Improvement of the free-interaction theory for shock wave/turbulent boundary layer interactions

Xie, Wen-zhong; Yang, Shu-Zi; Zeng, Cheng; Liao, Kai; Ding, Run-Han; Zhang, Lu; Guo, Shengmin

doi:10.1063/5.0050113

Cited by 20 publications

(6 citation statements)

References 62 publications

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“…2020; Xie et al. 2021), etc., can also affect the separation feature of SWBLIs. However, when creating a theoretical model to predict the pressure plateau of separation, it is very difficult to consider all the effects, and only the main factors might be utilized for the equation.…”

Section: Introductionmentioning

confidence: 99%

Pressure plateau of separation induced by shock impingement in a Mach 5 flow

Xue,

Jiao,

Wang

et al. 2023

J. Fluid Mech.

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Separation induced by impinging shock is a fundamental feature in supersonic and hypersonic flows; however, it is difficult to predict the pressure plateau due to a limited theoretical understanding of the effect of impinging shock strength. In this study, the evolution of the separation configuration and pressure distribution with changes in impinging shock angle is examined, and a theoretical equation for predicting the pressure plateau based on minimum entropy production is proposed. For validation, an experimental device that can measure wall pressure in the separation region at high spatiotemporal resolution is developed, and schlieren visualization is employed to capture the flow structure. Accordingly, the fine characteristics of pressure distributions along the centreline of the separation region as well as the reattachment region induced by shock impingement at various angles ( $8.5^\circ$ to $30.5^\circ$ ) are obtained in a flow of Mach number 5 and Reynolds number ${\approx }1.4\times 10^7\ {\rm m}^{-1}$ . The experimental results agree well with the theoretical results; both indicate that the pressure distribution is strongly related to the impinging shock strength and that there is a critical flow deflection angle $\alpha ^\ast$ ( ${\approx }20.8^\circ$ for Mach 5). The pressure in the separation region grows nearly linearly with increasing impinging shock strength when the flow deflection angle of the impinging shock is less than $\alpha ^\ast$ ; the pressure stops growing and resides in a small range when the flow deflection angle is larger than $\alpha ^\ast$ . Therefore, the impinging shock strength should be considered a main factor when predicting the pressure plateau.

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Section: Introductionmentioning

confidence: 99%

Pressure plateau of separation induced by shock impingement in a Mach 5 flow

Xue,

Jiao,

Wang

et al. 2023

J. Fluid Mech.

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“…3,[12][13][14] An important aspect of such a flowfield is the unsteadiness induced by the interaction, [15][16][17][18][19] which can either be local or global, as in the case of self-sustained oscillatory flows. [20][21][22][23] The effects of local unsteadiness on the flowfield are minimal and can be mitigated using control techniques. However, the global unsteadiness specifically induced by the geometrical configuration significantly modifies the overall flowfield.…”

Section: Introductionmentioning

confidence: 99%

Unsteady pulsating flowfield over spiked axisymmetric forebody at hypersonic flows

et al. 2022

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The paper gives experimental observations of the hypersonic flow past an axisymmetric flat-face cylinder with a protruding sharp-tip spike. Unsteady pressure measurements and high-speed schlieren images are performed in tandem on a hypersonic Ludwieg tunnel at a freestream Mach number of M 1 ¼ 8:16 at two different freestream Reynolds numbers based on the base body diameter (Re D ¼ 0:76 Â 10 6 and 3:05 Â 10 6 ). The obtained high-speed images are subjected further to modal analysis to understand the flow dynamics parallel to the unsteady pressure measurements. The protruding spike of length to base body diameter ratio of ½l=D ¼ 1 creates a familiar form of an unsteady flowfield called "pulsation." Pressure loading and fluctuation intensity at two different Re D cases are calculated. A maximum drop of 98.24% in the pressure loading and fluctuation intensity is observed between the high and low Re D cases. Due to the low-density field at low Re D case, almost all image analyses are done with the high Re D case. Based on the analysis, a difference in the pulsation characteristics is noticed, which arises from two vortical zones, each from a system of two "k" shocks formed during the "collapse" phase ahead of the base body. The interaction of shedding vortices from the k-shocks' triple-points, along with the rotating stationary waves, contributes to the asymmetric high-pressure loading and the observation of shock pulsation on the flat-face cylinder. The vortical interactions forming the second dominant spatial mode with a temporal mode carry a dimensionless frequency (f 2 D=u 1 % 0:34) almost twice that of the fundamental frequency (f 1 D=u 1 % 0:17). The observed frequencies are invariant irrespective of the Re D cases. However, for the high-frequency range, the spectral pressure decay is observed to follow an inverse and À7/3 law for the low and high Re D cases, respectively.

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“…Most early work on the interaction of shock waves with turbulence have been limited to calorically perfect gases in boundary layers [21][22][23][24][25][26][27][28][29][30] , and isotropic free streams [31][32][33][34][35] . Large-scale numerical simulations, including DNS [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] , LES [51][52][53] , and RANS 54,55 , have been the pacing item for those investigations.…”

Section: Introductionmentioning

confidence: 99%