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Modelling the downstream development of a turbulent boundary layer following a step change of roughness

Li, Mogeng and de Silva, Charitha M. and Chung, Daniel and Pullin, Dale I. and Marusic, Ivan and Hutchins, Nicholas (2022) Modelling the downstream development of a turbulent boundary layer following a step change of roughness. Journal of Fluid Mechanics, 949 . Art. No. A7. ISSN 0022-1120. doi:10.1017/jfm.2022.731.

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In this study, we develop an analytical model to predict the turbulent boundary layer downstream of a step-change in the surface roughness where upstream flow conditions are given. We first revisit the classical model of Elliott (Trans. Am. Geophys. Union, vol. 39, 1958, pp. 1048–1054), who modelled the velocity distribution within and above the internal layer with a simple piecewise logarithmic profile, and evolved the velocity profile using the streamwise momentum equation. Elliott's model was originally developed for an atmospheric surface layer, and to make the model applicable to a spatially developing turbulent boundary layer with finite thickness, we propose a number of more physical refinements, including adding a wake function to the velocity profile, considering the growth of the entire boundary layer in the streamwise direction, and using a more realistic shear stress profile in the momentum equation. In particular, we implement the blending model (Li et al., J. Fluid Mech., vol. 923, 2021, p. A18) to account for the deviation of the mean flow within the internal layer from a canonical velocity profile based on the local wall condition. These refinements lead to improved agreement between the prediction and the measurement, especially in the vicinity of the rough-to-smooth change.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Li, Mogeng0000-0002-9875-6468
de Silva, Charitha M.0000-0001-9517-4318
Chung, Daniel0000-0003-3732-364X
Marusic, Ivan0000-0003-2700-8435
Hutchins, Nicholas0000-0003-1599-002X
Additional Information:Published online by Cambridge University Press: 23 September 2022. This research was supported under the Australian Research Council's Discovery and Linkage Projects funding scheme (projects DP160103619 and LP190101134).
Funding AgencyGrant Number
Australian Research CouncilDP160103619
Australian Research CouncilLP190101134
Subject Keywords:JFM classification: Turbulent Flows: Turbulent boundary layers
Record Number:CaltechAUTHORS:20221005-265369100.9
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117271
Deposited By: Melissa Ray
Deposited On:12 Oct 2022 18:07
Last Modified:12 Oct 2022 22:20

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