马赫数为4的压缩坡道上流向涡的参数分析

IF 1.8 4区工程技术 Q3 MECHANICS

Shock Waves Pub Date : 2025-06-17 DOI:10.1007/s00193-025-01239-z

K. Dixit, R. R. Kumar, N. R. Vadlamani, N. Tsuboi

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引用次数: 0

摘要

在自由流马赫数为4.0、单位雷诺数为\(4.56 \times 10^{6}\) / m时，对压缩坡道上的超声速流动进行了大涡模拟。考虑了两个斜坡角\(15^\circ \)和\(18^\circ \)以及三个不同的斜坡位置（P1， P2和P3），从板前缘，板的长度逐渐增加，从P1到P3。仿真结果表明，随着平板长度和斜坡角的增大，分离点向下游移动，分离长度也随之延长。此外，随着斜坡角和钢板长度的增加，在再附着的上游观察到更高的Görtler数，表明更有可能发生Görtler不稳定。特别是在15P1和15P2中没有观测到流向涡，而在18P3中，不稳定性的增加导致了流向涡的破坏，推动了向湍流的过渡。从18P1到18P3，随着板长增加\(\approx 80\%\)，流向条纹的波长大约减少\(15\%\)。非定常分析揭示了这些涡旋上沿展向的次级不稳定性的作用，它触发了以\(\approx 0.6 U_{\infty }\)速度传播的湍流点。斯坦顿数的峰值为\(\approx \) 15-27% higher than the time and span-averaged value for the 15P3 and 18P3 cases, highlighting a strong effect of downwash due to streamwise vortices on the wall heating rate distribution. The unsteady data also reveal a negative correlation between the flow reattachment location and the Stanton number close to the reattachment point. An earlier reattachment is shown to increase the Stanton number and vice versa resulting in a \(\approx 40\%\) variation compared to the time-averaged value. The results from this study underscore the critical influence of plate length on the formation of streamwise vortices, with significant implications for wall heating rate distribution and flow transition dynamics.

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A parametric analysis of streamwise vortices on a compression ramp at Mach 4

Large-eddy simulations are conducted to investigate supersonic flow over a compression ramp at a free stream Mach number of 4.0 and a unit Reynolds number of \(4.56 \times 10^{6}\) per meter. Two ramp angles of \(15^\circ \) and \(18^\circ \) are considered along with three different ramp positions (P1, P2, and P3) from the plate leading edge, with the plate length increasing progressively from P1 to P3. Simulations reveal that with an increase in the plate length and ramp angle, the separation point shifts downstream, accompanied by an extended separation length. Furthermore, with an increase in the ramp angle and plate length, a higher Görtler number is observed upstream of the reattachment indicating a greater likelihood of Görtler instability. In particular, no streamwise vortices were observed for the 15P1 and 15P2 cases, while for the 18P3 case, increased instability resulted in the breakdown of streamwise vortices, driving the transition to turbulence. The wavelength of streamwise streaks decreased by approximately \(15\%\) as the plate length increased by \(\approx 80\%\) from 18P1 to 18P3. Unsteady analysis revealed the role of spanwise secondary instabilities over these vortices, that trigger turbulent spots that propagate at a speed of \(\approx 0.6 U_{\infty }\). The peak value of the Stanton number is found to be \(\approx \) 15–27% higher than the time and span-averaged value for the 15P3 and 18P3 cases, highlighting a strong effect of downwash due to streamwise vortices on the wall heating rate distribution. The unsteady data also reveal a negative correlation between the flow reattachment location and the Stanton number close to the reattachment point. An earlier reattachment is shown to increase the Stanton number and vice versa resulting in a \(\approx 40\%\) variation compared to the time-averaged value. The results from this study underscore the critical influence of plate length on the formation of streamwise vortices, with significant implications for wall heating rate distribution and flow transition dynamics.

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来源期刊

Shock Waves 物理-力学

CiteScore

4.10

自引率

9.10%

发文量

审稿时长

17.4 months

期刊介绍： Shock Waves provides a forum for presenting and discussing new results in all fields where shock and detonation phenomena play a role. The journal addresses physicists, engineers and applied mathematicians working on theoretical, experimental or numerical issues, including diagnostics and flow visualization. The research fields considered include, but are not limited to, aero- and gas dynamics, acoustics, physical chemistry, condensed matter and plasmas, with applications encompassing materials sciences, space sciences, geosciences, life sciences and medicine. Of particular interest are contributions which provide insights into fundamental aspects of the techniques that are relevant to more than one specific research community. The journal publishes scholarly research papers, invited review articles and short notes, as well as comments on papers already published in this journal. Occasionally concise meeting reports of interest to the Shock Waves community are published.