A method for measuring recompression shock unsteadiness applied to two supersonic wakes

摘要

The recompression shock system in blunt-base cylinder wakes at 0 degrees and 10 degrees angles-of-attack to an M = 2.46 freestream is visualized by planar laser scattering, allowing the instantaneous position of the shock to be determined over a wide region of the flow. The recompression shock at alpha = 0 degrees is highly branched and appears to be quite weak. The shock appears to be stronger at alpha = 10 degrees, with far less branching. Correlation analysis for the alpha = 10 degrees wake indicates that fluctuations in the shock position tend to be correlated over relatively long streamwise distances. Analysis of the shock angle for the angle-of-attack wake shows a significant variation in the local angle of the shock, with trends similar to those seen for the unsteadiness in the shock position.