I've been developing a curvilinear FVM code. So far I've implemented the PPM scheme and am looking into adding WENO schemes. So far I've been discretizing the grid metrics using a second-order central.
For the WENO scheme will I need to use a higher-order scheme (5th order?) for the grid metrics. When I use the WENO scheme in curvilinear coordinates I get numerical oscillations, which makes me believe it has to do with the grid metrics. I've implemented the WENO scheme on a purely cartesian grid to verify the implementation was done right.