How to discretize the pressure gradient for curvilinear MAC grids (Q1186203)

Curvilinear coordinates present certain difficulties for incompressible flow calculations with marker-and-cell (MAC) grids. Among these are questions regarding the discretization of derivatives in the pressure gradient, which should remain irrotational while maintaining conservation of mass. This paper examines alternative approximations for pressure derivatives next to the boundaries and for coordinate derivatives throughout the flow. Several combinations of alternatives are tested for their ability to remove continuity violations, without adding vorticity, in channels that have been fitted with nonorthogonal MAC grids.