Alternating plus and minus signs in the results
 

Hi All,

This is maybe too general a question.

My results showed in the attachment is the derivatives of the flow field, row is the x direction and column y direction.
You see there are the signs alternating every grid point in the y direction. I used compact scheme to calculate the derivative.

I want to ask what could be the reason for this kind of outcome. I know that dispersion error could generate some alternating signs along the y=0 line, for example.

Thanks,
Jo