Mysterious 1.4 coefficient in UBLDef

[damiendavidINSA]

Hello,

The computation of the advection heat flux in the UBL involves a coefficient "1.4" that I can not explain.

The 1.4 coefficient occurs in the file uwg/UBLDef.py, lines 101, 105, 130, 136:

uwg/uwg/UBLDef.py

Line 101 in ee85e1d

advCoef = self.orthLength*eqWind * simTime.dt / self.urbArea * 1.4

uwg/uwg/UBLDef.py

Line 105 in ee85e1d

advCoef = self.perimeter * u_circ * simTime.dt / self.urbArea * 1.4

uwg/uwg/UBLDef.py

Line 130 in ee85e1d

advCoef1 = 1.4 * dt / paralLength / h_UBL * intAdv1

uwg/uwg/UBLDef.py

Line 136 in ee85e1d

advCoef2 = 1.4 * dt / paralLength / h_UBL * intAdv2

Has anyone any idea about the physical significance of the 1.4 coefficient?

Regards