Experimental study on shock wave modulation caused by velocity and temperature fluctuations in-cylinder wake

K. Inokuma,T. Watanabe, K. Nagata, Y. Sakai
Experimental study on shock wave modulation caused by velocity and temperature fluctuations in-cylinder wake
Physical Review Fluids, 6 063401 2021

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This article may be found at https://doi.org/10.1103/PhysRevFluids.6.063401.

Abstract

Experiments on a spherical shock wave propagating across an unheated- or a heated-cylinder wake are performed in a wind tunnel to investigate the effects of velocity and temperature fluctuations of turbulence on the shock wave. The temperature of the heated cylinder is low enough for the buoyancy effect to be negligible in the wake development, and comparisons between the heated- and unheated-cylinder experiments highlight the effects of temperature fluctuations on the shock wave. Peak overpressure of the spherical shock wave is measured on a wall after the shock wave has passed the wake. Along with the overpressure measurement, temperature and velocity are measured in the heated and unheated wakes, respectively. Larger peak-overpressure fluctuations are obtained when the shock wave interacts with the heated-cylinder wake than with the unheated-cylinder wake. Correlation coefficients are calculated between the velocity/temperature fluctuations of the unheated/heated-cylinder wakes and peak-overpressure fluctuations. The temperature fluctuations and overpressure fluctuations are found to be negatively correlated, which is explained by the shock deformation caused by speed-of-sound fluctuations in front of the shock wave. By comparing the correlation coefficients between velocity and overpressure fluctuations with those between temperature and overpressure fluctuations, it is also discovered that the temperature fluctuations of the heated-cylinder wake have a stronger correlation with the overpressure fluctuations than the velocity fluctuations of the unheated-cylinder wake.

日本語訳 (DeepL翻訳)

円柱後流の速度・温度変動による衝撃波変調の実験的研究

非加熱円柱または加熱円柱後流を伝播する球形衝撃波の風洞実験を行い、衝撃波に及ぼす乱流の速度変動と温度変動の影響を調べた。加熱円柱の温度は後流の発達において浮力効果が無視できるほど低く、加熱円柱と非加熱円柱の実験の比較により、衝撃波に対する温度変動の影響が浮き彫りになった。球形衝撃波のピーク圧力は、衝撃波が後流を通過した後、壁面で測定されます。圧力測定と同時に、加熱された後流と非加熱の後流の温度と速度もそれぞれ測定します。衝撃波が加熱された後流と相互作用した場合、加熱されていない後流と比較して、より大きなピーク圧力変動が得られます。非加熱/加熱円柱後流の速度/温度変動とピーク圧力変動との相関係数を計算したところ、温度変動とピーク圧力変動は、非加熱円柱後流の方が加熱円柱後流よりも大きいことがわかった。温度変動と過圧変動は負の相関があることがわかり、これは衝撃波の前の音速変動による衝撃変形によって説明される。また、速度変動と過圧変動の相関係数と温度変動と過圧変動の相関係数を比較した結果、加熱円柱後流の温度変動は非加熱円柱後流の速度変動よりも過圧変動に強い相関があることがわかった。

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