scholarly journals Direct Numerical Simulation of Open Channel Turbulence Using Generalized Coordinate System and Upwind Difference Scheme

2000 ◽  
Vol 3 ◽  
pp. 763-774 ◽  
Author(s):  
Syunichiro HAYASHI ◽  
Terunori OHMOTO ◽  
Kouichi YAKITA ◽  
Ryuichi HIRAKAWA
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Difference Scheme ◽  
Coordinate System ◽  
Open Channel ◽  
Upwind Difference Scheme ◽  
Generalized Coordinate

scholarly journals Direct numerical simulation of intermittent turbulence under stably stratified conditions

2015 ◽  
Vol 2 (1) ◽  
pp. 179-241 ◽  
Author(s):  
P. He ◽  
S. Basu
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Open Channel ◽  
Temporal Evolution ◽  
Intermittent Turbulence ◽  
Bursting Events ◽  
Spatio Temporal ◽  
Channel Region ◽  
Laminar And Turbulent Flows

Abstract. In this paper, we simulate intermittent turbulence (also known as bursting events) in stably stratified open-channel flows using direct numerical simulation. Clear signatures of this intriguing phenomenon are observed for a range of stabilities. However, the spatio-temporal characteristics of intermittency are found to be strongly stability-dependent. In general, the bursting events are much more frequent near the bottom wall than in the upper-channel region. A steady coexistence of laminar and turbulent flows is detected at various horizontal planes in very stable cases. This spatially intermittent pattern is found to propagate downstream and strongly correlate with the temporal evolution of intermittency. Last, a long standing hypothesis by Blackadar, i.e., the strong connection between local stability and intermittent turbulence, is corroborated by this modeling study.

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