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Scaling for compression waves/boundary layer interaction based on equivalent interaction intensity

Published online by Cambridge University Press:  07 January 2026

Nan Li
Affiliation:
School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, PR China National Key Laboratory of Aircraft Configuration Design, Xi’an 710072, PR China International Joint Institute of Artificial Intelligence on Fluid Mechanics, Northwestern Polytechnical University, Xi’an 710072, PR China
Xuanfei Yu*
Affiliation:
National Key Laboratory of Solid Rocket Propulsion, Northwestern Polytechnical University, Xi’an 710072, PR China
Zhengyin Ye
Affiliation:
School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, PR China National Key Laboratory of Aircraft Configuration Design, Xi’an 710072, PR China International Joint Institute of Artificial Intelligence on Fluid Mechanics, Northwestern Polytechnical University, Xi’an 710072, PR China
Weiwei Zhang
Affiliation:
School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, PR China National Key Laboratory of Aircraft Configuration Design, Xi’an 710072, PR China International Joint Institute of Artificial Intelligence on Fluid Mechanics, Northwestern Polytechnical University, Xi’an 710072, PR China
*
Corresponding author: Xuanfei Yu, yuxuanfei@nwpu.edu.cn

Abstract

The compression waves/boundary layer interaction (CWsBLI) in high-speed inlets poses significant challenges for predicting flow separation, rendering traditional shock wave/boundary layer interaction (SWBLI) scaling laws inadequate due to unaccounted effects of the coverage range of compression waves. This study aims to establish a unified scaling framework for CWsBLIs and SWBLIs by proposing an equivalent interaction intensity. Experiments were conducted in a Mach 2.5 supersonic wind tunnel, employing schlieren imaging and pressure measurements to characterise flows induced by curved surfaces at two deflection angles ($10^{\circ }, 12^{\circ }$) and varying coverage ranges of compression waves ($d$). An equivalent transformation method was developed to convert the CWsBLI into an equivalent incident SWBLI (ISWBLI), with interaction intensity derived from pressure gradients considering the coverage range. Key results reveal a critical threshold based on the interaction length of ISWBLI ($L_{\textit{single}}$): when $d \leq L_{\textit{single}}$, the interaction scale remains comparable to ISWBLI; when $d \gt L_{\textit{single}}$, the weakened adverse pressure gradient leads to a reduction in the length scale. The proposed scaling framework unifies the CWsBLIs and SWBLIs, achieving better data collapse compared to the existing methods. This work advances our understanding of complex waves/boundary layer interactions, and provides a prediction method for the length scales of CWsBLIs.

Information

Type
JFM Papers
Copyright
© The Author(s), 2026. Published by Cambridge University Press

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