Dual Probe Digital Sampling (DPDS) Technique for Rotor Flows--Review of the Development and an Assessment Based on Early Results.

The state of the art in the development of the DPDS technique at the Turbopropulsion Laboratory at the Naval Postgraduate School is reported. In principle, this method allows the determination of three dimensional flow fields behind rotors. A review of the instrumentation and hardware is given and two different data reduction procedures developed earlier are described. The results of reducing one set of rotor exit data using the two methods are compared. In order to verify the experimental procedures at low cost, a bench-top periodic flow generator was used first to provide signals similar in type and frequency to those from the Transonic Compressor in which the rotor exit flow was measured. The data measured in the compressor were analyzed, and problems encountered in the routine application of the reduction methods were identified. The possible application of similar techniques in the Rotating Annular Cascade RGG at the DFVLR Gottingen is assessed and recommendations are made for the coordination of future experimental programs. Author