A combination of time-resolved particle image velocimetry (TR-PIV) and tomographic PIV was used to study the instantaneous 3D vortex shedding as well as mean velocities and turbulent stresses in the near wake of a smooth and rough sphere. Sphere roughness was modeled by spiraling grooves found in nature on pine cones. The measurements extended up to five sphere diameters, $D$, downstream of the sphere, and were performed across a Reynolds number range of $226

中文翻译：

---

光滑球体附近和模仿松锥的流测量

将时间分辨粒子图像测速仪（TR-PIV）和断层成像PIV结合使用，研究了在光滑粗糙的球体附近的瞬时3D涡旋脱落以及平均速度和湍流应力。通过在松果上自然界中发现的螺旋形凹槽来模拟球体粗糙度。测量范围扩大到五个球体直径，$d$，在球体的下游，且雷诺数范围为226美元