Доступ предоставлен для: Guest
TSFP DL Home Архив Исполнительный Комитет

VELOCITY STATISTICS AND STRUCTURE IN PIPE TURBULENCE DERIVED FROM A SIMPLE CRITICAL-LAYER MODEL

Ati S. Sharma
Department of Aeronautics Imperial College London, SW7 2AZ UK; Engineering and the Environment University of Southampton Highfield, Southampton, SO17 1BJ, UK

Beverley J. McKeon
Department of Aeronautics, Imperial College London, SW7 2AZ, UK; Graduate Aerospace Laboratories California Institute of Technology Pasadena, CA 91125, USA

Аннотация

We describe the development of a simple forcing-response analysis of the Navier-Stokes equations that predicts important structural and scaling features of wall turbulence. In particular, we propose an economical explanation for the meandering appearance of very large scale motions observed in turbulent pipe flow, and likewise demonstrate that hairpin vortices are predicted, using a simple linear superposition of modes derived from the model. The computationally cheap approach explains and predicts vortical structures and velocity statistics of turbulent flows that have previously been identified only in experiments or by direct numerical simulation. This new capability has clear implications for modeling, simulation and control of a ubiquitous class of wall flows.