关键词: 肋条减阻, 大涡模拟, 二次涡, 无量纲尺寸

Abstract: The small groove surface flowing in the direction can effectively reduce the wall friction and reduce the energy consumption of transportation. For the gas pipeline with triangular ribs on the inner surface, the large eddy simulation is used to simulate different flow states, and the flow field velocity vector diagram, root mean square velocity profile line and Reynolds shear stress are analyzed. The simulation results show that the best drag reduction effect is achieved when the dimensionless dimension s+=20.7; the vortex formed by the turbulence is cut by the rib peak when passing through the rib to form a small reverse small vortex in the rib, and the fluid is the sliding friction between the wall surfaces which is converted into rolling friction, which reduces the frictional resistance; the velocity profiles of smooth tube wall, rib peak and valley bottom surface only differ greatly near the wall surface, and tend to be consistent far from the wall surface, and the rib pair the influence of the flow field mainly occurs in the near wall area.

Key words: Rib drag reduction, Large eddy simulation, Secondary vortex, Dimensionless size