  The French collaborative Trio4CLF project aims to understand and control the
cryogenic cooling of amplifiers for high power (~1 PetaWatt) and high
repetition rate (1-10 Hertz) lasers. In such amplifiers, the fluid evacuates
the thermal power absorbed by the solid amplifying plates. A precise knowledge
of the heat exchange and thus of the turbulent fluid flow in the amplifier is
requested to evaluate its impact on the laser beam quality. As a first step, a
Large Eddy Simulation is carried out in air without heating to study the
development of the turbulent flow. The CFD code used is TrioCFD, a code
developed by the CEA. For validation purpose, the simulation is carried out in
the experimental setup configuration: a closed-loop wind tunnel called TRANSAT.
Two horizontal plates, separated by 0.05 m, are put in the airflow to represent
the amplifier plates. Turbulent boundary layers develop from the plates edges.
Numerically, the entrance flow is a homogeneous planar flow with a constant
velocity at 10 m/s. The results of this Large Eddy Simulation are presented in
this paper as a study of the development of the turbulent boundary layers
created by the plates.
