EXPERIMENTAL INVESTIGATION OF THE EFFECT OF NOZZLE SHAPE AND TEST SECTION PERFORATION ON THE STATIONARY AND NON-STATIONARY CHARACTERISTICS OF FLOW FIELD IN THE LARGE TRANSONIC TSAGI T-128 WIND TUNNEL

摘要

The results are presented for a cycle of experimental investigations of flow field characteristics (static pressure distribution, static pressure fluctuations, upwash, boundary layer parameters) in the perfo- rated test section of the transonic TsAGI T-128 wind tunnel. The investigations concern the effect of noz- zle shape, wall open-area ratio, Mach and Reynolds numbers on the above-outlined flow characteristics. During the tests, the main wind tunnel drive power is measured. Optimal parameters of the nozzle shape and test section perforation are obtained to minimize acoustic perturbations in the test section and their non-uniformity in frequency, static pressure field non-uniformity, nozzle and test section drag and, accordingly, required main wind tunnel drive power.