Near-Wall Turbulence in a Localized Puff in a Pipe
Progress in Turbulence VIII, pp. 15–20 (2019)
@inproceedings{yakhot-2019b,
author = {Yakhot, A. and Feldman, Y. and Moxey, D. and Sherwin, S. J. and Karniadakis, G. E.},
editor = {{\"O}rl{\"u}, Ramis and Talamelli, Alessandro and Peinke, Joachim and Oberlack, Martin},
title = {Near-Wall Turbulence in a Localized Puff in a Pipe},
booktitle = {Progress in Turbulence VIII},
year = {2019},
publisher = {Springer},
pages = {15--20},
abstract = {We have performed direct numerical simulations of a transitional flow in ai pipe for $Re_m=2250$ when turbulence manifests in the form of fleshes (puffs). From experiments and simulations, $Re_m approx 2250$ has been estimated as a threshold when the average speeds of upstream and downstream fronts of a puff are identical (Song et al. in J Fluid Mech 813:283--304, 2017, [1]). The flow regime upstream of its trailing edge and downstream of its leading edge is almost laminar. To collect the velocity data, at each time instance, we followed a turbulent puff by a three-dimensional moving window centered at the location of the maximum energy of the transverse (turbulent) motion. In the near-wall region, despite the low Reynolds number, the turbulence statistics, in particular, the distribution of turbulence intensities and Reynolds shear stress becomes similar to a fully-developed turbulent pipe flow.},
isbn = {978-3-030-22196-6},
doi = {10.1007/978-3-030-22196-6_3},
url = {https://davidmoxey.uk/assets/pubs/2019-nearwall-turb.pdf}
}
A shorter account of our direct numerical simulations of a turbulent puff travelling along a pipe at a Reynolds number of 2250, concentrating on the near-wall region. Despite the low Reynolds number, the turbulence intensities and Reynolds shear stress there come to resemble those of a fully developed turbulent pipe flow.
Abstract
We have performed direct numerical simulations of a transitional flow in ai pipe for Rem=2250 when turbulence manifests in the form of fleshes (puffs). From experiments and simulations, Rem approx 2250 has been estimated as a threshold when the average speeds of upstream and downstream fronts of a puff are identical (Song et al. in J Fluid Mech 813:283–304, 2017, [1]). The flow regime upstream of its trailing edge and downstream of its leading edge is almost laminar. To collect the velocity data, at each time instance, we followed a turbulent puff by a three-dimensional moving window centered at the location of the maximum energy of the transverse (turbulent) motion. In the near-wall region, despite the low Reynolds number, the turbulence statistics, in particular, the distribution of turbulence intensities and Reynolds shear stress becomes similar to a fully-developed turbulent pipe flow.