Vortex Structure Analysis of Grooved Surface Flow Loss

4th International Conference on Energy Equipment Science and Engineering

Liu, Mei^1^2 ; Li, Shuguang^1 ; Zhang, Kaishun^1 ; Yang, Hongyue^1 ; Wang, Songling^1

School of Energy, Power and Mechanical Engineering, North China Electric Power University, Baoding, Hebei

071003, China^1

Department of Economic Management, North China Electric Power University, Baoding, Hebei

071003, China^2

关键词: Coherent structure;    Hairpin vortices;    Internal velocity;    Near-wall region;    Rotational motion;    Velocity gradients;    Viscous resistance;    Vortex structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/242/6/062035/pdf
DOI  :  10.1088/1755-1315/242/6/062035

来源: IOP

【 摘 要 】

Large eddy simulations were used to study the effect of groove structures on rotational motion of fluid in wall turbulence, from the perspective of coherent structures. The results show that groove structures reduce the per unit normal height internal velocity gradient in the near-wall region and decrease shear stress and viscous resistance. Concurrently, owing to the decrease in the velocity gradient, shear action is weakened, and the vortices' level of stretch is reduced in the near-wall region of the grooved surface. The groove structures change the distribution of the shear layers in the boundary layer and increase the stability of the strips. The reduction of spanwise vorticities delayed the formation of hairpin vortices caused by the instability of strips and so on; and the energy dissipation is effectively reduced in the flow process.