Dr. Antoine Llor
Senior Scientist at The French Alternative Energies and Atomic Energy Commission (CEA),
France

Entropic challenges in compressible multi-fluid flows and numerical schemes

Abstract
Some of the ongoing projects at the Commissariat à l’Energie Atomique in France require state of the art CFD, for instance to match the demands imposed by laser target implosions in inertial confinement fusion. These flows involve:

1. isentropic compression and expansion phases,
2. weak and strong shocks (entropy generating),
3. transport over long distances,
4. of many fluids with “ugly” equations of state,
5. undergoing mixing due to many hydrodynamic instabilities.

Of high concern is the robustness of the calculations which is primarily related to entropic consistency. It appears that this aspect is somewhat overlooked in the simulation of usual “gentler” or incompressible multifluid flows. Elementary principles will be reminded and some less obvious extensions investigated at CEA will be presented, which impact multifluid modeling and numerical schemes. In this context, isentropic tests such as Ransom’s faucet appear of critical importance.

Read more about CEA at: http://www.cea.fr/english/Pages/cea/the-cea-a-key-player-in-technological-research.aspx