Exact Moment Closure for a General Rapidly Fluctuating Random Flow Field by Rich McLaughlin JWB 335, 3:20pm Monday, November 6, 1995 Abstract An important problem is the understanding of the statistics a passive scalar inherits from some prescribed random flow field. This problem is extremely complicated because of closure problems. However, in certain situations, exact full moment closure is available. In this talk I will first review the case of a shear layer rapidly fluctuating in time. In this case, closure is obtained through the Feynman-Kac's path integral and illustrates an important connection to N-body quantum mechanics. Then, I will consider the case of a more general flow field rapidly fluctuating in time. New results obtained jointly with Jared C. Bronski will be presented demonstrating the use of a path integral representation for a charged particle in a magnetic field to obtain a closed evolution equation for the mean statistics. Then, to obtain closed equations for the N point correlation function, I will present a clean prescription based upon the underlying discrete process. Finally, in joint work with Jared Bronski and Davar Khoshnevisan, I will discuss intermittency issues for these general flows. Included will be an attempt to obtain long time asymptotics using homogenization, as well as a picture of intermittency involving the ground state energy of interacting particles. Requests for preprints and reprints to: rmm@math.utah.edu