Publication Date:
1986-08-01
Description:
Several experiments have suggested that streamwise vortices, with their accompanying low-momentum streaks in a turbulent boundary layer have a characteristic spanwise wavelength of approximately λz+ =100. Here a mechanism is proposed which selects a comparable spanwise wavelength and produces counter-rotating streamwise vortices in a turbulent boundary layer. Examining the equations which describe the deviation of the velocity field from its time-average, it is found that a resonance (Benney & Gustavsson 1981), is associated with the mean-velocity profile. As an integral part of this resonance, there is a mean secondary flow which has a spanwise wavelength λ2+= 90 and whose velocities exhibit a streamwise vortex structure similar to those observed. © 1986, Cambridge University Press. All rights reserved.
Print ISSN:
0022-1120
Electronic ISSN:
1469-7645
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
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