CAREER: Transition to Turbulence and Mixing for Rayleigh Taylor Instability with Acceleration Reversal

1453056 Banerjee这项建议的重点是使用计算和实验组件来阐明变密度湍流中的混合(即，不同密度的两种流体由于湍流而混合)。以前在这一领域的大部分研究都集中在质量传输不影响流场的较简单情况下，以及正则流(例如，槽道流、射流、边界层)。这项拟议的研究旨在克服与非正则流动(这些流动是工业和自然界中常见的流动)实验研究相关的困难，并在新的环境下以前所未有的细节测量湍流量。这项工作可以开拓流体动力学的其他领域的发展，包括多相流、热传递和燃烧以及激波驱动的流动。拟议的教育活动包括让当地一所社区学院参与国际和平协会的研究，制作一系列教育视频，并通过iTunes提供，以及将8至12年级的学生纳入夏令营进行研究。本研究的目的是通过实验和模拟来研究变密度流中的Rayleigh-Taylor不稳定性。当两种不同密度的流体接触时，这种不稳定性就会发生，密度较高的流体会被较轻的流体加速。PI建造了一个相当独特的实验设施，使他能够完成拟议工作的实验部分。它是一种可以控制旋转系统中流体的加速和减速的装置。该实验系统甚至允许从加速切换到减速，然后进一步反向加速。PI建议使用平面激光诱导荧光、PLIF和立体粒子图像测速技术来获得流场和标量场的高阶统计量。为了用最先进的模拟来补充实验，PI与LANL建立了合作关系，对流动进行直接数值模拟(DNS)。

1453056BanerjeeThe focus of this proposal is to use both computational and experimental components to elucidate mixing in variable density turbulence (i.e., when two fluids of different density mix because of turbulence). The bulk of prior research in this area has focused on the easier case of transport of mass without effects on the flow field, and on canonical flows (e.g., channel flows, jet flows, boundary layers). The proposed research aims to overcome the difficulties associated with experimental studies of non-canonical flows (these flows are the ones commonly found in industry and in nature), and to measure turbulence quantities in unprecedented details in new settings. Such work can open up developments in other areas of fluid dynamics, including multiphase flow, heat transfer and combustion and shock-driven flows. The proposed educational activities include the involvement of a local community college in the PI's research, the development of an educational video series that would be available through iTunes, and the inclusion of 8th to 12th graders in summer camps for research. The goal of the proposed research is to investigate the Rayleigh-Taylor instability in variable density flows using both experiments and simulations. This instability occurs when two fluids of different density are in contact, and the denser fluid is accelerated by the lighter fluid. The PI has built a rather unique experimental facility that would enable him to complete the experimental part of the proposed work. It is a device that allows the control of acceleration and deceleration of the fluid in a rotating system. The experimental system even allows the switch from acceleration to deceleration and then further reversals of acceleration. The PI proposes the use of planar laser-induced fluorescence, PLIF, and stereo-Particle Image Velocimetry to obtain high order statistics for the flow and scalar fields. In order to complement the experiments with state-of-the-art simulations, the PI has established a collaboration with LANL to conduct direct numerical simulations (DNS) of the flow.