Bottom friction

Bottom friction can be provided in three types of file - drag.gr3, or rough.gr3 or manning.gr3. The ‘depth’ value in Gr3 file means \(C_d\), bottom roughness in meters, or Manning’s \(n\), respectively. The 3 files correspond to nchi=0,1,-1.

Bottom friction is a critical parameter in shallow area. Note that the bottom friction parameterizations are very different between 2D and 3D model, and so you cannot use same input. For details please read this article.

Further information can be found here.