Wall Pressure Fluctuations of Low-Supersonic Expansion-Corner Flow

超音速擴張角流表面壓力擾動特性探討

鍾光民(Guang-Ming Chung)

《中國航空太空學會學刊》 30卷3期 (1998/09) Pp. 231-236

https://doi.org/10.6124/TAASRC.199809_30(3).08

摘要

本研究旨在探討擴張角流對超音速紊流邊界層之影響，由表面壓力分佈顯示，在M=1.28時，擴張扇影響之範圍並未如較高音速時隨擴張角度而增加，此流場基本上可視爲一非黏滯流，而表面壓力擾動衰減量則隨擴張角度增加更顯著，同時由自相關函數及頻譜分析顯示擴張角流造成紊邊界層渦流結構之改變（包括高頻能量之衰減及壓力渦流之膨脹）。在擴張角下游3至5倍邊界層厚度，紊流邊界層回復－新的穩定狀態。

關鍵字

紊流邊界層 ； 擴張扇

並列摘要

Experiments were performed to study the viscous-inviscid interaction between a turbulent boundary layer and an expansion comer. Mean and fluctuating surface pressure of a Mach 1.28 turbulent flow past expansion comers were obtained. Mean surface pressure distributions showed small interaction region. This indicated that flows can be approximately treated as inviscid. Intensities of pressure fluctuation decreased downstream of the comers and tended to reach some equilibrium levels within three to five incoming boundary layer thickness. In addition, the microscales of pressure eddies increased and high-frequency components of power spectra damped. This indicated the dilatation of turbulent boundary layer and diminishing of inner layer oscillation with presence of the expansion comer. The boundary layer was developed to a new equilibrium state within a few boundary layer thickness.

並列關鍵字

turbulent boundary layer ； expansion comer