| 摘要: |
| 采用卨精度紧致型差分格式求解三维可压缩Navier-Stokes方程,通过在局部平板上引人周期性吹吸气小扰动 的方法，ft接数值模拟来流马赫数为2. 25的空间发展的可压缩平板湍流边界层。所得流场统计特征与相关理 论和试验符介较好。在此基础上研究可压缩效应对平均流动特征以及湍能的生成和耗散特征的影响，指出在= 2.25的情况下，Morkovin假设基本成立，但可压缩效应使得拟序结构有明显差别。与不可压相比上抛、下扫对不同 区域的作用有所不同。在近壁区,压力-膨胀项和压力_速度相关项仍是不可忽略的量，这导致声的产生和可压缩效 应对湍能产生抑制作用。平板上声压的分布表明,随流动向下游的发展,边界层转捩过程激发了由物面脉动压力所 产牛的偶极子声源。 |
| 关键词: 可《缩效应 平板湍流边界层 直接数值模拟 湍能 |
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| Direct numerical simulation of compressible effects on flat-plate turbulent boundary layer |
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GAO Hui
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(College of Petroleum Engineering in China University of Petroleum，Qingdao 266555 , China)
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| Abstract: |
| A direct numerical simulation of a spatially evolving compressible flat-plate turbulent boundary layer with incoming Mach number Mx for 2. 25 was performed for solving three-dimensional compressible Navier-Stokes equations using high order compact finite difference schemes, through introducing a periodic blowing and suction disturbance on the upstream local wall. The turbulent statistics results agree well with the related theoretical and experimental data. The compressible effects on the characteristics of mean flow and production and dissipation of turbulent energy in flat-plate turbulent boundary layer flow were analyzed，and Morkovin's hypothesis comes into existence basically under the condition of MK for 2. 25. However, the results show that the ordered structures are different obviously on the effect of the compressibility. The action on different region for up-throwing and down-sweeping in the compressible turbulent boundary layer flow is different from that in the incompressible channel turbulent flow. The terms of pressure-dilatation and pressure-velocity can not be neglected near the wall, which leads to the production of sound and the restrained action to turbulent energy produced by compressibility effects. Further ,the situation of the sound pressure on the wall of the compressible flat-plate turbulence was presented, which shows that the source of noise produced by the pulsation pressure was inspired during the transitional progress with the evolving of the boundary layer flow. |
| Key words: compressible effect flat-plate turbulent boundary layer direct numerical simulation turbulent energy |
