Turbulence informed models for shallow water simulations of turbidity currents

Principal Investigator: S. "Bala" Balachandar

Sponsor: ExxonMobil Upstream Research Company

Start Date: September 22, 2014

End Date: May 31, 2021

Amount: $869,501

Abstract

Turbidity currents at geophysical scale are highly nonlinear turbulent multiphase flows. The dynamics of these flows involve tight interactions of the phases over a wide range of length and time scales. Furthermore, the interactions of the turbidity currents with the bed at the bottom and with the ambient along the upper boundary are of great relevance in the development and dynamics of turbidity currents. Accurate prediction of these flows demands models that accurately account for all the basic physical processes involved. In this work we propose to use direct and large eddy simulation methodologies with immersed boundary method capabilities to examine the following key physical processes: (a) dependence of local bed erosion on instantaneous shear stress and pressure fluctuation, (b) turbulence modulation and suppression of turbulent production/transport by particle-induced density stratification, (c) entrainment of ambient fluid in the context of a self-stratified particle-laden interface, and (d) the formation/evolution of different types of bedforms under various flow conditions. The ultimate goal is to advance systematic improvements to Parker-type shallow water models (Parker et al, 1986) that incorporate the above physics and validate them against available data.