[Tarak]

Hi,

The standard porosity models implemented in OpenFOAM, e.g DarcyForchheimer and powerLaw, identify the regions in the computational domain where the body force term has to be added using the cellZone supplied by the user. This offers a very convenient way to prescribe the porous regions in the domain.

But, in the newly added "powerLawLopesdaCosta porosity model", instead of utilizing user-prescribed cellZones, the model explicitly identifies the cells in the porous region using a convoluted process (using information from surface files representing the top and bottom regions of the porous region, and generating cellZone while running the model). Maybe, there's an option to not create a new cellZone if there's already an existing one (created by the user manually, corresponding to the else branch of if(zoneID == -1), but it still requires surface files corresponding to the top and bottom of the porous regions to run the model.

I'm not sure why this length process has been pursued for the powerLawLopesdaCosta porosity model, is it only to allow the porosity surface area per unit volume parameter (Sigma) to be a function of height?

[HPE]

i think the term 'porosity' for that model is very unfortunate. that term should be 'canopy' instead, since that particular model is for modelling vegetation canopy of atmospheric boundary layers. I dont think therefore this model relates to what other porosity models do. i might be wrong as well, but quite unlikely

hope it helps.