低雷诺数下并列双波浪柱尾迹干扰效应数值模拟

该文针对雷诺数Re=100下不同波长参数(/mλD=2、4、6和8)、不同间距比(1.5/3.5m≤L D≤)的并列双波浪柱后尾迹复杂的三维流动结构及干扰效应进行了数值研究。研究表明:三维并列双波浪柱在较小的间距比/1.5mL D=时,波峰对波谷排列的并列波浪柱后尾迹呈现明显偏置双稳流动结构,而波峰对波峰排列工况下基本呈现单一波浪型钝体后尾迹流动结构(尤其是在大波长/mλD=6和8时);当间距比/3mL D≥时,随着波长/mλD的增大,上下波浪柱各自呈现单波浪柱后尾迹流动结构;较大波长的三维波浪形状更好地组织了后尾迹三维流动结构,减少了并列双波浪柱后尾迹的相互干扰,从而减阻减振明显,最高减阻可达14.5%,脉动升力系数上下游波浪柱均趋于0.1。该研究可为近海工程的多立管结构及悬索桥的拉索振动抑制等提供理论支持。

Numerical simulations of wake interference behind two side-by-side wavy cylinders in low Reynolds number

The numerical simulations of 3D complicated flow structures and near-wake interference behind two side-by-side wavy cylinders are conducted at a fixed Reynolds number of 100,the different dimensionless wavelengths λ/Dm from 2 to 8 and the spacing ratios L/Dm from 1.5 to 3.5.The results indicate that a biased bistable wake pattern is observed at L/Dm =1.5 for the peak to bottom (P-B) arrangement case while a similar-single wake pattern is found for the peak to peak (P-P) arrangement case at the same spacing ratio.Moreover,the interaction between the two wakes diminishes when the wavelength λ/Dm is increasing to 8 for the L/Dm ≥ 3 cases,the wake pattern behind each wavy cylinder is similar to that of the single wavy cylinder.The three-dimensional near wake structures behind the two side-by-side wavy cylinders are organized well at larger values of wavelength λ/Dm case,the drag reduction is up to 14.5％ and the r.m.s.lift coefficients of the two wavy cylinders are greatly reduced to almost 0.1.Such an investigation will offer further theoretical support in engineering applications such as the vibration control of stay cables in suspension bridges and multiple risers in offshore engineering.