The effect of thixotropy on dam-break flow: a numerical study by smoothed particle hydrodynamics

<p>Overtopping dam-break flow has great harm to the earthen embankments due to the hydraulic erosion. Some researchers have carried out relevant model experiments, but it is difficult to achieve the experimental conditions for the actual situation. The common numerical simulation is to express the scouring process through the empirical relationship, which obviously could not reflect the real scouring process. In this paper, a new overtopping erosion model using Smoothed Particle Hydrodynamics (SPH) is proposed. When the shear stress on the sediment SPH particle exceeds the critical stress, the erosion process begins. Then, when a sediment SPH particle is completely eroded, it will begin to move and is described as a non-Newtonian fluid. The un-incipient sediment particles are treated as boundary. This model is well validated with plane dike-breach experiment, and has also achieved a good agreement with erodible bed dam-break experiment.</p>

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A Numerical Study of Fluid Flow in a Vertical Slot Fishway with the Smoothed Particle Hydrodynamics Method

Water ◽

10.3390/w11091928 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1928 ◽

Cited By ~ 3

Author(s):

Gorazd Novak ◽

Angelantonio Tafuni ◽

José M. Domínguez ◽

Matjaž Četina ◽

Dušan Žagar

Keyword(s):

Smoothed Particle Hydrodynamics ◽

Numerical Study ◽

Free Surface Flows ◽

Open Boundary ◽

Doppler Velocity ◽

Vertical Slot ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Smoothed Particle Hydrodynamics Method ◽

Vertical Slot Fishway

Fishways have a great ecological importance as they help mitigate the interruptions of fish migration routes. In the present work, the novel DualSPHysics v4.4 solver, based on the smoothed particle hydrodynamics method (SPH), has been applied to perform three-dimensional (3-D) simulations of water flow in a vertical slot fishway (VSF). The model has been successfully calibrated against published field data of flow velocities that were measured with acoustic Doppler velocity probes. A state-of-the-art algorithm for the treatment of open boundary conditions using buffer layers has been applied to accurately reproduce discharges, water elevations, and average velocity profiles (longitudinal and transverse velocities) within the observed pool of the VSF. Results herein indicate that DualSPHysics can be an accurate tool for modeling turbulent subcritical free surface flows similar to those that occur in VSF. A novel relation between the number of fluid particles and the artificial viscosity coefficient has been formulated with a simple logarithmic fit.

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Numerical study of rainstorm influence on parachute airdropping based on the smoothed particle hydrodynamics/arbitrary Lagrangian–Eulerian coupling method

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925020915616 ◽

2020 ◽

Vol 15 ◽

pp. 155892502091561

Author(s):

Linbo Yan ◽

Zhengkai Sun ◽

Han Cheng

Keyword(s):

Smoothed Particle Hydrodynamics ◽

Wind Field ◽

Numerical Study ◽

Great Influence ◽

Coupling Method ◽

Influential Factor ◽

Arbitrary Lagrangian Eulerian ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

And Performance

In order to study the influence of rainstorm on parachute dropping, the smoothed particle hydrodynamics/arbitrary Lagrangian–Eulerian coupling method is proposed. Finite elements are used to describe the continuous material such as fabric and air flow field, and the smoothed particle hydrodynamics particles are used to describe the discrete raindrops. The coupling between different fluid and structure is realized by penalty function. In order to distinguish the most influential factor of rainstorm environment on parachute, the effects of raindrop field and wind field in rainstorm are studied, respectively. It could be found that the raindrop fields with different droplet sizes have little effect on the parachute’s shape, opening shock, and performance according to the comparative analysis, while the vertical wind field has a great influence on parachute’s deceleration performance. The wind field, not the raindrop field, is the most important factor affecting the parachute’s deceleration performance. The method and conclusions in this article could provide some references for parachute design.

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