Numerical Simulation of Wave Transformation Over Deep-Sea Platform Reef Using SPH Method

Author(s):  
Xiang Zhang ◽  
Bing Ren ◽  
Yongxue Wang ◽  
Hongjie Wen

A non-reflective SPH (Smoothed Particle Hydrodynamics) wave flume is developed to study wave transformation over the deep-sea platform reef with a steep reef-face. The left and right boundaries of the flume are modeled using the periodic boundary conditions and a water circulation technology, and a momentum source wave maker is applied to generate the required wave. Wave transformation over the reef-flat is analyzed and compared with the experimental data. The results show that the present SPH model can effectively overcome the non-physical rise of the mean water level in the lagoon and over the reef-flat, which can be observed in the long time simulation with the traditional vertical two-dimensional numerical model. Furthermore, the present model can accurately reproduce the wave breaking process and give a good agreement with the experimental data in terms of the spatial distribution of wave height and wave setup on the reef flat.

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.


2018 ◽  
Vol 15 (06) ◽  
pp. 1850046 ◽  
Author(s):  
Man Hu ◽  
Qiuqiang Liu ◽  
Fei Wu ◽  
Mengting Yu ◽  
Shenghua Jiang

Landslide can usually be induced by a strong earthquake, and it causes very serious property damage and human casualties. Modeling of post-failure flow of landslides is one of the important approaches that can be used to simulate landslide flow developments and predict the landslide hazard zone. In this paper, a Smoothed Particle Hydrodynamics (SPH) model based on the constitution of elastic-plastic constitutive mechanics for soil has been developed for simulating the behavior of a class of geo-materials under the seismic loadings. Our SPH-Soil model considers the plastic behavior of the materials, and hence it is very important for more accurate and realistic simulations of geo-materials of soil type. The implemented materials laws in the SPH-Soil code include classical elastic-plasticity with a linear elastic part, and different applicable yield surfaces with nonassociated flow rules. In order to apply this model to actual landslide modeling the Geographic Information System (GIS) is utilized to generate site-specific models. We have thus developed a C# code to generate the particles of a given landslide site, which produces realistic particle mass and actual complicated boundaries for the SPH-Soil model. With GIS enabled, complex topography and irregular boundary can be accurately and easily built up. Then the SPH-Soil code has been applied to the well-known Daguangbao landslide, which was triggered by Wenchuan earthquake in 2008. The topographies after failure were compared with that obtained from field collected data and good agreement was found.


2020 ◽  
Vol 17 (10) ◽  
pp. 2050009
Author(s):  
Sisi Tan ◽  
Mingze Xu

Numerical modeling of whole blood still faces great challenges although significant progress has been achieved in recent decades, because of the large differences of physical and geometric properties among blood components, including red blood cells (RBCs), platelets (PLTs) and white blood cells (WBCs). In this work, we develop a three-dimensional (3D) smoothed particle hydrodynamics (SPH) model to study the whole blood in shear flow. The immersed boundary method (IBM) is used to deal with the interaction between the fluid and cells, which provides a possibility to model the RBCs, PLTs and WBCs simultaneously. The deformation of a small capsule, comparable to a PLT in size, is first examined to show the feasibility of SPH model for the PLTs’ behaviors. The motion of a single RBC in shear flow is then studied, and three typical modes, tank-treading, swinging and tumbling motions, are reproduced, which further confirm the reliability of the SPH model. After that, a simulation of the whole blood in shear flow is carried out, in which the margination trend is observed for both PLTs and WBC. This shows the capability of SPH model with IBM for the simulation of whole blood.


2018 ◽  
Vol 16 (02) ◽  
pp. 1846008
Author(s):  
X. J. Ma ◽  
M. Geni ◽  
A. F. Jin

Based on the fundamental theory of smoothed-particle hydrodynamics (SPH), a feasible algorithm for fluid–solid coupling on interface is applied to describe the dynamic behavior of fluid and solid by utilizing continuum mechanics governing equations. Numerical simulation is conducted based on the proposed SPH model and the fluid–solid interface coupling algorithm, and good agreement is observed with the experiment results. It is shown in the results that the present SPH model is able to effectively and accurately simulate the free-surface flow of fluid, deformation of the elastic solid and the fluid–solid impacting.


2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Kai Gong ◽  
Songdong Shao ◽  
Hua Liu ◽  
Pengzhi Lin ◽  
Qinqin Gui

This paper presents a smoothed particle hydrodynamics (SPH) modeling technique based on the cylindrical coordinates for axisymmetrical hydrodynamic applications, thus to avoid a full three-dimensional (3D) numerical scheme as required in the Cartesian coordinates. In this model, the governing equations are solved in an axisymmetric form and the SPH approximations are modified into a two-dimensional cylindrical space. The proposed SPH model is first validated by a dam-break flow induced by the collapse of a cylindrical column of water with different water height to semi-base ratios. Then, the model is used to two benchmark water entry problems, i.e., cylindrical disk and circular sphere entry. In both cases, the model results are favorably compared with the experimental data. The convergence of model is demonstrated by comparing with the different particle resolutions. Besides, the accuracy and efficiency of the present cylindrical SPH are also compared with a fully 3D SPH computation. Extensive discussions are made on the water surface, velocity, and pressure fields to demonstrate the robust modeling results of the cylindrical SPH.


2013 ◽  
Vol 353-356 ◽  
pp. 3531-3536
Author(s):  
Kun Zheng ◽  
Zhao Chen Sun ◽  
Chang Ping Chen ◽  
Feng Zhou

The numerical wave flume was established for simulating the impact effects of regular waves on horizontal plate by adopting the method of Smoothed Particle Hydrodynamics (SPH).The impact process of regular waves on horizontal plate was analyzed, and the impact pressure-time curves were gotten using a new estimation method. The comparison of numerical results and experimental results shows that the new estimation method can predict the peak impact pressure more accurately.


Author(s):  
Sohaib Rashid Sulaiman Alahmed ◽  
Qingping Zou

A Smoothed Particle Hydrodynamics (SPH) method is used to investigate the flood characteristics occurring in an idealized city with two different building layouts: aligned layout and 22.5o skewed layout with respect to the direction of the incoming flow. The model results show that the water elevation is higher for the skewed city layout than that for the aligned city layout. The force due to the flood impact on the majority of buildings tend to be higher for the former than that for the latter. The complex flow features including a hydraulic jump during the flooding event are well captured by the SPH model.


2013 ◽  
Vol 7 (6) ◽  
pp. 614-620 ◽  
Author(s):  
Jingsi Wang ◽  
◽  
Keita Shimada ◽  
Masayoshi Mizutani ◽  
Tsunemoto Kuriyagawa

Hammering action plays a primary role in material removal in ultrasonic machining (USM). In the present study, Smoothed Particle Hydrodynamics (SPH) is used to simulate the hammering action of a single silicon carbide abrasive particle on a float glass workpiece, and the implications for crack initiation and propagation on the workpiece are discussed in detail. The adequacy of the SPH model is verified through an experiment that utilizes a stationary ultrasonic drilling machine. It is shown that the distribution and size of the cracks on the sample workpiece are well in agreement with the simulation results. The current study presents a new way to understand the material removal process of USM, which is extremely significant for the further improvement of the performance of USM techniques.


2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Darcy Q. Hou ◽  
Arris S. Tijsseling ◽  
Zafer Bozkus

The impact force on an elbow induced by traveling isolated liquid slugs in a horizontal pipeline is studied. A literature review reveals that the force on the elbow is mainly due to momentum transfer in changing the fluid flow direction around the elbow. Therefore, to accurately calculate the magnitude and duration of the impact force, the slug arrival velocity at the elbow needs to be well predicted. The hydrodynamic behavior of the slug passing through the elbow needs to be properly modeled too. A combination of 1D and 2D models is used in this paper to analyze this problem. The 1D model is used to predict the slug motion in the horizontal pipeline. With the obtained slug arrival velocity, slug length, and driving air pressure as initial conditions, the 2D Euler equations are solved by the smoothed particle hydrodynamics (SPH) method to analyze the slug dynamics at the elbow. The 2D SPH solution matches experimental data and clearly demonstrates the occurrence of flow separation at the elbow, which is a typical effect of high Reynolds flows. Using the obtained flow contraction coefficient, an improved 1D model with nonlinear elbow resistance is proposed and solved by SPH. The 1D SPH results show the best fit with experimental data obtained so far.


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