Measurement of a round jet: Prediction of valvular regurgitation and its lesion size

The velocity profiles of an axisymmetric circular jet with initially laminar boundary layer condition were measured extensively from the jet exit to about 45 diameters (d) downstream with a single hot wire probe to verify a new quantification method for valvular regurgitation and its lesion size. The flow visualization using smoke-wire at the near field of the jet indicates that the interaction of the mixing layer is rather smooth and gentle. As a result, the self-preservation of the centerline local mean velocity (Uo) and half radius (Ru) were established at a rather short distance from the jet exit. The onset of self-preservation of Uo is found to be about 6d with initial laminar velocity condition and this distance may be used as a guide-line to predict the orifice of lesion (presumably circular in shape). Velocity measurements for valvular regurgitation jets for that for that matter, should be taken at a minimum distance of 6d.