Laminar cross-flow over a circular cylinder with smooth as well as longitudinally grooved surfaces was investigated numerically for low freestream Reynolds number ranging from 50 to 300. Most of the currently published works on similar flow configurations considered high Reynolds number in the turbulent regime. The computations were performed by the ANSYS Fluent code. The numerical results were validated against the experimental results. The triangular V-shaped, the U-shaped, and Rectangular shaped grooves, with unit aspect ratio; along with the smooth cylinder, are considered. The predicted flow-field for the grooved cylinder cases are analyzed and compared with that for the smooth cylinder. The aerodynamic loads, time-averaged velocities, rms velocity, vorticity, and pressure coefficient plots around the smooth and grooved cylinders were compared to explore the effect of the shape of the grooves on flow dynamics over the cylinder. The flow physics around the cylinder is significantly affected by the shape and size of the grooves, and their circumferential distribution. It is found that the U-grooves significantly decrease the mean drag coefficient (around 13% for $Re$ $=$ 200 and 10% for $Re$ $=$ 300 compared to the smooth cylinder case). The grooves decreased viscous drag significantly (up to 30%) compared to pressure drag. The grooves on the cylinder also delayed the separation and reduced the extent of the recirculation zone in the cylinder wake due to the presence of recirculating flow within the individual grooves. The conclusion is that the properly designed longitudinal grooves on the cylinder in a cross-flow can be used advantageously for reducing aerodynamic loads like drag and lift force in laminar flow as well.

对于从 50 到 300 的低自由流雷诺数，对具有光滑和纵向凹槽表面的圆柱体上的层流交叉流进行了数值研究。目前发表的大多数关于类似流动配置的著作都考虑了湍流状态下的高雷诺数。计算由 ANSYS Fluent 代码执行。数值结果与实验结果进行了验证。具有单位纵横比的三角形V形、U形和矩形凹槽；与光滑的圆柱体一起考虑。分析了带槽圆柱体的预测流场，并与光滑圆柱体的流场进行了比较。空气动力载荷、时间平均速度、均方根速度、涡度、比较光滑圆柱体和带凹槽圆柱体周围的压力系数图，以探索凹槽形状对圆柱体上流动动力学的影响。圆柱体周围的流动物理受凹槽的形状和尺寸及其圆周分布的显着影响。发现 U 形槽显着降低了平均阻力系数（大约 13%）$\mathrm{电阻}\mathrm{电子}$ $=$ 200 和 10% $\mathrm{电阻}\mathrm{电子}$ $=$300 与光滑的圆柱外壳相比）。与压力阻力相比，凹槽显着降低了粘性阻力（高达 30%）。由于各个凹槽内存在再循环流，气缸上的凹槽也延迟了分离并减少了气缸尾流中再循环区域的范围。结论是，适当设计的横流中圆柱体上的纵向凹槽也可有利地用于减少空气动力载荷，例如层流中的阻力和升力。