In the impingement experiments, the spray were impinged on the wall using a single hole, spray kept on moving alone the wall, and vortex was observed as a result of gas resistance and wall friction.

• 油束撞击到平板受到平板的限制，形成壁面喷射，油束沿壁面运动，由于受到壁面上方空气的阻力而部分油束脱离平板形成“卷毡”现象，油束卷起的高度即壁面高度远小于壁面贯穿距离。