Dear all, I would like toimplement a kind of boundary condition on wall. I need to calculatethe velocity gradients over wall elements. The same as the high orderpressure boundary condition, I want to calculate the velocitygradient on each wall elements with the following command: (elmt>PhysDeriv(MultiRegions::DirCartesianMap[j],velocity,grad)) then I extract thegradients value of the boundary with the following command: (elmt->GetEdgePhysVals(boundary,bc,grad,grad boundary ), considerthat I just brought the main sentence and these variables should bedefine. Due to thecoordinates, I know that I could reach the wall nodes with thesecommands, The only problem is with the value of velocity gradients.Regarding the 3d mesh elements, tetrahedron or hexahedron, the valuescan not get their correct value. For example in a hexahedron mesh Iget the wrong values of gradients on the boundaries of the wallelements. Besides, in the tetrahedron mesh, in some elements thegradients can be calculated correctly and in some can not and theboundary problem still exists. Is there any problemwith the above commands?Is there any specialmethod or library available for correctingthe wall elements boundary values? Can the problem stemfrom the mesh type? Regards,Soha