AI 中文总结
本研究开发定制化旋转单热线探针，探究斜置小肋引发的近壁流动转向规律，发现直置转斜置小肋的展向速度分布符合SSL解，斜置转直置的流动恢复存在空间滞后且残余展向流动持续存在。
AI 中文摘要
本研究探究了由大间距斜置小肋（riblets）引发的近壁流动转向的空间发展与恢复规律。为精确测量近壁区的平均展向速度，我们开发了一种独特的定制化旋转探针，该探针配备单热线。这项新技术展现出高灵敏度，可可靠检测微小的展向速度分量。我们运用该探针绘制了直置转斜置小肋、斜置转直置小肋构型的流动图谱。对于直置转斜置的过渡情况，平均展向速度的下游分布与阶跃强制空间斯托克斯层（SSL）解高度吻合，实现了等效主动壁面运动$V^+_\text{equ} \approx 2.0$，这为未来被动流动控制研究提供了简化的分析途径。相反，斜置转直置构型的流动恢复与SSL阶跃下降阶段的预测结果存在偏差；研究观测到空间滞后现象： crest（峰脊）附近的流动恢复迅速，但显著的残余展向流动（$V^+ > 0.5$）在远下游（$\text{widehat}\{x\}{}^+ > 1000$）仍持续存在。
英文摘要
This study investigates the spatial development and recovery of near-wall flow steering induced by yawed widely-spaced riblets. To accurately measure the mean spanwise velocity in the near-wall region, we developed a unique, customised rotating probe equipped with a single hot-wire. This novel technique demonstrates high sensitivity, reliably detecting small spanwise velocity components. We applied this probe to map the flow over straight-to-yawed and yawed-to-straight riblet configurations. For the straight-to-yawed transition, the downstream distribution of the mean spanwise velocity closely aligns with the step-forced spatial Stokes layer (SSL) solution, achieving an equivalent active wall motion of $V^+_\mathrm{equ} \approx 2.0$. This offers a simplified analytical pathway for future passive flow manipulation studies. Conversely, flow recovery over the yawed-to-straight configuration diverges from the SSL step-down phase prediction. Instead, a spatial lag was observed where crest-adjacent flow recovered quickly, but significant residual spanwise flow ($V^+ > 0.5$) persisted far downstream ($\widehat{x}{}^{+} > 1000$).
Comments10 figures; 13 pages
