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

摘要： 流向的微小沟槽表面能有效降低壁面摩阻，降低输送能耗。针对内表面有三角形肋条的输气管道，采用大涡模拟对不同流动状态进行模拟，分析了流场速度矢量图、均方根速度剖面线和雷诺切应力。结果表明，肋条无量纲尺寸s＋＝20.7时肋条的减阻效果最好；湍流形成的涡经过肋条时被肋峰切开在肋条中形成小的反向小涡，将流体与壁面之间的滑动摩擦转变为滚动摩擦，降低摩擦阻力；光滑管壁、肋条的肋峰和谷底表面的速度剖面线只有在壁面附近差别较大，在远离壁面处趋于一致，肋条对流场的影响主要发生在近壁区。

关键词: 肋条减阻, 大涡模拟, 二次涡, 无量纲尺寸