[Objectives]To investigate the near-wall rotating cylindrical wake and hydrodynamic character-istics,flow around cylinder at typical gap ratios is investigated.[Methods]A numerical simulation of flow around a near-wall rotating cylinder with different gap ratios(G/D = 0.2,0.8,1.4)and rotation rates at Reyn-olds number Re=200 was carried out to compare the cylindrical wake and hydrodynamic characteristics at dif-ferent gap ratios and rotation rates.[Results]The results show that:For G/D=0.2,the cylindrical vortex shedding is significantly suppressed and the lift and drag force on the cylindrical surface remain steady.For G/D=0.8 and G/D=1.4,at low rotation rates,the"wake vortex"is shed and is similar to the 2S pattern,with sinusoidal periodic fluctuations in the lift and drag coefficients and small amplitude;at higher positive rotation rates,the cylindrical wake pattern is the stable D pattern with no vortex shedding(changing from D+ to D-pat-tern as the rotation rate increases),the"wake vortex layer"is separated from the"wall vortex layer",the"wall vortex"is shed multi-periodically,the lift and drag coefficients are fluctuating multi-periodically and the amp-litude is increasing significantly;at higher reverse rotation rates,the cylindrical surface is wrapped by a posit-ive boundary layer,with no vortex shedding and no fluctuations in lift and drag.[Conclusions]The results can provide a reference for the development of high efficient flow control technology.
关键词
圆柱绕流/旋转/近壁圆柱/升阻力/涡层分离
Key words
flow around cylinder/rotating/near-wall cylinder/lift and drag force/vortex layer separation
维普
万方数据