Interface
#include <codecogs/engineering/heat_transfer/convection/nusselt_flat.h>
using namespace Engineering::Heat_Transfer::Convection;
| double | Nusselt_flat (double Pr, double Re)[inline] Returns the Nusselt number for a fluid going over a flat surface. |
 | Real | cc_convectionNusselt_flat (Real Pr, Real Re) This function is available as a Microsoft Excel add-in. |
Function Documentation
This module calculates the Nusselt number for a fluid which flows over a flat surface, the flow being either laminar or turbulent. The fluid must keep its state of matter during the heat transfer process.
The formulae for each case are given by
and
where

is the Reynolds number and

is the Prandtl number of the fluid. If the Reynolds number is less than 2000 the flow is considered laminar, while if it is greater than 4000 the flow is considered turbulent.
In the diagram below the relation between the velocity of the fluid and its corresponding Reynolds number is shown, as well as the unit heat flow in the laminar, unpredictable and turbulent cases.
Example:
- The following code calculates the Nusselt number for Ethylene Glycol at 17 degrees Celsius, considering both the laminar and turbulent cases.
#include <codecogs/engineering/heat_transfer/convection/nusselt_flat.h>
#include <stdio.h>
int main()
{
double Pr = 233.7745380139, Re1 = 1700, Re2 = 4200;
printf("\nEthylene Glycol at 17 deg. Celsius\n\n");
printf("Re = %.2lf (laminar flow)\n", Re1);
printf("Nu = %.4lf\n\n",
Engineering::Heat_Transfer::Convection::Nusselt_flat(Pr, Re1));
printf("Re = %.2lf (turbulent flow)\n", Re2);
printf("Nu = %.4lf\n\n",
Engineering::Heat_Transfer::Convection::Nusselt_flat(Pr, Re2));
return 0;
}
Output
Ethylene Glycol at 17 deg. Celsius
Re = 1700.00 (laminar flow)
Nu = 211.1873
Re = 4200.00 (turbulent flow)
Nu = 17041.1869
Parameters:
| Pr | the Prandtl number of the fluid |
| Re | the Reynolds number of the fluid |
Returns:
- the Nusselt number of the fluid with given parameters
References:
- Dan Stefanescu, Mircea Marinescu - "Termotehnica"
Authors:
- Grigore Bentea, Lucian Bentea (November 2006)
Source Code:
-
Last Modified: 12 Nov 07 @ 13:45 Page Rendered: 2008-05-09 13:48:58
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