Large-eddy simulation of transitional channel flow

✍ Scribed by Ugo Piomelli; Thomas A. Zang

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 445 KB
• Volume: 65
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/0010-4655(91)90175-k

✦ Synopsis

A large-eddy simulation (LES) of transition in plane channel flow has been carried out. The LES results have been compared with those of a fine direct numerical simulation (DNS), and with those of a coarse DNS that uses the same mesh as the LES, but no residual stress model. While at the early stages of transition LES and coarse DNS give the same results, the presence of the residual stress model was found to be necessary to predict accurately mean velocity and Reynolds stress profiles during the late stages of transition (after the second spike stage). The evolution of single Fourier modes is also predicted more accurately by the LES than by the coarse DNS. As small scales are generated, the dissipative character of the residual stress causes it to reproduce correctly the energy cascade; as transition progresses, then, and the flow approaches its fully developed turbulent state, the subgrid scales tend towards equilibrium and the model becomes more accurate.