate distance for local calculation (m). Default is None.
        plate_method (str, optional): Correlation method name (-). Valid options: Baehr, Churchill Ozoe, Schlichting, Kreith. Default is None.
        laminar_pref (str, optional): Preferred laminar correlation name (-). Valid options: Baehr, Churchill Ozoe. Default is 'Baehr'.
        turbulent_pref (str, optional): Preferred turbulent correlation name (-). Valid options: Schlichting, Kreith. Default is 'Schlichting'.
        Re_transition (float, optional): Reynolds number for laminar-turbulent transition (-). Default is 500000.

    Returns:
        float: Nusselt number with respect to plate length (-).
    """
    try:
        return ht_Nu_external_horizontal_plate(
            Re=Re,
            Pr=Pr,
            L=L,
            x=x,
            Method=plate_method,
            laminar_method=laminar_pref,
            turbulent_method=turbulent_pref,
            Re_transition=Re_transition,
        )
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Reynolds number with respect to plate length (-).
Prandtl number with respect to bulk properties (-).
Plate length (m).
Plate distance for local calculation (m).
Correlation method name (-).
Preferred laminar correlation name (-).
Preferred turbulent correlation name (-).
Reynolds number for laminar-turbulent transition (-).