Journal ArticleDOI
Flow Visualization in Turbulent Boundary Layers
Joseph A. Clar,Eric Markland +1 more
TLDR
In this article, visual observation of flow in a fully developed turbulent boundary layer along a two-dimensional channel has revealed the presence of systematic vortices both in the longitudinal and the transverse directions.Abstract:
Visual observation of flow in a fully developed turbulent boundary layer along a two-dimensional channel has revealed the presence of systematic vortices both in the longitudinal and the transverse directions. In some cases a pair of longitudinal vortices has been observed connected together by a transverse one in a horseshoe configuration. As the vortices are convected downstream they grow and decay, finally dispersing as new structures are formed. An attempt has been made to characterize these vortex structures in terms of the wall layer parameters.read more
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Journal ArticleDOI
Coherent Motions in the Turbulent Boundary Layer
TL;DR: In this paper, the role of coherent structures in the production and dissipation of turbulence in a boundary layer is characterized, summarizing the results of recent investigations, and diagrams and graphs are provided.
Journal ArticleDOI
The minimal flow unit in near-wall turbulence
Javier Jiménez,Parviz Moin +1 more
TL;DR: In this article, the authors performed direct numerical simulations of unsteady channel flow at low to moderate Reynolds numbers on computational boxes chosen small enough so that the flow consists of a doubly periodic array of identical structures.
Journal ArticleDOI
The autonomous cycle of near-wall turbulence
Javier Jiménez,Alfredo Pinelli +1 more
TL;DR: In this article, it is shown that a cycle exists which is local to the near-wall region and does not depend on the outer flow, and that the presence of the wall seems to be only necessary to maintain the mean shear.
Journal ArticleDOI
Computational Aerodynamics Development and Outlook
TL;DR: The field of computational fluid dynamics during recent years has developed sufficiently to initiate some changes in traditional methods of aerodynamic design, and numerical simulations offer the potential of mending many ills of wind-tunnel and turbomachinery experiments and of providing thereby important new technical capabilities for the aerospace industry.
Journal ArticleDOI
Issues in active flow control: theory, control, simulation, and experiment
TL;DR: In this article, the authors provide a perspective on the current status and future directions for active flow control technology with particular emphasis on oscillatory control, and make recommendations relevant to numerical complications on the route to design oscillatory flow-control systems.