plotting wall shear stress
 

Hi, all:

After calculating an air flow field, I tried to display the wall shear stress along a wall. The vector display showed clearly that there's a region of negative wall shear (where the flow recirculation occured), but the xy-plot of wall shear showed me all non-negative values. Could anyone tell me why this happened? Is it because that Fluent only gives the magnitude when doing xy plot?

Thanks a lot.

Ellen

same model,different result!!!why?
 

Hello,everybody.Now I am solving flowfield around airfoil NACA0012,which has attack angle of 4degrees and a Ma number of 0.8.For the first time,I use a C-type grid,the second time,a hydrid one with a rectangular farfield boundery(C-tyep around the airfoil,and triangular ). But the second Cd doubled the first one, whereas there is a little difference between Cl and Cm. Can anybody tell me why?