Clercx, H.J.H. and Van Heijst, G.J.F. (1999) Some remarks on the role of boundary layers in decaying 2D turbulence in containers with no-slip walls. Il nuovo cimento C, 22 C (6). pp. 755-766. ISSN 1826-9885
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Abstract
Direct numerical simulations of decaying two-dimensional (2D) turbulence inside a square container with no-slip boundaries have been carried out for Reynolds numbers up to 2000. The role of the boundary layers during the decay process has been illustrated with ensemble-averaged results for the power law behaviour of several characteristic properties of the coherent vortices which emerge during the decay of 2D turbulence. The evolution of the vortex density, the average vortex radius, the enstrophy and the vorticity extrema have been computed. An algebraic decay regime has been observed during the initial turbulent decay stage. The computed decay exponents disagree, however, with the exponents from the classical scaling theory for 2D decaying turbulence on an unbounded domain. This is attributed to the presence of no-slip boundaries. Additionally, the temporal evolution of the average boundary-layer thickness has been studied by computing the ensemble-averaged viscous stress and normal vorticity gradient near the no-slip boundaries. These computations reveal that d(t)Ct 0.4 and that the average boundary-layer thickness is proportional with Re20.5.
| Item Type: | Article |
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| Additional Information: | Paper presented at the International Workshop on “Vortex Dynamics in Geophysical Flows”, Castro Marina (LE), Italy, 22-26 June 1998. |
| Uncontrolled Keywords: | Turbulence simulation and modeling ; vortex dynamics ; computational methods in fluid dynamics ; conference proceedings |
| Subjects: | 500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia |
| Depositing User: | Marina Spanti |
| Date Deposited: | 11 Oct 2019 14:52 |
| Last Modified: | 11 Oct 2019 14:52 |
| URI: | http://eprints.bice.rm.cnr.it/id/eprint/13664 |
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