Functions for convective heat transfer
Information
This package contains functions that are used in the
package
Buildings.HeatTransfer.
Package Content
| Name |
Description |
 HeatFlux
|
Correlations for convective heat flux |
 windDirectionModifier
|
Wind direction modifier that is used to compute the wind-driven convective heat transfer coefficient |
Wind direction modifier that is used to compute the wind-driven convective heat transfer coefficient
Information
Function that outputs 1 if the incidence angle is below 100 degrees, and
0.5 otherwise.
The implementation is once continuously differentiable in its input arguments.
See
Buildings.HeatTransfer.Examples.ExteriorConvection
for an example that uses this function.
Inputs
| Type | Name | Default | Description |
|---|
| Angle | azi | | Surface azimuth [rad] |
| Angle | dir | | Wind direction (0=wind from North) [rad] |
Outputs
| Type | Name | Description |
|---|
| Real | W | Wind direction modifier |
Modelica definition
function windDirectionModifier
"Wind direction modifier that is used to compute the wind-driven convective heat transfer coefficient"
input Modelica.SIunits.Angle azi
"Surface azimuth";
input Modelica.SIunits.Angle dir(min=0, max=2*Modelica.Constants.pi)
"Wind direction (0=wind from North)";
output Real W
"Wind direction modifier";
protected
constant Modelica.SIunits.Angle lee =
Modelica.SIunits.Conversions.from_deg(100);
constant Real cosLee =
Modelica.Math.cos(lee);
algorithm
// The wind direction is defined in TMY3 as dir=0 if from North, and 0 <= dir < 2*pi
// Hence, we subtract pi to redefine dir=0 as wind coming from the south.
// This simplifies the implementation since a surface azimuth is defined as azi=0
// if the surface is south-facing
W:=
Buildings.Utilities.Math.Functions.spliceFunction(
pos=0.5,
neg=1,
x=cosLee-
Modelica.Math.cos(azi+Modelica.Constants.pi-dir),
deltax=0.05);
end windDirectionModifier;
Automatically generated Thu Jun 19 10:57:30 2014.
