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Direct numerical simulation of droplet-laden isotropic turbulence

Event Type: 
Date and Time: 
Friday, June 2, 2017 - 16:15
CTR Conference Room 103
Event Sponsor: 
Parviz Moin, Director of Center for Turbulence Research
Michael S. Dodd, Department of Aeronautics and Astronautics, University of Washington

Understanding how droplets and turbulence interact is important in numerous applications ranging from rain formation to oil spills to spray combustion, yet most of our knowledge of two-phase turbulence is limited to solid particles. In contrast to solid particles, droplets introduce new phenomena and parameters into the flow, e.g., droplets can deform, break up, coalesce, develop internal circulation, and change phase. In this talk, Dodd will review efforts towards improved understanding of droplet-turbulence interaction. Dodd uses direct numerical simulation (DNS) to capture the exchange of momentum, heat, and mass between the droplets and surrounding flow, while fully resolving the turbulence. First, Dodd will show DNS results of non-evaporating droplets of Taylor length scale size in decaying isotropic turbulence. The pathways for turbulent kinetic energy (TKE) exchange between the turbulent carrier flow and the flow inside the droplets will be explained starting from TKE budget equations. Dodd will show how increasing the viscosity ratio between the droplets and carrier fluid increases the decay rate of TKE and explain the underlying physical mechanisms. Second, Dodd will present preliminary results of DNS of evaporating droplets in isotropic turbulence.

Michael S. Dodd is a Ph.D. Candidate in the Department of Aeronautics and Astronautics at the University of Washington. He earned his B.S. in Aerospace Engineering from the University of Michigan. Dodd uses direct numerical simulation to gain fundamental understanding of droplet-turbulence interaction. He also works on developing numerical methods for gas-liquid turbulent flows.