supercomputer at the Department of Energy’s Oak Ridge National Laboratory revealed new insights into the role of turbulence in mixing fluids and could open new possibilities for projecting climate change and studying fluid dynamics., used Summit to model the dynamics of a roughly 10-meter section of ocean. That study generated one of the most detailed simulations to date of howdisperses heat through seawater under realistic conditions.
“In this case, you have colder fluid sitting on the ocean floor and warmer fluid above,” Couchman said. “One of the big uncertainties forand other such applications arises from a lack of understanding of how heat mixes across these layers. The surface waters are being heated from above by the sun, but how does that heat get dispersed? It turns out that turbulent processes play a key role, which is what we’re now trying to better understand.
The computational power of Summit allowed the team to fully resolve the ocean turbulence at realistic ratios for the first time, providing new insight into the ocean’s turbulent dynamics. “One typical approach simplifies the results by averaging measurements across the entire domain,” Couchman said. “But that approach smears out the important finer details and just gives you a cloudy picture of what’s happening. We wanted to take this section of water and follow the turbulence from the initial burst all the way until the motion dies out, analyzing all relevant scales.
“Let’s go back to the example of the coffee and cream,” de Bruyn Kops said. “A basic assumption of turbulence theory has been the cold cream and the hot coffee should mix at the same rate, as you stir and the coffee goes from black to brown. But we’re finding from these simulations that’s not the case. The heat’s mixing at a slower rate than the momentum from the turbulence. That’s a whole new avenue to explore.