VELOCITY-MEASUREMENTS IN 3D TURBULENT FLOWS BY MEANS OF A ROTATING X-WIRE PROBE

One of the problems encountered in 3D turbulent flow measurement when using a four-wire probe is that the equation system is overdetermined, bringing many sources of errors. In the present paper we discuss a method of resolution of such a problem by means of a rotating X-wire probe, and we define a well determined 6 x 6 matrix system in order to obtain the solution with a good accuracy. Comparisons with the normal single-wire and the rotating X-wire probe measurements show the validity of our method in the detached flow behind a 45 degrees swept backward-facing step. The advantage of the rotating X-wire probe is its good space resolution, giving a better accuracy in the 3D velocity and in the double-correlation determination.