Remarks Concerning Duns and Isaac

If you intent to create a 2D-mesh for the cfd-code duns or isaac you have to watch out that all surfaces are created in the same order. That means that all surfaces must be defined clockwise or counter-clockwise. For isaac they have to be clockwise if you look in z direction. The block-structure can be detected only in this case. You can check the mesh by simply mesh it with linear shell-elements and display them. All elements must be either dark or illuminated. A later “qflp” or “flip” command will not cure wrong oriented surfaces since it only changes the “sign” in their definition and not the basic edge sequence, which is necessary here. The results of a calculation can be opened by specifying the parameter (-duns2d -duns3d -isaac2d -isaac3d) and the filenmae without any extention(cgx -isaac2d RAE2822). See also ”Program Parameters”, ”mesh”, ”send”. Watch also the airfoil-example in the distrib.