Type Ia supernovae are extremely bright stellar explosions whose light curves can be calibrated for use as standard candles in cosmology. Researchers simulating these explosions have a problem: the driver of the explosion, a flame less than 1cm wide, is so much smaller than the size of star that it can't be resolved in the simulations. So, full-star simulations of Type Ia supernovae must include a subgrid model that sets the flame speed below a certain scale. These subgrid models take into account the complex small-scale effects of the gravitationally-driven Rayleigh-Taylor (RT) instability, turbulence generated by the RT instability, and burning on the flame speed. Two main types of subgrid models are currently in use: turbulence-based models and RT-based models. The choice of subgrid model affects the full-star simulation outcome, yet there is no agreement about which models are most accurate. In this project, we simulate RT unstable flames using the spectral element code Nek5000 and compare measurements from these simulations to the predictions of different flame speed models. Currently, our main focus is on processes (like flame curvature) that can affect the local burning rate.
Our dance project, “Far From Equilibrium”, is an artistic exploration of turbulence. It will be performed on October 17th, 2015 at the Museum of Science and Industry in Chicago. Turbulence is in most places in the universe: in cream stirred into coffee, in the raging, swirling flames of forest fires on Earth, and even in massive explosions of energy from the surface of our Sun. However, this chaotic, complex, unstable twisting and stretching of fluid is mysterious, even to the scientists who study it. This work interprets and embodies the fundamental motions of turbulence, recombining them into new, intuitive forms: the turbulence of bodies mixing, the shear and glide of dancers in space, spirals and eddies of movement that appear and disappear without warning. “Far from Equilibrium” invites audience members to immerse themselves in the beauty of turbulence and reflect on its role in everyday life.