The suppression of flow separation by sequential wall jets

The performance of many fluid flow devices is limited by the separation of the turbulent boundary layer. This separation may be suppressed or delayed by use of wall jets, raising questions of jet location and strength. A numerical analysis of a single wall jet gave results in close agreement with experiment. The same calculation procedure indicated that two sequential wall jets, with the same total kinetic energy flux as the single jet, would suppress separation under conditions where the single jet would not. The best two-jet arrangement would be achieved with 63 percent of the total kinetic energy flux in the first jet. It is possible that three-jet arrangements could provide some further improvement.