Physics Department and the James Franck Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.
Phys Rev Lett. 2010 Jan 22;104(3):034504. doi: 10.1103/PhysRevLett.104.034504. Epub 2010 Jan 21.
We simulate the impact of a viscous liquid drop onto a smooth dry solid surface. As in experiments, when ambient air effects are negligible, impact flattens the falling drop without producing a splash. The no-slip boundary condition at the wall produces a boundary layer inside the liquid. Later, the flattening surface of the drop traces out the boundary layer. As a result, the eventual shape of the drop is a "pancake" of uniform thickness except at the rim, where surface tension effects are significant. The thickness of the pancake is simply the height where the drop surface first collides with the boundary layer.
我们模拟了粘性液滴撞击光滑干燥固体表面的情况。与实验一样，当环境空气的影响可以忽略不计时，撞击会使下落的液滴变平，而不会产生飞溅。壁面的无滑移边界条件会在液体内部产生边界层。随后，液滴的变平表面会勾勒出边界层的形状。因此，液滴的最终形状是一个厚度均匀的“薄饼”，除了边缘，那里的表面张力影响显著。薄饼的厚度就是液滴表面与边界层首次碰撞的高度。
