摘要: Simultaneous density-fluctuation measurements were made using a linear array focused laser differential interferometer (LA-FLDI) over a 7° sharp cone in Mach-6 flow. Second-mode fluctuations were measured and showed to vary in amp... 展开 Simultaneous density-fluctuation measurements were made using a linear array focused laser differential interferometer (LA-FLDI) over a 7° sharp cone in Mach-6 flow. Second-mode fluctuations were measured and showed to vary in amplitude with height above the surface and a Reynolds number sweep captured transition onset. As Reynolds number increased, the peak fluctuation height decreased due to the thinning of the boundary layer. The computed density eigenfunction was compared to the integrated FLDI measurements for one case. FLDI measurements were also compared to surface pressure fluctuation measurements made by a PCB sensor at the same axial position with excellent agreement. In particular, the second-mode peak frequency agreed within 10% between the two measurement techniques, and the second-mode amplitude peaked at the same freestream Reynolds for the most amplified FLDI height. 收起