ASA 124th Meeting New Orleans 1992 October

2pPA8. Results from a sonic boom signature distortion algorithm combined with a turbulent boundary layer evolution model.

Thomas A. Gionfriddo

Victor W. Sparrow

Graduate Prog. in Acoust., Penn State Univ., 157 Hammond Bldg., University Park, PA 16802

Recently a new algorithm for quantifying the distortion of sonic boom signatures was presented by Gionfriddo [J. Acoust. Soc. Am. 91, 2453 (A) (1992)]. In that study digitized sonic boom waveforms from aircraft overflights recorded by the Air Force were compared to classic N waves. A statistical relation between the waveform distortion and the amount of turbulence a sonic boom encounters during propagation was sought. That study assumed a turbulent boundary layer of constant height. In the present research the height of the turbulent boundary layer has been allowed to change based on use of the Blackadar (1989) model. In this model meteorological data from rawinsonde, satellite, and ground station sources during the days of the overflights provide a more accurate estimate of the boundary layer size. It has been observed that in some cases, there exists a strong linear correlation between the sonic boom signature distortion and the amount of turbulence through which the wave traveled. In the remaining cases, a good to fair level of correlation is reported. [Work supported by NASA---LaRC.]