Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session M21: Boundary Layer Flows over Rough Surfaces II
8:00 AM–10:10 AM,
Tuesday, November 20, 2018
Georgia World Congress Center Room: B309
Chair: Jean-Pierre Hickey, University of Waterloo
Abstract ID: BAPS.2018.DFD.M21.6
Abstract: M21.00006 : Modeling Nonlinear Interactions in a Rough-Wall Turbulent Boundary Layer*
9:05 AM–9:18 AM
We model a wall with small-amplitude sinusoidal roughness as a small perturbation to a turbulent boundary layer. By altering the linearized boundary condition of the Navier-Stokes equations for a single spatial wavenumber, the roughness introduces a stationary, periodic velocity perturbation that interacts non-linearly with pairs of triadically-consistent convecting modes which make up the fluctuating velocity field. This study models these processes in a low-order fashion by approximating the stationary and convecting modes as the most-amplified resolvent modes for a given wavenumber and frequency. The model’s predictions are found to qualitatively reproduce the effects of two distinct sinusoidal roughnesses on the power spectrum of a turbulent boundary layer. Implications to more general roughness are discussed.
*The support of ONR under grant N000141310739 is gratefully acknowledged.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DFD.M21.6
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