Simulation of turbulence at very high Reynolds numbers is something that requires these mega computers. You can have a look at DOE's INCITE program awards to ge

Simulation of turbulence at very high Reynolds numbers is something that requires these mega computers. You can have a look at DOE's INCITE program awards to get an idea about these simulations: [0] http://www.doeleadershipcomputing.org/incite-awards/