○ 2月1日 (水) （以下の講演は、講演者体調不良のため、中止になりました。）

15:00 ～16：00 
Speaker 
Snezhana I. Abarzhi
University of Chicago 
Title 
Turbulent mixing and beyond: problems, concepts, solutions 
Abstract 
Turbulent mixing plays an important role in a broad variety of natural and artificial systems, spanning astrophysical to atomistic scales and low to high energy densities. Examples include inertial confinement fusion, supernovae, stellar convection, noncanonical boundary layers and optical
freespace communications. Theoretical description of nonequilibrium mixing transports is a challenging problem due to singular aspects of the governing (Euler or NavierStokes) equations. Furthermore these processes are statistically unsteady and their fluctuating quantities are
essentially timedependent and nonGaussian. We apply the new theoretical concept, the rate of momentum loss, to describe the transports of mass, momentum and energy in turbulent mixing flow and to capture its anisotropic and inhomogeneous character. It is shown that invariant,
scaling and spectral properties of unsteady turbulent mixing differ substantially from those of isotropic and homogeneous turbulence. Timeand scaleinvariance of the rate of momentum loss leads to nondissipative momentum transfer, to 1/2 and 3/2 powerlaw scaledependencies of the
velocity and Reynolds number and to nonKolmogorov spectra. Turbulent mixing exhibits more order compared to isotropic turbulence, and its viscous and dissipation scales are finite and set by flow acceleration. We suggest how to describe the random character of the statistically unsteady
turbulent flow and show that the rate of momentum loss is the dynamic invariant and a robust diagnostic parameter for either sustained or timedependent acceleration. Some criteria are outlined for the estimate of the fidelity and information capacity of the experimental and numerical
data sets. 




