display and roughness

nicolas

I have two questions : One about roughness in simulation : I use an realisable K epsilon model with no equilibrum wall fonction.I have some problems with convergence.I m not sure if it dues to the mesh size near the wall.What must the value of Y+ or y* be near the wall? How to display it ? The second question is about display : I have a big volume with a restriction in a pipe. Restriction involves big velocity gradient.In comparaison in the big part of the volume the gradient is smaller, so I can visualize it? Is it possible to adapt the range of velocity for the display (I already use 100 colors and the log visualisation only works with velocity vectors and not with contours, is it normal?) Thanks very much.