[Gfs-devel] understanding a line in gfs_face_advection_flux()

[Manoj Kumar Tripathi]

In advection.c, in the function,
 gfs_face_advection_flux (const FttCellFace * face, const GfsAdvectionParams * par)

the expression which calculates flux of a tracer is written as:
flux = gfs_domain_face_fraction (par->v->domain, face)*GFS_FACE_NORMAL_VELOCITY (face)*par->dt*
    gfs_face_upwinded_value (face, GFS_FACE_UPWINDING, NULL)/ftt_cell_size (face->cell);

As explained in the "Gerris programming for dummies" page (http://gfs.sourceforge.net/wiki/index.php/Programming_the_Advection_Scheme), this term has a form similar to (u_face * T_face), however I can see the (u_face*u_face*T_face) in the expression in the function referred to, above.

Please tell me if I am wrong, but doesn't  gfs_face_upwinded_value (face, GFS_FACE_UPWINDING, NULL) return GFS_FACE_NORMAL_VELOCITY (face), in this case?

Thank you.

--

Manoj Kumar Tripathi

email: ma...@iith.ac.in