A FAST SIMPLE HOT-WIRE METHOD OF DETERMINING THE MEAN VELOCITY VECTOROF COMPLEX 3-DIMENSIONAL FLOWS

A fast and simple method of determining the mean velocity vector of co mplex three-dimensional flow fields is outlined. Straight and slanted single hot-wires are rotated in two perpendicular planes. This method increases the angular resolution, which is of importance in flow situa tions where one of the velocity components dominates and the other cha nges rapidly from one point to another. The method was calibrated in a wind tunnel and assessed in the internal flow field at the outlet of a fan in a defroster channel. It is shown that the hot-wire method yie lds good agreement with corresponding flow visualizations determined u sing a textile thread, and an integration of the measured mean flow yi elds a flow rate which agrees within a few percent with corresponding direct measurements on an orifice plate.