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

Lehigh University, Bethlehem PA

Investigators

Abstract

1453056 Banerjee The 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.