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Two Dimensional Parametric Studies of Wake Vortex Interaction with the AtmosphereResults from parametric runs using two-dimensional TASS are presented. First, a set of experiments are presented that examine the sensitivity of the aircraft initiation height for an "in ground effect" case with weak crosswind. Interaction between the ground and the wake vortex produces an oscillatory rebound whose phase and amplitude are a function of the generation height. A second set of experiments are presented which examine the influence on crosswind shear. Shear layers, such as may be found between the nocturnal stable layer and the residual layer, can act to deflect vortices upward. Further investigation reveals that the second derivative of the crosswind can differentially reduce the descent speed of each member of a vortex pair, causing tilting of the vortex pair. If sufficiently large, the second derivative of crosswind can deflect the vortex pair upwards, with the sign of the second derivative determining which of the two vortices rises to a higher altitude. Linear shear, on the other hand, caused no change in the descent speed of the vortices; thus having no effect on the orientation of the vortices. Observed and model data from an actual case are presented in support of the conclusion regarding the influence of shear on rising vortices.
Document ID
19980073280
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Proctor, Fred
(NASA Langley Research Center Hampton, VA United States)
Date Acquired
August 18, 2013
Publication Date
November 1, 1997
Publication Information
Publication: Proceedings of the NASA First Wake Vortex Dynamic Spacing Workshop
Subject Category
Aerodynamics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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