Buildings.HeatTransfer.Convection.Functions

Name	Description
windDirectionModifier	Wind direction modifier that is used to compute the wind-driven convective heat transfer coefficient
HeatFlux	Correlations for convective heat flux

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.

Inputs

Outputs

Modelica definition

Type	Name	Default	Description
Angle	azi		Surface azimuth [rad]
Angle	dir		Wind direction (0=wind from North) [rad]

Type	Name	Description
Real	W	Wind direction modifier

function windDirectionModifier "Wind direction modifier that is used to compute the wind-driven convective heat transfer coefficient" extends Modelica.Icons.Function; 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) "Angle at which the transition occurs"; constant Real cosLee = Modelica.Math.cos(lee) "Cosine of the angle at which the transition occurs"; 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;