Superimposed Wall Jet Velocity and Vorticity Fields
The velocity field is superimposed on the vorticity field as shown below.
It can be clearly seen that the fluid is entrained from the ambient into the
vortices. Also, as the upper vortices approach the surface, there is an upward
ejection of the fluid from the wall. The wall jet flow is highly unstable as
compared to a typical boundary layer. This strong flow-surface interaction is
important in practical applications such as the film cooling consideration of flow over
trubine blades of a jet engine.