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.