THE PERTURBATION FLOW FIELD ASSOCIATED WITH PASSAGE OF TURBULENT SPOT (RESEARCH NOTE)

(The flow field associated with the passage of the turbulent spot in a 3–D duct with streamline divergence under zero pressure gradients was investigated and displayed as contour plots of the velocity perturbation in plan and elevation view of the spot. It suggests that, streamline divergence has no strong effect on the internal structure of the spot and eddies and their propagation in the downstream direction is similar to 2–D flows. The orthographic views are also shown. They are rather similar to contour plots but with different kind of presentation to show velocity excess and deficit as peaks and valleys respectively in the flow field while passage of the spot. This work was a part of detailed investigation of the structure of a distorted turbulent spot in a 3–D constant pressure flow