MRI: Acquisition of Instrumentation on Experimental Studies on Interactions of Unsteady Flows and Dynamical Boundaries

该合同将使购买粒子成像速度（PIV）系统，通用研究显微镜，流变仪和一些较小的设备成为可能。有了这些仪器，研究人员将研究一些流体问题，涉及非定常流体流动与移动的边界相互作用。特别是，计划研究以规定波形拍打的刚性机翼的自由飞行。PI将解决与在机翼开始单向飞行的早期阶段产生推力有关的问题。他们还将研究能够在飞行过程中俯仰的扑翼的效果，并将其性能与非俯仰翼进行比较，以及与扑翼相关的不稳定性以及强制旗帜产生不同类型的尾流结构的机制。这个实验将解决的问题之间的联系和差异，一个挥舞的旗帜和游泳的鱼。此外，众所周知，流体泵送和动物运动有许多共同的方面，并且可以使用类似的理论处理来研究。计划中的研究将使用各向异性几何（棘轮）和模式生物（C。elegans）在粘性流体中。研究将扩展到复杂的流体，因为非线性响应发生在这些系统中，即使在低雷诺数。所要求的仪器将在应用数学实验室（AML）实现根本性的改进，这将允许以更高的精度和灵活性调查移动流体中的动态边界问题。研究项目将涉及各级科学家，从教职员工到积极的本科生和高中生。

This award will make possible the purchase of a system of Particle Imaging Velocity (PIV), a universal research microscope, a rheometer and a few smaller equipments. With these instrumentations, the investigators will study a number of fluid problems that involve unsteady fluid flows interacting with mobile boundaries. In particular, it is planned to study the free flight of a rigid wing that is flapped at prescribed wave forms. The PIs will address questions related to the generation of thrust at early stages as the wing initiates a unidirectional flight. They will also study the effects of a flapping wing that is able to pitch during its flight, and compare its performance to a non-pitching wing, as well as the instability associated with flapping flags and the mechanism by which forced flags produce different types of wake structures. This experiment will address the question of the connections and differences between a flapping flag and a swimming fish. Moreover, it is well known that fluid pumping and animal locomotion share many common aspects, and can be studied using similar theoretical treatments. The planed study will investigate the transport of fluid using anisotropic geometry (ratchets) and the swimming of a model organism (C. elegans) in viscous fluids. The studies will be extended to complex fluids, since nonlinear responses take place in these systems even at low Reynolds numbers. The requested instrumentations will realize a fundamental improvement at the Applied Mathematics Laboratory (AML), which will allow the investigation of dynamical boundary problems in moving fluids with added precision and flexibility. The research projects will involve scientists at all levels, ranging from faculty members to motivated undergraduate and high-school students.