scholarly journals Structure and modeling of the three dimensional boundary layer on a rotating disk. Final report

1996 ◽  
Author(s):  
J.K. Eaton
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Final Report ◽  
Dimensional Boundary

Instabilities of the von Kármán Boundary Layer

2015 ◽  
Vol 67 (3) ◽  
Author(s):  
R. J. Lingwood ◽  
P. Henrik Alfredsson
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Direct Numerical Simulations ◽  
Layer Model ◽  
Complex Flow ◽  
Von Karman ◽  
Dimensional Boundary ◽  
Flow Configurations ◽  
Von Kármán

Research on the von Kármán boundary layer extends back almost 100 years but remains a topic of active study, which continues to reveal new results; it is only now that fully nonlinear direct numerical simulations (DNS) have been conducted of the flow to compare with theoretical and experimental results. The von Kármán boundary layer, or rotating-disk boundary layer, provides, in some senses, a simple three-dimensional boundary-layer model with which to compare other more complex flow configurations but we will show that in fact the rotating-disk boundary layer itself exhibits a wealth of complex instability behaviors that are not yet fully understood.

Conversaziones 1955

1956 ◽  
Vol 12 (1) ◽  
pp. 9-20
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Rotating Disk ◽  
National Physical Laboratory ◽  
Turbulent Fluctuations ◽  
Research Activities ◽  
Physical Laboratory ◽  
Wide Range ◽  
Dimensional Boundary ◽  
Swept Wings

Conversaziones were held on 19 May and 28 June 1955. At the first there were thirty-six exhibits, covering a wide range of research activities. An acoustical demonstration of the instability of the laminar boundary layer on a rotating disk was given by Mr N. Gregory, Mr J. T. Stuart and Mr W. S. Walker, of the Aerodynamics Division, National Physical Laboratory. The rotating disk illustrates a phenomenon which also occurs in the flow over the swept wings of modern aircraft, the instability in the latter case being due to the growth of self-amplifying vortices in the three-dimensional boundary layer over the nose of the wing. By using a stethoscope the vibrations produced by the vortices and by the random turbulent fluctuations at the edge of the disk can clearly be heard.

Secondary instability in rotating-disk flow

1992 ◽  
Vol 242 ◽  
pp. 323-347 ◽  
Author(s):  
S. Balachandar ◽  
C. L. Streett ◽  
M. R. Malik
Keyword(s):  
Boundary Layer ◽  
Resonance Condition ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Secondary Instability ◽  
Exact Nature ◽  
Mean Flow ◽  
Large Growth ◽  
Dimensional Boundary ◽  
Tollmien Schlichting

Primary instability of the three-dimensional boundary layer on a rotating disk introduces periodic modulation of the mean flow in the form of stationary crossflow vortices. Here we study the stability of this modulated mean flow with respect to secondary disturbances. These secondary disturbances are found to have quite large growth rates compared to primary disturbances. Both fundamental and subharmonic resonance cases are considered and their corresponding results indicate that the growth rate and the frequency of the secondary instability are insensitive to the exact nature of the resonance condition. The threshold primary stationary crossflow vortex amplitude for secondary instability found in this three-dimensional incompressible boundary layer is significantly larger than that for a two-dimensional boundary layer which is subjected to Tollmien–Schlichting instability. The secondary instability results in a pair of travelling counter-rotating vortices, tilted up and oriented at an angle to the primary stationary crossflow vortices. The computed velocity signals and flow visualization, evaluated based on this secondary disturbance structure, are compared with experimental results.

Sign in / Sign up

Export Citation Format

Share Document