Wall shear-stress extraction by an optical flow algorithm with a sub-grid formulation

作     者：The Hung Tran Lin Chen The Hung Tran;Lin Chen

作者机构：Faculty of Aerospace EngineeringLe Quy Don Technical UniversityHanoi10000Vietnam Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing100190China School of Aeronautics and AstronauticsUniversity of Chinese Academy of SciencesBeijing100049China 

出 版 物：《Acta Mechanica Sinica》 (力学学报（英文版）)

年 卷 期：2021年第37卷第1期

页      面：65-79,I0003页

核心收录：

学科分类：08[工学] 080103[工学-流体力学] 0802[工学-机械工程] 0701[理学-数学] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Department of Aerospace Engineering, Tohoku University Department of Mechanical and Aerospace Engineering, Western Michigan University Trường Đại học Duy Tân, DTU 

主　　题：Wall shear-stress Optical flow Thin-oil-film equation Sub-grid model 

摘      要：In this study,we developed a novel optical-flow algorithm for determining the wall shear-stress on the surface of objects.The algorithm solves the thin-oil-film equation using a numerical scheme that recovers local features neglected by smoothing filters.A variational formulation with a smoothness constraint was applied to extract the global shear-stress fields.The algorithm was then applied to scalar images generated using direct numerical simulation(DNS)method,which revealed that the errors were smaller than those of conventional methods.The application of the proposed algorithm to recover the wall shear-stress on a low-aspect-ratio wing and on an axisymmetric boattail model taken as examples in this study showed a strong potential for analysing shear-stress fields.Compared to the methods used in previous studies,proposed method reveals more local features of separation line and singular points on object surface.