NSF Young Investigator

这项研究在明年将包括实验流体力学领域的几个项目：固体表面附近的颗粒-湍流相互作用、模型下击暴流的研究、尾缘几何形状对射流混合的影响以及流动结构对液体喷雾的影响。在第一组实验中，我们研究了粒子在轻负荷撞击射流中的运动。粒子图像和粒子跟踪测速仪被用来测量已知尺度的相干涡旋存在时的粒子速度和轨迹。高颗粒质量负荷的单独实验将尝试检查颗粒对湍流的修改以及当撞击表面被加热时所产生的任何换热修改。在下击暴流研究中，我们将用PIV获得水平速度场，以考察方位不稳定性和近地速度梯度的发展。在射流研究中，我们将进行流动显示和速度测量，以了解具有阶梯和锯齿形尾缘的圆形射流中参数对混合的影响。最后，我们将设计和建造一个用于研究不同湍流度和结构的喷雾的装置。

ABSTRACT CTS-9457014 University of Minnesota P.I.: Ellen Longmire This research over the next year will include several projects in the field of experimental fluid mechanics: Particle-turbulence interaction near solid surfaces, investigation of model downbursts, effects of trailing edge geometry on jet mixing, and the effect of flow structure on liquid sprays. In the first set of experiments, we are examining the motion of particles in a lightly-laden impinging jet. Particle image and particle tracking velocimetry are use to measure particle velocities and trajectories in the presence of coherent vortices of known scale. Separate experiments with high particle mass loadings will attempt to examine turbulence modification by the particles and any resulting heat transfer modification when the impingement surface is heated. In the downburst study, we will obtain horizontal velocity fields with PIV to examine both the development of azimuthal instabilities and near-ground velocity gradients. In the jet study, we will perform flow visualization and velocity measurements to understand parametric effects on mixing in round jets with stepped and sawtooth trailing edges. Finally, we will design and construct a facility for the study of sprays subject to varying turbulence level and structure.