Relationship between wall shear stresses and streamwise vortices

• Published in: Applied mathematics and mechanics Vol. 40; no. 3; pp. 381 - 396
• Main Authors: Wang, Lihao, Huang, Weixi, Xu, Chunxiao, Shen, Lian, Zhang, Zhaoshun
• Format: Journal Article
• Language: English
• Published: Shanghai Shanghai University 01.03.2019; Springer Nature B.V
• Edition: English ed.
• Subjects: Applications of Mathematics; Classical Mechanics; Computational fluid dynamics; Computer simulation; Correlation coefficients; Direct numerical simulation; Fluid- and Aerodynamics; Mathematical Modeling and Industrial Mathematics; Mathematics; Mathematics and Statistics; Partial Differential Equations; Shear stress; Vertical distribution; Vortices; Vorticity; Wall shear stresses; Waves; direct numerical simulation (DNS); near-wall streamwise vortex; 76F40; O357.5; two-point correlation; wall shear stress
• ISSN: 0253-4827; 1573-2754
• DOI: 10.1007/s10483-019-2448-8

The relationship between wall shear stresses and near-wall streamwise vortices is investigated via a direct numerical simulation (DNS) of turbulent flows over a wavy boundary with traveling-wave motion. The results indicate that the wall shear stresses are still closely related to the near-wall streamwise vortices in the presence of a wave. The wave age and wave phase significantly affect the distribution of a two-point correlation coefficient between the wall shear stresses and streamwise vorticity. For the slow wave case of c / U m = 0.14, the correlation is attenuated above the leeward side while the distribution of correlation function is more elongated and also exhibits a larger vertical extent above the crest. With respect to the fast wave case of c / U m = 1.4, the distribution of the correlation function is recovered in a manner similar to that in the flat-wall case. In this case, the maximum correlation coefficient exhibits only slight differences at different wave phases while the vertical distribution of the correlation function depends on the wave phase.