Session Cb - Turbulence Simulation.
ORAL session, Sunday, November 23
302, Moscone Center
Recent results from a turbulent channel flow simulation using a vortex sheet and tube method will be described. The approach limits new vortex creation to just those arising from significant ejection events initiated by parent vortices. Together with the invocation of a hairpin removal algorithm and a technique for eliminating old highly stretched vortices, the number of vortex elements in a typical channel flow simulation achieves statistical equilibrium. Of particular interest is establishing that the algorithm represents the statistical and structural properties of physical turbulence. Clear evidence for a bona fide Reynolds shear stress is found in the computed averages, a persistent streaky structure in the near wall region, and the ability of the newly minted vortices to develop into substantial quasi-streamwise parent vortices over time. Toward the central region of the channel, the vortex elements display an increasingly anisotropic orientation. Preliminary results will also be presented from an application of the vortex method to the turbulent flow past a prolate spheroid.