Vortex Flows and Related Numerical Methods II
ESAIM: Proceedings,
Vol. 1, 1996, pp. 15-31
A Vortex Method for Wall Bounded Turbulent Flows
Peter S. Bernard
Department of Mechanical Engineering
University of Maryland
College Park, MD 20742, USA
Abstract
Turbulent flow in a channel is simulated using a vortex method. Smoothed
vortex sheets cover the near wall region while the vorticity in the
remainder of the flow is contained in convecting and stretching vortex
filaments. The sheet elements are convected and regridded at each time
step thus enabling evaluation of their wall-normal viscous diffusion and
vortex stretching using finite differences. New filaments are created
during significant ejection events initiated by parent vortices. Chorin's
hairpin removal algorithm is used as a physically based subgrid model to
limit the range of resolved scales. Calculations on the order of 2000 time
steps have been completed thus far. From a perturbed state, the numerical
solution develops toward a self-sustained turbulent flow. An initial
explosive growth in the number of new vortex structures occurs as the flow
compensates for the absence of sufficient spanwise vorticity in the initial
conditions. Vortex production is self-limiting, however, and the flow
subsequently relaxes toward a quasi-equilibrium in which new vortex
filament creation occurs at only a small number of spatially intermittent
locations. Preliminary statistics taken from the ongoing simulations
suggest that the computational field is approaching the correct physical
state.
Vortex Flows and Related
Numerical Methods II
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