Predictions of canonical wall bounded turbulent flows via a modified $k-\omega$ equation
Abstract
A major challenge in computation of engineering flows is to derive and improve turbulence models built on turbulence physics. Here, we present a physics-based modified equation for canonical wall bounded turbulent flows (boundary layer, channel and pipe), predicting both mean velocity profile (MVP) and streamwise mean kinetic energy profile (SMKP) with high accuracy over a wide range of Reynolds number (). The result builds on a multi-layer quantification of wall flows, which allows a significant modification of the equation. Three innovations are introduced: First, an adjustment of the Karman constant to 0.45 is set for the overlap region with a logarithmic MVP. Second, a wake parameter models the turbulent transport near the centerline. Third, an anomalous dissipation factor represents the effect of a meso layer in the overlap region. Then, a highly accurate (above 99\%) prediction of MVPs is obtained in Princeton pipes, improving the original model prediction by up to 10\%. Moreover, the entire SMKP, including the newly observed outer peak, is predicted. With a slight change of the wake parameter, the model also yields accurate predictions for channels and boundary layers.
Keywords
Cite
@article{arxiv.1606.01415,
title = {Predictions of canonical wall bounded turbulent flows via a modified $k-\omega$ equation},
author = {Xi Chen and Fazle Hussain and Zhen-Su She},
journal= {arXiv preprint arXiv:1606.01415},
year = {2016}
}
Comments
22 pages, 14 figures