Interaction of surface waves with turbulence: direct numerical simulations of turbulent open-channel flow

1995 ◽  
Vol 286 ◽  
pp. 1-23 ◽  
Author(s):  
Vadim Borue ◽  
Steven A. Orszag ◽  
Ilya Staroselsky

We report direct numerical simulations of incompressible unsteady open-channel flow. Two mechanisms of turbulence production are considered: shear at the bottom and externally imposed stress at the free surface. We concentrate upon the effects of mutual interaction of small-amplitude gravity waves with in-depth turbulence and statistical properties of the near-free-surface region. Extensions of our approach can be used to study turbulent mixing in the upper ocean and wind–sea interaction, and to provide diagnostics of bulk turbulence.

2002 ◽  
Vol 46 ◽  
pp. 373-378 ◽  
Author(s):  
Akihiko NAKAYAMA ◽  
Satoshi YOKOJIMA

1996 ◽  
Vol 23 (6) ◽  
pp. 1272-1284 ◽  
Author(s):  
H. Chanson

Open channel flow situations with near-critical flow conditions are often characterized by the development of free-surface instabilities (i.e., undulations). The paper develops a review of several near-critical flow situations. Experimental results are compared with ideal-fluid flow calculations. The analysis is completed by a series of new experiments. The results indicate that, for Froude numbers slightly above unity, the free-surface characteristics are very similar. However, with increasing Froude numbers, distinctive flow patterns develop. Key words: open channel flow, critical flow conditions, free-surface undulations, flow instability, undular surge, undular broad-crested weir flow, culvert flow.


1996 ◽  
Vol 308 ◽  
pp. 15-29 ◽  
Author(s):  
Michael S. Longuet-Higgins

The surface of a turbulent, open-channel flow is often characterized by smooth areas of upwelling, each surrounded by a zone of downwelling marked by short steep waves. The dynamics of short waves on such a downwelling region are investigated and some laboratory experiments are proposed. Assuming that the horizontal strain rate Ω is locally constant, a simple expression is derived for the amplitude a of the short capillary–gravity waves, and hence also for the spectrum of the surface slopes.


Sign in / Sign up

Export Citation Format

Share Document