Particle methods in ocean and coastal engineering

Water waves over a muddy bed: a two-layer Stokes' boundary layer model

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave-structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2019.0801

Review of smoothed particle hydrodynamics: towards converged Lagrangian flow modelling.

Numerical investigation of the solitary wave breaking over a slope by using the finite particle method

Enhancement of pressure calculation in projection-based particle methods by incorporation of background mesh scheme

Summary
Precise simulation of the propagation of surface water waves, especially when involving breaking wave, takes a significant place in computational fluid dynamics. Because of the strong nonlinear properties, the treatment of large surface deformation of free surface flow has always been a challenging work in the development of numerical models. In this paper, the moving particle semi-implicit (MPS) method, an entirely Lagrangian method, is modified to simulate wave motion in a 2-D numerical wave flume preferably. In terms of consecutive pressure distribution, a new and simple free surface detection criterion is proposed to enhance the free surface recognition in the MPS method. In addition, a revised gradient model is deduced to diminish the effect of nonuniform particle distribution and then to reduce the numerical wave attenuation occurring in the original MPS model. The applicability and stability of the improved MPS method are firstly demonstrated by the calculation of hydrostatic problem. It is revealed that these modifications are effective to suppress the pressure oscillation, weaken the local particle clustering, and boost the stability of numerical algorithm. It is then applied to investigate the propagation of progressive waves on a flat bed and the wave breaking on a mild slope. Comparisons with the analytical solutions and experimental results indicate that the improved MPS model can give better results about the profiles and heights of surface waves in contrast with the previous MPS models. Copyright © 2017 John Wiley & Sons, Ltd.

Improvement of moving particle semi-implicit method for simulation of progressive water waves

This study is focused on deepening our insight into rheological properties of soft mud under oscillatory forces, on quantifying their effects on the interaction between water waves and mud bed, and especially on the resultant mud mass transport. On the basis of a large number of experiments, an empirical rheological model and formulas for model parameters are proposed. In addition, a simple analytical model for evaluating the temporal change in mud water content ratio under waves is derived. Using these two models, a vertical 2-D numerical model is developed to predict the wave-induced bed mud motion and the resultant mud mass transport velocity. Comparisons between the calculations and measurements are presented.

https://icce-ojs-tamu.tdl.org/icce/index.php/icce/article/download/5539/5213

Analysis of mud mass transport under waves using an empirical rheological model

Numerical simulation of solitary waves overtopping on a sloping sea dike using a particle method

The rheological response of soft mud to oscillatory forcing was studied experimentally with a dynamic rotary shear viscometer. The mud showed combined features of viscous, elastic and plastic mater...

Qin Jiang

Papers

Enhancement of pressure calculation in projection-based particle methods by incorporation of background mesh scheme

Improvement of moving particle semi-implicit method for simulation of progressive water waves

Analysis of mud mass transport under waves using an empirical rheological model

Numerical simulation of solitary waves overtopping on a sloping sea dike using a particle method

Rheological Properties of Soft Mud and a Numerical Model for Its Motion Under Waves