Influence of Environmental Disturbances on Hypersonic Crossflow Instability on the HIFiRE-5 Elliptic Cone

Abstract

Crossflow instabilities on a 2:1 elliptic cone in hypersonic flow have been investigated in the M6QT and ACE wind tunnels at the Texas A&M National Aerothermochemistry and Hypersonics Laboratory. Experiments on a PEEK 38.1% scale model of the HIFiRE-5 flight test geometry were conducted to investigate the development of crossflow instabilities as well as to characterize the freestream and surface conditions responsible for their initial amplitudes. The freestream environment was varied not only by testing the model in both quiet and conventional tunnels but also by passively changing the fluctuation levels experienced in the conventional facility through systematic model placement. ACE freestream measurements, using a Kulite pressure transducer mounted in a pitot probe configuration and a hot-wire anemometer, indicated that fluctuation levels at the upstream model station were half those at the downstream stations. Fast-response PCB and Kulite surface mounted pressure transducers allowed examination of pressure fluctuation amplitudes and

Preflight Ground Test Analyses of the Boundary Layer Transition (BOLT) Flight Geometry

“…Early transition and stability work involved 2-D planar and axisymmetric shapes with insight on the first-and second-mode instability mechanisms by Mack, Fedorov, and Zhong and Wang [2][3][4]. Geometries featuring a 3-D boundary layer gave way to a greater understanding of traveling and stationary crossflow, first and second modes, and even secondary instabilities [5][6][7][8][9][10]. The Hypersonic International Flight Research Experimentation (HIFiRE) program was developed to further understand boundary-layer transition for development of technology critical for the advancement in hypersonics.…”

“…The Hypersonic International Flight Research Experimentation (HIFiRE) program was developed to further understand boundary-layer transition for development of technology critical for the advancement in hypersonics. Many ground tests and simulations have been made with a 38.1% scale HIFiRE-5 model before and after the flight test [9][10][11][12][13][14][15]. Natural crossflow transition was observed on the surface of the elliptic cone during quiet-tunnel experiments.…”

“…Although it is predicted to have higher growth rates, traveling crossflow is not observed to be the dominant mechanism in a low-disturbance environment. Experimental studies by Neel et al examined freestream disturbance effects on the transition process on a 38.1% scale HIFiRE-5 model by comparing results in the Texas A&M University (TAMU) Mach 6 Quiet Tunnel (M6QT) and Actively Controlled Expansion (ACE) tunnel [9,10]. Within the two freestream environments, the transition process on the elliptic cone was qualitatively and quantitatively different.…”

“…The ACE tunnel is a variable-Mach-number conventional facility and has previously been modified for studies on the BOLT geometry [26]. The M6QT contains a polished nozzle with an exit diameter of 0.19 m. The installation of the BOLT model within ACE and the M6QT is similar to the procedure described by Neel et al for the HIFiRE-5 model [10]. However, the purely aluminum TAMU model is present during preheat in the M6QT.…”

Wall pressure beneath a transitional hypersonic boundary layer over an inclined straight circular cone

“…[1][2][3]), especially in hypersonic conditions. Therefore, in the last decades, considerable efforts have been made towards building a fundamental understanding to the transition of hypersonic three-dimensional boundary layers by wind tunnel experiments [4][5][6][7][8][9], theoretical analyses [10][11][12][13], direct numerical simulations (Chen et al: Transition of hypersonic boundary layer over a yawed blunt cone, submitted) (Chen et al: Stationary cross-flow breakdown in a high-speed swept-wing boundary layer, submitted) and flight tests (see overview [14]). Nevertheless, much is still unknown.…”