Function for Nusselt number in horizontal window cavity. The computation is according to TARCOG 2006, except that this implementation computes the Nusselt number as a function that is differentiable in the temperatures.
TARCOG 2006: Carli, Inc., TARCOG: Mathematical models for calculation of thermal performance of glazing systems with our without shading devices, Technical Report, Oct. 17, 2006.
function nusseltHorizontalCavityReduced
extends Modelica.Icons.Function;
input Buildings.HeatTransfer.Data.Gases.Generic gas "Thermophysical properties of gas fill" annotation(
choicesAllMatching = true);
input Real Ra(min = 0) "Rayleigh number";
input Modelica.Units.SI.Temperature T_m "Temperature used for thermophysical properties";
input Modelica.Units.SI.TemperatureDifference dT "Temperature difference used to compute q_flow = h*dT";
input Modelica.Units.SI.Area h(min = 0) = 1.5 "Height of window";
input Real sinTil "Sine of window tilt";
input Real deltaNu(min = 0.01) = 0.1 "Small value for Nusselt number, used for smoothing";
input Real deltaRa(min = 0.01) = 1E3 "Small value for Rayleigh number, used for smoothing";
output Real Nu(min = 0) "Nusselt number";
end nusseltHorizontalCavityReduced;