2018 Physics/Theoretical Colloquium
 
Thursday, April 5th, 2018
3:45 – 4:45 p.m.
Rosen Auditorium (TA-53, Bldg. 1)
Refreshments at 3:15pm
 
Speaker: Dr. Kathy Prestridge
 
P-23: NEUTRON SCIENCE & TECHNOLOGY
Los Alamos National Laboratory
 
 
 
“Mixing and Turbulence: Are we there yet?”
 
Abstract: 
 
Variable-density flows, from stars to inertial confinement fusion capsules, present challenges for numerical modeling and simulation. We are performing several different types of experiments to understand the effects of initial conditions on subsonic and shock-driven variable-density flows in a wide range of flow conditions, from transitional to turbulent flows, and with high density ratios (4:1). Shock tube experiments allow us to explore the effects of Mach number and initial conditions on unsteady variable-density mixing, and wind tunnel experiments using jets allow us to make detailed measurements that are still difficult in shock tubes. Explosively-driven experiments put us into regimes of high Mach number (Mach 9) and Atwood numbers close to one in gases, but they present new measurement challenges. Diagnostic developments are allowing us to measure turbulence quantities important to mixing for the first time in flows in shock tubes, providing new information on turbulence modification due to density gradients and fluctuations. The success of experiments and model improvements depends on strong collaborations among modeling, experiment, and simulation.