Coupled numerical simulation of flow and bed and suspended sediment transport over dunes based on the Immersed Boundary method

2014 ◽  
pp. 1053-1058
Author(s):  
G Leftheriotis ◽  
A Dimas
Keyword(s):  
Numerical Simulation ◽  
Sediment Transport ◽  
Suspended Sediment ◽  
Immersed Boundary Method ◽  
Immersed Boundary ◽  
Suspended Sediment Transport ◽  
Boundary Method

Coupled Simulation of Oscillatory Flow, Sediment Transport and Morphology Evolution of Ripples Based on the Immersed Boundary Method

2014 ◽  
Author(s):  
Georgios A. Leftheriotis ◽  
Athanassios A. Dimas
Keyword(s):  
Sediment Transport ◽  
Numerical Solution ◽  
Suspended Sediment ◽  
Immersed Boundary Method ◽  
Oscillatory Flow ◽  
Orbital Motion ◽  
Immersed Boundary ◽  
Morphology Evolution ◽  
Boundary Method ◽  
Motion Amplitude

In the present study, numerical simulations of oscillatory flow over a rippled bottom, coupled with bed and suspended sediment transport, as well as the resulting morphology evolution, are performed. The simulations are based on the numerical solution of the Navier-Stokes equations and the advection-diffusion equation for the suspended load, while empirical formulas are used for the bed load. The bed morphological evolution is obtained by the numerical solution of the conservation of sediment mass equation. A fractional time-step scheme is used for the temporal discretization, while finite differences are used for the spatial discretization on a Cartesian grid. The Immersed Boundary method is implemented for the imposition of fluid and sediment boundary conditions on the ripple surface. Two types of ripples are examined, i.e., ripples of parabolic shape with sharp crests and sinusoidal ripples, and cases of ripple length to orbital motion amplitude ratio of 1.6 and ripple height to orbital motion amplitude ratios of 0.16, 0.20 and 0.24, at Reynolds number equal to 5×103. The effect of ripple steepness and ripple shape on suspended sediment and ripple migration is discussed.

Simulation Flows Over Hemisphere at the Bed of an Open Channel by DNS and Immersed Boundary Method

2003 ◽  
Author(s):  
T. X. Dinh
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Immersed Boundary Method ◽  
Open Channel ◽  
Three Dimensional ◽  
Turbulent Channel Flow ◽  
Time Dependent ◽  
Immersed Boundary ◽  
Boundary Method ◽  
Finite Different Method

The immediate aim of this study is to check the accuracy of Kajishima’s method (one kind of immersed boundary method) for the direct numerical simulation (DNS) of turbulent channel flow over a complicated bed. In this paper, the simulation of three dimensional, time -dependent turbulent flows over a fixed hemisphere at the bed of an open channel is carried out. A finite different method (FDM) is applied with a staggered Cartesian mesh. The forces, the moments about the center of the hemisphere, and the distribution of pressure on the hemisphere in the plane of symmetry are calculated.

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