Asymptotic Modelling of Fluid Flow Phenomena

for the fluctuations around the means but rather fluctuations, and appearing in the following incompressible system of equations: on any wall; at initial time, and are assumed known. This contribution arose from discussion with J. P. Guiraud on attempts to push forward our last co-signed paper (1986) and the main idea is to put a stochastic structure on fluctuations and to identify the large eddies with a part of the probability space. The Reynolds stresses are derived from a kind of Monte-Carlo process on equations for fluctuations. Those are themselves modelled against a technique, using the Guiraud and Zeytounian (1986). The scheme consists in a set of like equations, considered as random, because they mimic the large eddy fluctuations. The Reynolds stresses are got from stochastic averaging over a family of their solutions. Asymptotics underlies the scheme, but in a rather loose hidden way. We explain this in relation with homogenizati- localization processes (described within the §3. 4 ofChapter 3). Ofcourse the mathematical well posedness of the scheme is not known and the numerics would be formidable! Whether this attempt will inspire researchers in the field of highly complex turbulent flows is not foreseeable and we have hope that the idea will prove useful.

Preface and Acknowledgments. 1. Introductory Comments and Summary. Part I: Setting the Scene. 2. Newtonian Fluid Flow: Equations and Conditions. 3. Some Basic Aspects of Asymptotic Analysis and Modelling. 4. Useful Limiting Forms of the NS-F Equations. Part II: Main Asymptotic Models. 5. The Navier-Fourier Viscous Incompressible Model. 6. The Inviscid/Nonviscous Euler Model and Some Hydro-Aerodynamics Problems. 7. Boundary-Layer Models for High-Reynolds Numbers. 8. Some Models of Nonlinear Acoustics. 9. Low-Reynolds Numbers asymptotics. Part III: Three Specific Asymptotic Models. 10. Asymptotic Modelling of Thermal Convection and Interfacial Phenomena. 11. Meteo-Fluid-Dynamics Models. 12. Singular Coupling and the Triple-Deck Model. References.