Presidential Young Investigator Award: (1) Combined Con- vection from a Rotating Cylinder 2) Double Diffusion in a Fluid Layer Superposing a Porous Layer

本文的研究主要集中在两个方面，第一个领域是关于旋转水平圆柱体的自由-强迫联合对流。该研究是以空气为工质，利用现有风洞模拟强迫对流进行的实验研究。对圆柱体进行电加热，并在圆柱体边界上保持恒定热流条件。计算结果充分反映了雷诺数、瑞利数和圆柱角速度对流场和温度场的影响。第二个研究领域涉及由垂直方向上的温度和浓度梯度的共同作用引发的多孔层和流体层中的对流不稳定性。在理论研究中，确定了产生对流运动的系统的临界参数，以及这些运动的性质。理论结果与实验测量结果进行了对比验证。

The research focuses on two areas, the first dealing with combined free-forced convection from a rotating horizontal cylinder. The study is experimental and is carried out by using air as the working fluid and an existing wind tunnel to simulate the forced convection flow. The cylinder is heated electrically and the constant heat flux condition is maintained on the cylinder boundary. The results document thoroughly the effect of the Reynolds number, the Rayleigh number, and the angular velocity of the cylinder on the temperature and flow fields. The second area of research concerns convective instability in superposed porous and fluid layers triggered by the combined action of temperature and concentration gradients in the vertical directions. In the theoretical investigation, the critical parameters of the system which yield convective motions are determined, as well as the nature of these motions. The theoretical findings are tested against experimental measurements.