If a body enters a viscous-inviscid fluid layer near a wall, then significant effects can be felt from the presence of incident vorticity, viscous forces and nonlinear forces. The focus here is on the response in the outer edge of such a wall layer. Nonlinear two-dimensional unsteady behaviour is examined through modelling, computation and analysis applied for a thin body travelling streamwise upstream or downstream or staying still relative to the wall. The wall layer with its balance between inviscid and viscous effects interacts freely with the body movement, causing relatively high magnitudes of pressure on top of the body and nonlinear responses in the gap between the body and the wall. The study finds explicit solutions for the motion of the body, separation of the flow arising near the wall and possible instabilities occurring over the length scale of any short body.

中文翻译：

---

当一个小的薄二维体进入粘性壁层时

如果物体进入壁附近的粘性非粘性流体层，则可以从入射涡度、粘性力和非线性力的存在中感受到显着的影响。这里的重点是这种墙层外边缘的响应。非线性二维非定常行为是通过建模、计算和分析来检查的，适用于沿流向上游或下游移动或相对于壁保持静止的薄体。壁层在无粘性和粘性效应之间取得平衡，与身体运动自由相互作用，在身体顶部产生相对较高的压力，并在身体和壁之间的间隙中产生非线性响应。该研究为身体的运动找到了明确的解决方案，