Flow development over isolated, surface-mounted, droplet-inspired three-dimensional obstacles submerged in a laminar boundary layer is investigated at a Reynolds number based on obstacle height of ${\mathrm{Re}}_h=2070$ using particle image velocimetry. Three geometries are considered, a sessile droplet; a droplet on the verge of runback (depinning); and a spherical cap, which serves as a first order approximation of a sessile droplet. For all three models a horseshoe vortex system forms at the leading edge and wraps around the obstacle, with the sessile model producing the most prominent horseshoe system due to its relatively high fore-body bluntness. Shear layer vortices shed from the objects form arch vortices, which produce mean streamwise vortices in wakes of the models. Downstream of the objects, turbulent fluctuations grow in a wedge shape. The spreading mechanisms in the wall-normal and lateral directions are explored through proper orthogonal decomposition of the velocity fluctuations. The analysis shows that wall-normal growth is associated with shear layer vortex breakdown, while lateral spreading is influenced by interactions between the horseshoe vortex system and streamwise wake vortices. Overall, similarity between the chopped and sessile model flow fields suggest the spherical cap is a reasonable first order approximation of a sessile droplet from a vortex dynamics perspective. Shear layer vortices shed from the runback model exhibit more complete merging than for the other two models, perhaps due to the smaller radius of curvature at the object peak. This model also exhibits a more muted horsheshoe vortex system and narrower near-field wake than the sessile model, suggesting less disruption to the incoming boundary layer flow.

根据障碍物高度，以雷诺数研究淹没在层状边界层中的孤立的，表面安装的，液滴启发的三维障碍物上的流动发展 ${\mathrm{回覆}}_H=2070$使用粒子图像测速仪。考虑了三个几何形状，无柄液滴；一滴落在倒流（销钉）的边缘；球形帽，作为无柄液滴的一阶近似。对于这三个模型，马蹄形涡流系统都在前缘形成并环绕障碍物，而无柄模型由于前躯相对较高的钝度而产生了最突出的马蹄形系统。从物体散落的剪切层涡流形成弓形涡流，在模型唤醒时会产生平均的流向涡流。在物体的下游，湍流起伏呈楔形。通过适当的速度波动正交分解，探索了在壁法线方向和横向方向上的扩展机制。分析表明，壁面法向生长与剪切层涡旋破裂有关，而横向扩展受马蹄涡旋系统与沿流尾流涡旋之间相互作用的影响。总体而言，切碎和无柄模型流场之间的相似性表明，从旋涡动力学的角度来看，球形帽是无柄液滴的合理的一阶近似。与其他两个模型相比，从缩径模型掉落的剪切层涡流显示出更完整的合并，这可能是由于对象峰处的曲率半径较小所致。与无柄模型相比，该模型还显示出更静音的马蹄形涡流系统和更窄的近场尾流，表明对进入的边界层流的干扰较小。而横向扩展受马蹄涡流系统和流向尾流涡流之间相互作用的影响。总体而言，切碎和无柄模型流场之间的相似性表明，从旋涡动力学的角度来看，球形帽是无柄液滴的合理的一阶近似。与其他两个模型相比，从缩径模型掉落的剪切层涡流显示出更完整的合并，这可能是由于对象峰处的曲率半径较小所致。与无柄模型相比，该模型还显示出更静音的马蹄形涡流系统和更窄的近场尾流，表明对进入的边界层流的干扰较小。而横向扩展受马蹄涡流系统和流向尾流涡流之间相互作用的影响。总体而言，切碎和无柄模型流场之间的相似性表明，从旋涡动力学的角度来看，球形帽是无柄液滴的合理的一阶近似。与其他两个模型相比，从缩径模型掉落的剪切层涡流显示出更完整的合并，这可能是由于对象峰处的曲率半径较小所致。与无柄模型相比，该模型还显示出更静音的马蹄形涡流系统和更窄的近场尾流，表明对进入的边界层流的干扰较小。切碎的和无柄的模型流场之间的相似性表明，从旋涡动力学的角度来看，球形帽是无柄液滴的合理的一阶近似。与其他两个模型相比，从缩径模型掉落的剪切层涡流显示出更完整的合并，这可能是由于对象峰处的曲率半径较小所致。与无柄模型相比，该模型还显示出更静音的马蹄涡系统和更窄的近场尾流，这表明对进入的边界层流的干扰较小。斩波模型和无柄模型流场之间的相似性表明，从旋涡动力学的角度来看，球形帽是无柄液滴的合理的一阶近似。与其他两个模型相比，从缩径模型掉落的剪切层涡流显示出更完整的合并，这可能是由于对象峰处的曲率半径较小所致。与无柄模型相比，该模型还显示出更静音的马蹄形涡流系统和更窄的近场尾流，表明对进入的边界层流的干扰较小。