Modeling of low-cement extruded curb of concrete-faced rockfill dam

2011 ◽  
Vol 48 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Ga Zhang ◽  
Jian-Min Zhang
Keyword(s):  
Numerical Simulation ◽  
Damage Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Direct Simulation ◽  
Construction Technique ◽  
Displacement Analysis ◽  
Rockfill Dam ◽  
The Face ◽  
Cushion Layer

As the key structure of a practical construction technique, the low-cement extruded curb has been widely used in recent concrete-faced rockfill dams (CFRDs). The extruded curb exhibits significant interactions with the neighboring gravels and with the face slab. These interactions were investigated using element tests, and a new model was proposed. This model is composed of three parts: (i) the equivalent slab that is described using an ideal elastoplasticity model, (ii) the equivalent interface between the curb and the gravel cushion layer that is described using an elastoplasticity damage model, and (iii) the interface between the curb and the face slab that is described using a modified ideal elastoplasticity model. This model was verified via a two-dimensional numerical simulation of an ideal CFRD to capture the main behavior of the extruded curb with interactions between the extruded curb and the neighboring soil – face slab, employing a significantly smaller number of elements and a shorter calculation than direct simulation. The model was used to perform a three-dimensional stress–displacement analysis of the Bakun CFRD (205 m in height), and the results showed that the extruded curb causes a change in the stress of the face slab.

Wake Flow of Single and Multiple Yawed Cylinders

2004 ◽  
Vol 126 (5) ◽  
pp. 861-870 ◽  
Author(s):  
A. Thakur ◽  
X. Liu ◽  
J. S. Marshall
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Wake Flow ◽  
Upstream Region ◽  
Two Dimensional ◽  
Cylinder Wake ◽  
Dimensional Approximation ◽  
The Face ◽  
Drag And Lift

An experimental and computational study is performed of the wake flow behind a single yawed cylinder and a pair of parallel yawed cylinders placed in tandem. The experiments are performed for a yawed cylinder and a pair of yawed cylinders towed in a tank. Laser-induced fluorescence is used for flow visualization and particle-image velocimetry is used for quantitative velocity and vorticity measurement. Computations are performed using a second-order accurate block-structured finite-volume method with periodic boundary conditions along the cylinder axis. Results are applied to assess the applicability of a quasi-two-dimensional approximation, which assumes that the flow field is the same for any slice of the flow over the cylinder cross section. For a single cylinder, it is found that the cylinder wake vortices approach a quasi-two-dimensional state away from the cylinder upstream end for all cases examined (in which the cylinder yaw angle covers the range 0⩽ϕ⩽60°). Within the upstream region, the vortex orientation is found to be influenced by the tank side-wall boundary condition relative to the cylinder. For the case of two parallel yawed cylinders, vortices shed from the upstream cylinder are found to remain nearly quasi-two-dimensional as they are advected back and reach within about a cylinder diameter from the face of the downstream cylinder. As the vortices advect closer to the cylinder, the vortex cores become highly deformed and wrap around the downstream cylinder face. Three-dimensional perturbations of the upstream vortices are amplified as the vortices impact upon the downstream cylinder, such that during the final stages of vortex impact the quasi-two-dimensional nature of the flow breaks down and the vorticity field for the impacting vortices acquire significant three-dimensional perturbations. Quasi-two-dimensional and fully three-dimensional computational results are compared to assess the accuracy of the quasi-two-dimensional approximation in prediction of drag and lift coefficients of the cylinders.

scholarly journals Modelling of the processes of impact of a projectile with elements of individual defence

2019 ◽  
Vol 221 ◽  
pp. 01021
Author(s):  
Aleksandr Kraus ◽  
Evgeny Kraus ◽  
Ivan Shabalin
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Heterogeneous Media ◽  
Three Dimensional ◽  
Stationary Problem ◽  
Heterogeneous Structure ◽  
Plate Steel ◽  
Two Dimensional ◽  
Human Bones ◽  
Armor Plate

A two-dimensional and three-dimensional non-stationary problem of the interaction of a homogeneous impactor and a heterogeneous structure made of steel and ceramics and placed in a Kevlar pocket is considered. The model of the human body is a plate of gelatine with cylindrical inserts-imitators of human bones. The results of numerical simulation using different approaches for describing heterogeneous media are compared. On the basis of direct numerical simulation, it is shown that the gradient armor plate (steel + B4C) has the best weight and size parameters.

Symbolic computation study on exact solutions to a generalized (3+1)-dimensional Kadomtsev-Petviashvili-type equation

2020 ◽  
pp. 2150116
Author(s):  
Cheng-Cheng Zhou ◽  
Xing Lü ◽  
Hai-Tao Xu
Keyword(s):  
Numerical Simulation ◽  
Exact Solutions ◽  
Prime Number ◽  
Symbolic Computation ◽  
Three Dimensional ◽  
Type Equation ◽  
Two Dimensional ◽  
Type Solution ◽  
Bilinear Operators ◽  
Number Formula

Based on the prime number [Formula: see text], a generalized (3+1)-dimensional Kadomtsev-Petviashvili (KP)-type equation is proposed, where the bilinear operators are redefined through introducing some prime number. Computerized symbolic computation provides a powerful tool to solve the generalized (3+1)-dimensional KP-type equation, and some exact solutions are obtained including lump-type solution and interaction solution. With numerical simulation, three-dimensional plots, density plots, and two-dimensional curves are given for particular choices of the involved parameters in the solutions to show the evolutionary characteristics.

scholarly journals Direct Numerical Simulation of Flow around a Circular Cylinder Controlled Using Plasma Actuators

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Taichi Igarashi ◽  
Hiroshi Naito ◽  
Koji Fukagata
Keyword(s):  
Numerical Simulation ◽  
Circular Cylinder ◽  
Direct Numerical Simulation ◽  
Drag Reduction ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Plasma Actuators ◽  
Two Dimensional ◽  
Freestream Velocity ◽  
The Mean

Flow around a circular cylinder controlled using plasma actuators is investigated by means of direct numerical simulation (DNS). The Reynolds number based on the freestream velocity and the cylinder diameter is set atReD=1000. The plasma actuators are placed at±90° from the front stagnation point. Two types of forcing, that is, two-dimensional forcing and three-dimensional forcing, are examined and the effects of the forcing amplitude and the arrangement of plasma actuators are studied. The simulation results suggest that the two-dimensional forcing is primarily effective in drag reduction. When the forcing amplitude is higher, the mean drag and the lift fluctuations are suppressed more significantly. In contrast, the three-dimensional forcing is found to be quite effective in reduction of the lift fluctuations too. This is mainly due to a desynchronization of vortex shedding. Although the drag reduction rate of the three-dimensional forcing is slightly lower than that of the two-dimensional forcing, considering the power required for the forcing, the three-dimensional forcing is about twice more efficient.

scholarly journals Numerical simulation of mixing by Rayleigh–Taylor and Richtmyer–Meshkov instabilities

1994 ◽  
Vol 12 (4) ◽  
pp. 725-750 ◽  
Author(s):  
D.L. Youngs
Keyword(s):  
Numerical Simulation ◽  
Turbulence Model ◽  
Turbulent Mixing ◽  
Inertial Confinement Fusion ◽  
Three Dimensional ◽  
Small Scale ◽  
Inertial Confinement ◽  
Two Dimensional ◽  
Confinement Fusion ◽  
Icf Target

Rayleigh-Taylor (RT) and Richtmyer–Meshkov (RM) instabilities at the pusher–fuel interface in inertial confinement fusion (ICF) targets may significantly degrade thermonuclear burn. Present-day supercomputers may be used to understand the fundamental instability mechanisms and to model the effect of the ensuing mixing on the performance of the ICF target. Direct three-dimensional numerical simulation is used to investigate turbulent mixing due to RT and RM instability in simple situations. A two-dimensional turbulence model is used to assess the effect of small-scale turbulent mixing in the axisymmetric implosion of an idealized ICF target.

Small-scale structure of two-dimensional magnetohydrodynamic turbulence

1979 ◽  
Vol 90 (1) ◽  
pp. 129-143 ◽  
Author(s):  
Steven A. Orszag ◽  
Cha-Mei Tang
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Three Dimensional ◽  
Scale Structure ◽  
Magnetohydrodynamic Flow ◽  
Small Scale ◽  
Two Dimensional ◽  
Magnetohydrodynamic Turbulence ◽  
Hydrodynamic Turbulence ◽  
Small Scale Structure

The formation of singularities in two-dimensional magnetohydrodynamic flow is investigated by direct numerical simulation. It is shown that two-dimensional magnetohydrodynamic turbulence is not as singular as three-dimensional hydrodynamic turbulence (in the sense that it has a less highly excited small-scale structure) but that it is more singular than two-dimensional hydrodynamic turbulence.

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