Abstract
We are interested in the modeling of heat transfer in the turbulent boundary layer and at the wall : heat flux is a dimensioning parameter of the atmospheric re-entry vehicle at hypersonic regime. Up to now, the phenomena of transport of heat by turbulence were supposed to be governed by the same mechanisms as those for the momentum : it is the well-known Reynolds analogy. Thus, the models of turbulence generally take into account only the dynamic turbulent scales. The assumptions adopted in this case are restrictive (incompressible flow, flat plate...). In this thesis, we implement a thermal modeling of turbulence. The coupling between the averaged fields and the turbulent scales is done by the calculation of mu_t and lambda_t, these 2 quantities being evaluated using a k − epsilon / k_h − epsilon_h 4-equation model. A theoretical and practical study, based on an asymptotic analysis of the existing 4 equations low-Reynolds models in the literature, enabled us to develop new thermal models based on two-layer technique and wall functions. These models are built with new thermal turbulent scales. Thus, each phenomenon of transport has its own characteristic scales. Moreover, one systematic use for super- and hypersopnic flows around complex objects can be considered. These models were tested with a modified version of the computational fluid dynamic software NSC2KE and were confronted with experiments. They showed an improvement of the prediction of the heat transfer at the wall.