Experiment and Nemerical Prediction for Onset of od Three Diemnsional Separation

在助学金的有效期内，核实或设计了下列项目。1.提出了一种简单的可视化技术，该技术提供了拖曳水槽中沿模型限制流线的示踪剂记录，采用电解法将酚醛树脂溶液涂在物体表面。以轴对称抛物面和垂直于平板的圆柱为例，给出了可视化结果。对于高达62°左右的闭合分离线的临界角，回转抛物面的计算结果与Bippes的计算结果吻合较好。采用氢气泡方法对流场中的旋涡进行可视化，对于抛物面的情况，可以观察到侧向旋涡的交替脱落。在风洞中测量了抛物面上的静压，证实了主分隔线后面存在着与二维层序一样的天青石分布平台。对于圆柱板结合部附近的流动，可以观察到结点、鞍点和焦点，焦点的位置随着圆柱体后孪生涡长度的变化而周期性移动。针对三维Navier-Stokes方程的有限差分计算结果和边界层解，发展了计算机图形学中的三维流动图解技术。

During the term of the Grant-in -aid the following items are verified or devised. 1. A simple Visualization technique is proposed which provides a record of tracer for the limitting streamlines along a model in a towing tank.Electrolysis method is applied with painting the phenolphtalein solution on a body surface. The visualization results over axisymmetric paraboloid and along a circular cylinder normal to flat plate are shown as examples.2. The results for paraboloid of revolution show a good agreement with those by Bippes as for the critical angles for the onset of closed separation line as high as 62 deg or so.3. Hydrogen bubble methods is also applied to visualize vorticis in the flowfields.For the case fo paraboloid the alternative shedding of lateral vortices canbe observed.4. Static pressure over the paraboloid was measured in a wind tunnel and a plateau of azunytgak oressyre distribution as in 2-D seqaration was confirmed behind primary separatin lines.5. As for the flow near the cylinder-plate juncture the nodes,saddles,and foci can be observed.The locations of foci move cyclically with the length of twin vortices behind the cylinder.6. Illustrating techniques of three dimensional flows in computer graphics are developed for the results of finite difference computation for tridimensional Navier Stokes equations as well as boundary layer solutions.