SGER: DESIGNED VORTICES AND HYBRID VIRTUAL-PHYSICAL EXPERIMENTS FOR VORTEX DYNAMICS RESEARCH

CBET-0813835 Williamson这个探索性的研究项目将带来PI在基本涡流动力学、不稳定性和湍流开始方面的工作，以研究从物体的非稳定受控运动中提取推进和能量。PI还将研究涡激振动，飞行物体的动力学，以及自由上升和下降的机构。两个探索性的研究调查，应该提供相当强大的和一般的工具：第一，一个有效的方法来产生多个漩涡，可能在固体或墙壁的存在;第二，建立一个“虚拟非定常动力学设施。“关于第一种方法，而不是在事后观察涡度分布，PI将确定如何相对于流体移动物体，以提供预定的涡流配置-简而言之，实际设计涡流配置。这个想法的关键是设计一个模型的涡流形成的锋利的边缘机构。该方法涉及在水平面内平移垂直机翼（如使用巨大的XY机翼），采用康奈尔计算机控制的XY拖曳坦克。迫切需要这种方法的一个直接应用是适用于飞机尾涡尾流的涡结构，包括反向旋转或同向旋转涡的相互作用，以及它们与地面的相互作用。第二种方法涉及开发虚拟非定常动力学设施，这将允许流体中的物体移动，就好像它是弹性约束的;结构刚度，阻尼和质量在计算机内的软件中表示，而流体力和身体上的力矩是从物理身体实际测量的。主体的运动由拖曳罐运输系统计算机控制，遵循软件中表示的运动方程。PI可以通过将重力表示为水平力来实验自由上升和下降的物体！直接比较，可以与一些现有的实验研究自由动力学的球体和圆柱体。为了从涡动力学和失速的角度理解翻滚和摇摆模式，可以研究下落物体（如平板）的颤振。从1990年到2007年，PI在他的研究实验室中有177名学生参与，他将继续参与本科生，包括少数民族本科生。这些本科生中有很大一部分人在PI的实验室工作过，后来又攻读了硕士和博士学位。

CBET-0813835WilliamsonThis exploratory research project will bring the PI's work on fundamental vortex dynamics, instabilities and the onset of turbulence to study propulsion and energy extraction from unsteady controlled motion of bodies. The PI will also study vortex-induced vibration, and dynamics of flying objects, as well as freely rising and falling bodies. Two exploratory research investigations that should deliver quite powerful and general tools are: firstly, an efficient method to generate multiple vortices, possibly in the presence of solid bodies or a wall; and secondly, building a "Virtual Unsteady Dynamics Facility." Concerning the first approach, rather than observe vorticity distributions after the fact, the PI will determine how to move a body, relative to a fluid, to deliver a pre-determined vortex configuration - in short to actually design a vortex configuration. A key to this idea is to devise a model of the vortex formation from sharp-edged bodies. The approach involves translating a vertical airfoil in a horizontal plane (like one uses a giant XY plotter), employing the Cornell computer-controlled XY Towing Tank. An immediate application, where this approach is urgently needed is that of vortex configurations applicable to aircraft trailing vortex wakes, including counter-rotating or co-rotating vortex interactions, and their interaction with the ground. The second approach involves development of a Virtual Unsteady Dynamics Facility, which will allow a body in the fluid to move as though it were elastically-restrained; the structural stiffness, damping and mass are represented in software within a computer, while the fluid forces and moments on the body are those actually measured from the physical body. The motion of the body is computer-controlled by the towing tank carriage system, following the equations of motion represented in the software. The PI can experiment with freely rising and falling bodies by representing gravity as a horizontal force! Direct comparison can be made with some existing experiments studying free dynamics of spherical and cylindrical bodies. Flutter of falling bodies such as plates can be studied with a view to understanding tumbling and rocking modes in terms of the vortex dynamics and stall. The PI has involved 177 students in his research laboratories from 1990-2007, and his involvement with undergraduates, including minority undergraduates, will continue with this project. A large proportion of those undergraduates, whose experience has been in the PI's laboratories, have gone on to Masters and PhD degrees.