64th Annual Meeting of the APS Division of Fluid Dynamics
Volume 56, Number 18
Sunday–Tuesday, November 20–22, 2011;
Baltimore, Maryland
Session K27: Invited Session: Experimental Manipulation of Wall-Bounded Turbulence
2:40 PM–3:15 PM,
Monday, November 21, 2011
Room: Ballroom I-II
Chair: Alexander Smits, Princeton University
Abstract ID: BAPS.2011.DFD.K27.1
Abstract: K27.00001 : Experimental Manipulation of Wall-Bounded Turbulence
2:40 PM–3:15 PM
Preview Abstract
Author:
Beverley McKeon
(California Institute of Technology)
The potential gains in efficiency across a range of
applications associated with successful control of wall-
bounded turbulence are well-known, as are the many challenges
this interdisciplinary problem encompasses. Further, while
there have been recent developments in fundamental wall
turbulence research, including description of the
characteristics of coherent structures (e.g. Adrian, 2007) and
the very large scale motions (e.g. Mathis \textit{et al},
2009), many fundamental questions remain, in particular with
respect to scaling behavior as the Reynolds number is increased
to practically important values. Progress can be made in both
understanding the response of canonical flows to forcing at the
wall and isolating mechanisms important to the unperturbed
flows using open-loop forcing. To this end, recent work has
shown how small amplitude perturbations to surface roughness
designed to isolate individual spatial and temporal scales
(a ``dynamic roughness'') can be used to manipulate the
characteristics of wall turbulence. This talk will describe the
experimental manipulation of a turbulent boundary layer using
dynamic roughness and the connection to the spatio-temporal
(spectral) information traditionally reported in turbulence
studies. The development of tools from earlier work on
directional amplification of the Navier-Stokes operator into
simple models by which to interpret the coupling between the
wall motion and the flow will be described, and some examples
of the understanding of structure and Reynolds number trends in
the canonical (unperturbed) flow that emerge from the perturbed
case will be given.
The contribution of students and collaborators, in particular
Dr. Ati Sharma (University of Sheffield, U.K.) and Ian Jacobi
(Caltech), to this work and the support of AFOSR (grant FA
\#9550-09-1-0701, program manager John Schmisseur) are
gratefully acknowledged.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.DFD.K27.1