), 郑静, 王哲, 王彬 南京航空航天大学 飞行器环境控制与生命保障工业和信息化部重点实验室, 南京 210016
收稿日期:2019-10-18出版日期:2021-04-28发布日期:2021-04-30作者简介:许常悦(1981-),男,河南省兰考县人,副教授,主要从事计算流体力学、飞行器环境与生命保障工程研究. 电话(Tel.):025-84896099;E-mail: 基金资助:国家自然科学基金(11572154);国家自然科学基金(11202100);江苏高校优势学科建设工程资助项目Shear Layer and Wake Characteristics of Square Cylinder in Transonic Flow
XU Changyue(), ZHENG Jing, WANG Zhe, WANG Bin Key Laboratory of Aircraft Environment Control and Life Support of the Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Received:2019-10-18Online:2021-04-28Published:2021-04-30摘要/Abstract
摘要： 采用尺度自适应模拟(SAS)方法研究了来流马赫数Ma为0.71、雷诺数Re为4×105的方柱跨声速绕流,并对分离剪切层和尾迹特性进行了深入分析.为了验证SAS方法的可靠性,将SAS结果与已有数值和实验结果进行了对比.在当前的跨声速流场中,剪切层中的对流马赫数约为0.6,这意味着Kelvin-Helmholtz不稳定性主导剪切层的初始阶段演化.在剪切层的初始阶段,可以看出扰动涡沿展向呈现滚筒状结构.剪切层外侧附近和方柱的回流区均出现倍频现象,这与剪切层中存在明显的涡合并有关.压力场的本征正交分解表明,方柱跨声速流场中的主导流动模态为反对称模态,这与尾迹中的涡脱落现象和剪切层引起的压缩波传播有关.
关键词: 方柱, 激波, 剪切层, Lamb矢量, 尺度自适应模拟
Abstract: The transonic flow around a square cylinder at Ma= 0.71 and Re= 4×105 has been studied by using the scale-adaptive simulation (SAS) method, and the characteristics of separated shear layer and wake have been analyzed in depth. To validate the SAS approach, the SAS results are compared with the existing numerical and experimental results. In the present transonic flow, the convective Mach number inside the shear layer is about 0.6. This indicates that the initial evolution of the separated shear layer is dominated by Kelvin-Helmholtz instability, and the roller spanwise eddies in the initial stage of the shear layer can be observed. In the regions near the shear layer and the wake, the doubling frequencies can be obtained indicative of the harmonic phenomenon inside the separated shear layer, which is closely related to the obvious merging of the vortices in the shear layer. Proper orthogonal decomposition of the pressure field shows that the transonic flow field of square cylinder is dominated by the antisymmetric mode, which is associated with the vortex shedding in the wake and the propagation of compression waves induced by the shear layer.
Key words: square cylinder, shock wave, shear layer, Lamb vector, scale-adaptive simulation
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