VELOCITY-GRADIENTS IN A TURBULENT JET FLOW

We present a selection of results from experiments on an air turbulent jet flow, which included measurements of all the three velocity compo nents and their nine gradients with the emphasis on the properties of invariant quantities related to velocity gradients (enstrophy, dissipa tion, enstrophy generation, etc.). This has been achieved by a 21 hot wire probe (5 arrays x 4 wires and a cold wire), appropriate calibrati on unit and a 3-D calibration procedure [1]. A more detailed account o n the results will be published elsewhere.