ISSN:
1089-7666
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The local topology evolution of a high-symmetry, high resolution (effective maximum resolution of 10243 grid points, maximum wave number of 341) incompressible flow simulation having a Reynolds number (=1/ν) of 1000 is investigated. The Q–R invariants of the velocity gradient tensor Aij, the enstrophy, ΩijΩij and the mean-square strain rate SijSij are computed at an interval when the local maximum vorticity increases drastically. All the analysis of the computations are done on the z=0 plane, where the maximum vorticity and strain are located during the evolution. In the Q–R plane, most of the collocation points evolve towards the lower right corner, a region where strain dominates over vorticity. The pressure Hessian tensor components are computed in the 0 planes. Points with very large strain and no vorticity, which are located along the boundaries separating oppositely signed vortices, are found to have a diagonal pressure Hessian tensor. It is discussed how such a Hessian tensor form can result in a singularity formation in strain (and Q invariant). Relevance of the results to turbulence is discussed. Results are compared to the predictions of a singular model by Léorat (Ph.D. thesis, Université de Paris VII, pp. 125–129, 1975), Vieillefosse [J. Phys. 43, 837 (1982)], and Cantwell [Phys. Fluids A 5, 2008 (1992)]. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.868487
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