A method was developed to measure reversed flow using a single slanted hot-wire probe.Probe rotating technique was used to measure three-dimensional velocities with a single-sensor probe

and the wake of the prong was used to determine the direction of the flow.The method was applied to measure the rotating stall in a low speed axial compressor.The results give a detail view of the flow structure in the rotating stall cell

demonstrating that this technique is simple and accurate in the measurement of reversed flow.It is especially applicable in the measurement of three dimensional flow field within turbomachinery.