Two-point statistics of coherent structures in turbulent flow over riblet-mounted surfaces  

作　　者：Weipeng Li Hong Liu 

机构地区：[1]School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Acta Mechanica Sinica》2019年第3期457-471,共15页力学学报（英文版）

基　　金：the National Basic Research Program of China (973 program)(Grants 2014CB744802 and 2014CB744804);the National Natural Science Foundation of China (Grants 11772194 and 91441205).

摘　　要：Direct numerical simulations (DNS) of turbulent flow over a drag-reducing and a drag-increasing riblet configuration are performed. Three-dimensional two-point statistics are presented for the first time to quantify the interaction of the riblet surfaces with the coherent, energy-bearing eddy structures in the near-wall region. Results provide statistical evidence that the averaged organization of the streamwise vortices in the drag-reducing case is lifted above the riblet tip, while in the drag-increasing case the streamwise vortices are embedded further into the riblet cove. In the spanwise direction, the cores of the streamwise vortices over the riblet surfaces are shown to be closer to each other than those for flow over the smooth wall, and wider riblet spacing leads to more reduction on their spanwise distances. In the cases with riblets the streamwise vortices have longer streamwise lengths, but their inclination angles do not change much.

关 键 词：TURBULENT drag reduction RIBLETS Coherent structures 

分 类 号：O3[理学—力学]