September 27
A one-dimensional stochastic model of multi-scale dynamics in turbulent flows
Dr Alan Kerstein
SANDIA National Laboratory, Livermore, CA
One computational strategy for capturing microscale processes not affordably resolved in multidimensional turbulence simulations is to represent these processes by a lower-dimensional formulation. An approach formulated in one spatial dimension, denoted One-Dimensional Turbulence (ODT), is outlined. ODT combines two 1D approaches that have individually proven successful: stochastic iterated maps and reduction of the governing equations using the boundary-layer approximation. Within ODT, subprocesses based on these two approaches are coupled so as to represent both turbulent cascade dynamics and microphysics at dissipative scales, with strong two-way interaction. Model performance in a geophysical context is illustrated by applications to building-block flows (Kelvin-Helmholtz instability, Rayleigh convection) and to geophysically relevant phenomena (e.g., multicomponent convection). Combustion applications and subgrid-scale implementation of ODT within multidimensional simulations are also discussed.
11:00 a.m., 234 Ames Hall