Effect of surface roughness element on near wall turbulence with zero-pressure gradient

作     者：ZHANG Xin PAN Chong SHEN JunQi WANG JinJun 

作者机构：School of AeronauticNorthwestern Polytechnical University Fluid Mechanics Key Laboratory of Ministry of EducationBeijing University of Aeronautics and Astronautics 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2015年第58卷第6期

页      面：95-102页

核心收录：

学科分类：080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by National Natural Science Foundation of China(Grant Nos.11490552 and 11372001) 

主　　题：turbulent coherent structures low-speed streak flow control 

摘      要：In the present paper,we present an investigation on the effect of roughness elements onto near-wall kinematics of a zeropressure-gradient turbulent boundary *** array of spanwisely-aligned cylindrical roughness elements was attached to the wall surface to regulate the near-wall low-speed streaky *** both qualitative visualization and quantitative measurement,we found that the regularization only occurs in the region below the height of the roughness *** analysis on the probability distribution of the streak spanwise spacing showed that the mean spanwise streak spacing is dominated by the roughness elements;however,the latter s effect is in competition with the intrinsic streak generation mechanisms of smooth wall *** the top of the roughness elements,local streamwise turbulent fluctuation intensity can be reduced by about 10%.We used POD analysis to depict such regularization effect in terms of near-wall structure *** further found that if the spanwise spacing of roughness elements increased to be larger than the mean streak spacing in the smooth wall turbulence,there is no streak-regularization effect in the buffer region,so that the near-wall streamwise turbulent fluctuation intensity doesn t reduce.