Numerical simulation of mixing layer vortices
A simple model is proposed for the large spiral vortices observed in plane shear layers. An infinite, uniform vortex sheet is perturbed at one point and the resulting flow is studied numerically. A spiral structure appears that grows linearly for large values of time. The growth rates obtained agree with the observed values for the experimental layers within 25%.
KeywordsShear Layer Spreading Rate Spiral Structure Vortex Sheet Discrete Vortex
Unable to display preview. Download preview PDF.
- 1.Brown, G., Roshko, A.: On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64 (1974) 775–816.Google Scholar
- 2.Damms, S.M.; Küchemann, D.: On a vortex sheet model for the mixing between parallel streams. Royal Aircraft Establishment. Tech. Report 72139 (1972).Google Scholar
- 3.Acton, E.: The modelling of large eddies in a twodimensional shear layer. J. Fluid Mech. 76 (1976) 561–592.Google Scholar
- 4.Winant, D.C.; Browand, F.K.: Vortex Pairing: the mechanism of turbulent mixing-layer growth at moderate Reynolds number. J. Fluid Mech. 63 (1974) 237–255.Google Scholar
- 5.Birkhoff, G.: Helmholtz and Taylor instabilities. Proc. Symp. in App. Math. XIII (1962) 55. AMS: Providence R.I.Google Scholar
- 6.Powell, M.J.D.: A method for minimizing the sum of squares of non-linear functions calculating derivatives The Computer J. 7 (1965).Google Scholar
- 7.Batchelor, G.K.: An introduction to fluid dynamics. p. 528, Cambridge Univ. Press (1967).Google Scholar