MRI: Instrumentation for Large Scale Holographic Particle Image Velocimetry with a Sample Volume of 25x25x25 cm^3, 500^3 Velocity Vectors and High Speed Data Processing System

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Abstract CTS-0079674 J. Katz, Johns Hopkins University The objective of this project is to develop and implement a large scale Holographic Particle Image Velocimetry (HPIV) system for measuring complex turbulent flows. The data will be used for addressing fundamental turbulence modeling questions. The system will enable measurements of the instantaneous, three-dimensional velocity distribution over sample volumes of up to 25x25x25 cm^3, at an unprecedented resolution in scale, with arrays of 500x500x500, 3-D velocity vectors. Efficient and high speed processing tools will enable analysis of many holograms. Two main avenues of turbulence research provide motivation: i) scaling dynamics and statistical geometry of velocity increments in high Reynolds number turbulent flows, and ii) relationships between large and small scales in turbulence and their implications for subgird-scale modeling for Large Eddy Simulations (LES). The 3-D data will enable the PI and his colleagues to address the anomalous scaling behavior of high order structure functions that significantly deviate from Kolmogorov's predictions; Turbulence modeling for LES must be based on understanding of the interactions among turbulent motions at various length-scales. Such understanding requires data consisting of well-resolved velocity fields that can be the filtered to obtain the subgrid scale stresses, filtered velocity and its gradients. Development and improvements to this technology would eventually make it available to an entire community of researchers in a wide range of fields where transport phenomena are of significance. Included are communities involved in fundamental and applied fluid mechanics, multiphase flows involving transport of bubbles, particles and droplets as well as environmental flows, such as sediment transport, atmospheric sciences (turbulence and particle transport) and oceanography flow, particles and plankton dynamics, etc.).