偏斜来流对圆柱跨声速绕流的影响  

Effects of Tilted Free-Stream on the Transonic Flow Past a Circular Cylinder

作　　者：许常悦[1] 孙智[1] 王从磊[1] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016

出　　处：《应用数学和力学》2014年第10期1135-1142,共8页Applied Mathematics and Mechanics

基　　金：国家自然科学基金(11202100);江苏省自然科学基金(BK2011723);江苏高校优势学科建设工程资助项目~~

摘　　要：采用大涡模拟方法数值研究了偏斜角为60°的偏斜圆柱跨声速绕流.基于非偏斜圆柱跨声速绕流的实验和数值研究工作,来流Mach数取为0.75,Reynolds数取为2×105.通过与相同参数的非偏斜圆柱跨声速绕流对比,分析了偏斜来流对柱体受力和流动特性的影响.由于偏斜来流的流动控制,偏斜圆柱的阻力比非偏斜圆柱的阻力减小高达45%,而振荡力仅受到较小的抑制.偏斜圆柱流场的可压缩性被弱化,激波和小激波消失,而整体流动的模态未改变.偏斜来流使得偏斜圆柱后的剪切层变得更为稳定,进而提升柱体背压.在剪切层的初始发展阶段,剪切层的扰动涡斜脱泻模态和快速动能衰减是偏斜圆柱剪切层更为稳定的两个主要原因.The transonic flow past a tilted cylinder at an angle of 60° was investigated numeri- caUy with the large eddy simulation technique. Based on the previous experimental results and computational researches on transonic flow past the non-tilted cylinder, the free-stream Mach number was chosen as 0.75 and Reynolds number as 2× 10^5. Compared with the transonic flow past a corresponding non-tilted cylinder, effects of the tilted free-stream on the force and flow characteristics of the tilted cylinder were analyzed. Because of flow control of the tilted free- stream, the mean drag coefficient of the tilted cylinder is less than that of the non-tilted cylin- der with a drag reduction up to 45%, while less suppression of the fluctuating force is obtained. Fluid compressibility in the tilted cylinder flow is weakened due to elimination of shocks and shocklets, however, no change occurs in the whole flow modes. Owing to the tilted free- stream, the shear layer shed from the tilted cylinder is more stable, which leads to a higher base-pressure distribution. Two main mechanisms are associated with the more stable shear lay- er behind the tilted cylinder, i.e., the oblique vortex-shedding mode and faster kinetic-energy damping in the initial stage of shear layer developement.

关 键 词：圆柱 偏斜圆柱 可压缩湍流 大涡模拟 流动控制 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程] O354.2[理学—流体力学]