Turbulent flow over Topography with Applications to Sand-Wave Development

1986 ◽  
pp. 435-461
Author(s):  
K. J. Richards
Keyword(s):  
Turbulent Flow ◽  
Sand Wave ◽  
Flow Over Topography ◽  
Wave Development

scholarly journals Study on hydraulic resistance of erodible bed at the Chiyoda experimental flume

2014 ◽  
Vol 39 ◽  
pp. 81-87
Author(s):  
T. Kakinuma ◽  
T. Inoue ◽  
R. Akahori ◽  
A. Takeda
Keyword(s):  
Large Scale ◽  
Flow Distribution ◽  
Longitudinal Survey ◽  
Sand Wave ◽  
Vertical Flow ◽  
Sand Waves ◽  
Wave Development ◽  
Logarithmic Distribution ◽  
Steady Flow Condition ◽  
Experimental Flume

Abstract. The authors made erodible bed experiments under steady flow condition at the Chiyoda Experimental Flume, a large-scale facility constructed on the floodplain of the Tokachi River, and observed sand waves on the bed of the flume. In this study, the characteristics of the sand waves are examined along the longitudinal survey lines and confirmed to be dunes. Next, the authors estimated Manning's roughness coefficients from the observed hydraulic values and assumed that the rise of the coefficients attributed to the sand wave development. Finally, vertical flow distribution on the sand waves are examined, and observed velocity distribution on the crest of waves found to be explained by the logarithmic distribution theory.

Large-Scale Stationary and Turbulent Flow over Topography

1984 ◽  
Vol 41 (22) ◽  
pp. 3255-3271 ◽  
Author(s):  
Geoffrey K. Vallis ◽  
John O. Roads
Keyword(s):  
Turbulent Flow ◽  
Large Scale ◽  
Flow Over Topography

Numerical simulation of sand waves in a turbulent open channel flow

2014 ◽  
Vol 753 ◽  
pp. 150-216 ◽  
Author(s):  
Ali Khosronejad ◽  
Fotis Sotiropoulos
Keyword(s):  
Turbulent Flow ◽  
Numerical Simulations ◽  
Coherent Structures ◽  
Open Channel ◽  
Good Accuracy ◽  
Spectral Gap ◽  
Three Dimensional ◽  
Sand Wave ◽  
Sand Waves ◽  
Mobile Bed

AbstractWe develop a coupled hydro-morphodynamic numerical model for carrying out large-eddy simulation of stratified, turbulent flow over a mobile sand bed. The method is based on the curvilinear immersed boundary approach of Khosronejad et al. (Adv. Water Resour., vol. 34, 2011, pp. 829–843). We apply this method to simulate sand wave initiation, growth and evolution in a mobile bed laboratory open channel, which was studied experimentally by Venditti & Church (J. Geophys. Res., vol. 110, 2005, F01009). We show that all the major characteristics of the computed sand waves, from the early cross-hatch and chevron patterns to fully grown three-dimensional bedforms, are in good agreement with the experimental data both qualitatively and quantitatively. Our simulations capture the measured temporal evolution of sand wave amplitude, wavelength and celerity with good accuracy and also yield three-dimensional topologies that are strikingly similar to what was observed in the laboratory. We show that near-bed sweeps are responsible for initiating the instability of the initially flat sand bed. Stratification effects, which arise due to increased concentration of suspended sediment in the flow, also become important at later stages of the bed evolution and need to be taken into account for accurate simulations. As bedforms grow in amplitude and wavelength, they give rise to energetic coherent structures in the form of horseshoe vortices, which transport low-momentum near-bed fluid and suspended sediment away from the bed, giving rise to characteristic ‘boil’ events at the water surface. Flow separation off the bedform crestlines is shown to trap sediment in the lee side of the crestlines, which, coupled with sediment erosion from the accelerating flow over the stoss side, provides the mechanism for continuous bedform migration and crestline rearrangement. The statistical and spectral properties of the computed sand waves are calculated and shown to be similar to what has been observed in nature and previous numerical simulations. Furthermore, and in agreement with recent experimental findings (Singh et al., Water Resour. Res., vol. 46, 2010, pp. 1–10), the spectra of the resolved velocity fluctuations above the bed exhibit a distinct spectral gap whose width increases with distance from the bed. The spectral gap delineates the spectrum of turbulence from the low-frequency range associated with very slowly evolving, albeit energetic, coherent structures induced by the migrating sand waves. Overall the numerical simulations reproduce the laboratory observations with good accuracy and elucidate the physical phenomena governing the interaction between the turbulent flow and the developing mobile bed.

An Introduction to Turbulent Flow

2000 ◽  
Author(s):  
Jean Mathieu ◽  
Julian Scott
Keyword(s):  
Turbulent Flow

Modal Analysis of Turbulent Flow near an Inclined Bank–Longitudinal Structure Junction

2021 ◽  
Vol 147 (3) ◽  
pp. 04020100
Author(s):  
Nasser Heydari ◽  
Panayiotis Diplas ◽  
J. Nathan Kutz ◽  
Soheil Sadeghi Eshkevari
Keyword(s):  
Turbulent Flow ◽  
Modal Analysis ◽  
Longitudinal Structure

Numerical simulation of subsonic turbulent flow of oscillating NACA 0015 airfoi

2018 ◽  
Vol 2 ◽  
pp. 133-145
Author(s):  
D.O. Redchyts ◽  
◽  
S.V. Moiseenko ◽  
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flow ◽  
Naca 0015

LIMITATIONS OF THE STOCHASTIC APPROACH IN TWO-PHASE TURBULENT FLOW CALCULATIONS

1996 ◽  
Vol 6 (2) ◽  
pp. 211-225 ◽  
Author(s):  
Keh-Chin Chang ◽  
Wen-Jing Wu ◽  
Muh-Rong Wang
Keyword(s):  
Turbulent Flow ◽  
Stochastic Approach ◽  
Two Phase
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