15 - 2   Surface Streamtraces on No-slip Boundaries

A no-slip boundary is the boundary of a volume zone whose vector variables are either passive or are zero throughout the boundary. The boundary may be either a displayed boundary of a volume zone (included in the zone's Surfaces to Plot setting in the Zone Style dialog), or a surface zone that resides on the boundary of a volume zone. In the latter case, the surface zone's nodes must coincide with nodes on the exterior of one or more volume zones. For either case, blanked regions of the surface are not considered when determining whether a boundary is a no-slip boundary. That is, if value blanking or IJK blanking is enabled, then only the non-blanked portion of the surface is examined to determine if it is a no-slip boundary.

When surface streamtraces are placed on a no-slip boundary, they propagate according to the normal gradient of tangential velocity (proportional to shear stress) at the surface, calculated using vector variable values from the nearby interior of the volume zone. If the solution is unsteady, only volume zones in the currently displayed solution time will be used. If the boundary is a surface zone, then corresponding volume zones needn't be displayed in the current plot (they may be turned off in the Zone Style dialog), but preference will be given to volume zones that have non-zero velocity, and that are active (not turned off in the Zone Style dialog).