, although it increases with increasing turbulence
integral length scale. The vortex lifespan is controlled primarily by
and decreases with increasing ,
whereas the effect of integral scale
of turbulence on vortex lifespan is of minor importance.
The lifespan is estimated to be about 40% larger than
Crow and Bate's predicted value (Crow, S. C. and Bate, E. R., "Lifespan of
Trailing Vortices on a Turbulent Atmosphere," Journal of Aircraft,
Vol. 13, No. 7, 1976, pp. 476-482) but in agreement with Sarpkaya's recent
modification (Sarpkaya, T., "Decay of Wake Vortices of Large Aircraft,"
AIAA Journal, Vol. 36, No. 9, 1998, pp. 1671-1679) to Crow and Bate's
theory. This larger lifespan is also supported by data from water tank
experiments and direct numerical simulations.
There appears to be a possibility that the scatter
in vortex lifespans due to ambient turbulence alone decreases with
increasing Reynolds number, whereas larger scatter of lifespans in flight tests
may result from other factors such as stratification, wind shear,
and inhomogeneous ambient turbulence.
Member publication : 2000
Member publication
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