scholarly journals A parameter-free total Lagrangian smooth particle hydrodynamics algorithm applied to problems with free surfaces

2021 ◽  
Author(s):  
Kenny W. Q. Low ◽  
Chun Hean Lee ◽  
Antonio J. Gil ◽  
Jibran Haider ◽  
Javier Bonet
Keyword(s):  
Ad Hoc ◽  
Wide Spectrum ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Point Of View ◽  
Numerical Dissipation ◽  
Lagrangian Description ◽  
Smooth Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Sph Algorithm

AbstractThis paper presents a new Smooth Particle Hydrodynamics computational framework for the solution of inviscid free surface flow problems. The formulation is based on the Total Lagrangian description of a system of first-order conservation laws written in terms of the linear momentum and the Jacobian of the deformation. One of the aims of this paper is to explore the use of Total Lagrangian description in the case of large deformations but without topological changes. In this case, the evaluation of spatial integrals is carried out with respect to the initial undeformed configuration, yielding an extremely efficient formulation where the need for continuous particle neighbouring search is completely circumvented. To guarantee stability from the SPH discretisation point of view, consistently derived Riemann-based numerical dissipation is suitably introduced where global numerical entropy production is demonstrated via a novel technique in terms of the time rate of the Hamiltonian of the system. Since the kernel derivatives presented in this work are fixed in the reference configuration, the non-physical clumping mechanism is completely removed. To fulfil conservation of the global angular momentum, a posteriori (least-squares) projection procedure is introduced. Finally, a wide spectrum of dedicated prototype problems is thoroughly examined. Through these tests, the SPH methodology overcomes by construction a number of persistent numerical drawbacks (e.g. hour-glassing, pressure instability, global conservation and/or completeness issues) commonly found in SPH literature, without resorting to the use of any ad-hoc user-defined artificial stabilisation parameters. Crucially, the overall SPH algorithm yields equal second order of convergence for both velocities and pressure.

An Algorithm for Fluid–Solid Coupling Based on SPH Method and Its Preliminary Verification

2018 ◽  
Vol 16 (02) ◽  
pp. 1846008
Author(s):  
X. J. Ma ◽  
M. Geni ◽  
A. F. Jin
Keyword(s):  
Elastic Solid ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Feasible Algorithm ◽  
Coupling Algorithm ◽  
Good Agreement

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.

scholarly journals A Coupled Model for Wave Run-up Simulation

2018 ◽  
Author(s):  
Iryanto ◽  
Sri Redjeki Pudjaprasetya
Keyword(s):  
Euler Equations ◽  
Coupled Model ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Flow Problems ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Run Up ◽  
Sloping Beach

Simplified models like the shallow water equations (SWE) are commonly adopted for describing a wide range of free surface flow problems, like flows in rivers,lakes, estuaries, or coastal areas. In the literature, numerical methods for the SWE are mostly mesh-based. However, this macroscopic approach is unable to accurately represent the complexity of flows near coastlines, where waves nearly break. This fact prompted the idea of coupling the mesh-based SWE model with a meshless particlemethod for solving the Euler equations. In a previous paper, a method to couple the staggered scheme SWE and the smoothed particle hydrodynamics (SPH) Euler equations was developed and discussed. In this article, this coupled model is used for simulating solitary wave run-up on a sloping beach. The results show strong agreement with the experimental data of Synolakis. Simulations of wave overtopping over aseawall were also performed.

scholarly journals Particle-based modeling and meshless simulation of flows with Smoothed Particle Hydrodynamics

2019 ◽  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Atomic Scale ◽  
Particle Methods ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Mesh Free Methods ◽  
Mesh Grid

<p>Smoothed Particle Hydrodynamics (SPH) is a promising simulation technique in the family of Lagrangian mesh-free methods, especially for flows that undergo large deformations. Particle methods do not require a mesh (grid) for their implementation, in contrast to conventional Computational Fluid Dynamics (CFD) methods. Conventional CFD algorithms have reached a very good level of maturity and the limits of their applicability are now fairly well understood. In this paper we investigate the application of the SPH method in Poiseuille and transient Couette flow along with a free surface flow example. Algorithmically, the method is viewed within the framework of an atomic-scale method, Molecular Dynamics (MD). In this way, we make use of MD codes and computational tools for macroscale systems.</p>

scholarly journals Numerical modeling of free surface flow in hydraulic structures using Smoothed Particle Hydrodynamics

2016 ◽  
Vol 40 (23-24) ◽  
pp. 9821-9834 ◽  
Author(s):  
Mahdiyar Khanpour ◽  
Amir Reza Zarrati ◽  
Morteza Kolahdoozan ◽  
Ahmad Shakibaeinia ◽  
Sadegh Jafarinik
Keyword(s):  
Numerical Modeling ◽  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Hydraulic Structures ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

scholarly journals Crack growth pattern analysis of monolithic glass ceramic on a titanium abutment for single crown implant restorations using smooth particle hydrodynamics algorithm

2021 ◽  
Vol 13 (1) ◽  
pp. 7-11
Author(s):  
Mohammad Kashfi ◽  
Parisa Fakhri ◽  
Ataollah Ghavamian ◽  
Payam Pourrabia ◽  
Fatemeh Salehi Ghalesefid ◽  
...  
Keyword(s):  
Crack Growth ◽  
Dynamic Loading ◽  
Glass Ceramic ◽  
Growth Direction ◽  
Smooth Particle Hydrodynamics ◽  
Incisal Edge ◽  
Particle Hydrodynamics ◽  
Implant Crown ◽  
Crack Growth Direction ◽  
Sph Algorithm

Background. Glass ceramic materials have multiple applications in various prosthetic fields. Despite the many advantages of these materials, they still have limitations such as fragility and surface machining and ease of repairing. Crack propagation has been a typical concern in fullceramic crowns, for which many successful numerical simulations have been carried out using the extended finite element method (XFEM). However, XFEM cannot correctly predict a primary crack growth direction under dynamic loading on the implant crown. Methods. In this work, the dental implant crown and abutment were modeled in CATIA V5R19 software using a CT-scan technique based on the human first molar. The crown was approximated with 39514 spherical particles to reach a reasonable convergence in the results. In the present work, glass ceramic was considered the crown material on a titanium abutment. The simulation was performed for an impactor with an initial velocity of 25 m/s in the implant-abutment axis direction. We took advantage of smooth particle hydrodynamics (SPH) such that the burden of defining a primary crack growth direction was suppressed. Results. The simulation results demonstrated that the micro-crack onset due to the impact wave in the ceramic crown first began from the crown incisal edge and then extended to the margin due to increased stress concentration near the contact region. At 23.36 µs, the crack growth was observed in two different directions based on the crown geometry, and at the end of the simulation, some micro-cracks were also initiated from the crown margin. Moreover, the results showed that the SPH algorithm could be considered an alternative robust tool to predict crack propagation in brittle materials, particularly for the implant crown under dynamic loading. Conclusion. The main achievement of the present study was that the SPH algorithm is a helpful tool to predict the crack growth pattern in brittle materials, especially for ceramic crowns under dynamic loading. The predicted crack direction showed that the initial crack was divided into two branches after its impact, leading to the crown fracture. The micro-crack initiated from the crown incisal edge and then extended to the crown margin due to the stress concentration near the contact area.

scholarly journals Numerical investigations of the free surface flow around a surface piercing hydrofoil

2021 ◽  
Vol 44 ◽  
pp. 87-94
Author(s):  
Costel Ungureanu
Keyword(s):  
Free Surface ◽  
Free Surface Flow ◽  
Efficiency Index ◽  
Surface Flow ◽  
Point Of View ◽  
Breaking Wave ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Boundary Layer Interaction ◽  
Wave Effects

Starting with January 2013, naval architects faces new challenges, as all ships greater than 400 tons must comply with energy efficiency index (MPEC 62, 2011). From ship hydrodynamics point of view one handy solution is using Energy Saving Devices (ESD), with the main purpose to improve the flow parameters entering the propeller. For ballast loading condition the ESD may intersect the free surface disturbing and complicating the flow due to free surface /boundary layer interaction, turbulence and breaking wave effects that coexist and which are not completely clarified so far. Therefore, a free surface flow around a NACA 0012 surface piercing hydrofoil is numerically investigated and the results are compared to experimental results obtained in the Towing Tank of the Naval Architecture Faculty, “Dunarea de Jos” University of Galati. The comparison includes drag and free surface elevation on hydrofoil surface together with numerical uncertainty.

Free Surface Flow Analysis by Smoothed Particle Hydrodynamics

2006 ◽  
Author(s):  
Jun Imasato ◽  
Yuzuru Sakai
Keyword(s):  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Particle Density ◽  
Flow Analysis ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Pressure Poisson Equation ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Marker And Cell Method

In this study a new computational algorithm to enforce incompressibility in free surface flow analysis using Smoothed Particle Hydrodynamics (SPH) is presented. The method uses two steps. The first step is a fractional step for solving velocity field forward in time without incompressibility. Then the second step is computed to compensate the pressure Poisson equation using the mass constant equation in a particle field. This method is composed of the above two steps and is similar to SMAC (Simplified Marker and Cell) method commonly used in CFD. However in SPH simulation, the introduction of incompressibility of fluid is easily realized using the particle density concept and the boundary of free surface of fluid is also controlled conveniently by the concept. In this study the algorithm is applied to sloshing problems of vessels with fluid. The numerical results using this algorithm show good results in the behaviors of free surface flow and the pressure evaluations at the wall of the vessels.

A Coupled SPH-FEM Solver for Modeling Surface Effect Ship (SES) Bow Seal Dynamics

2020 ◽  
Author(s):  
John Gilbert ◽  
Leigh McCue
Keyword(s):  
High Speed ◽  
Surface Effect ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Numerical Predictions ◽  
Surface Effect Ship ◽  
Particle Hydrodynamics ◽  
Hyper Elastic ◽  
Smoothed Particle ◽  
The University

Abstract The life of Surface Effect Ship (SES) bow and finger seals are often short-lived due to a combination of environmental effects and dynamic loading due to high-speed operation. Improving SES seal robustness requires a deeper understanding of the dynamics and loads seen by SES skirt seals during operation. In this work, we present the results of a validation study performed for a coupled, smoothed particle hydrodynamics (SPH) - finite element method (FEM) solver developed to study fluid-structure impact and free-surface flow interaction with hyper-elastic structures. This work continues and extends the earlier coupled SPH-FEM approach of Yang et al. [1]. Numerical predictions for skirt seal displacement are compared against the experimental observations of Zalek and Doctors performed by the Marine Hydrodynamics Laboratory at the University of Michigan [2].

scholarly journals IMPROVED SMOOTHED PARTICLE HYDRODYNAMICS WITH RANS FOR FREE-SURFACE FLOW PROBLEMS

2012 ◽  
Vol 09 (01) ◽  
pp. 1240001 ◽  
Author(s):  
J. R. SHAO ◽  
M. B. LIU ◽  
X. F. YANG ◽  
L. CHENG
Keyword(s):  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Computational Accuracy ◽  
Sph Method ◽  
Flow Problems ◽  
Kernel Gradient Correction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

This paper presents an implementation of an improved smoothed particle hydrodynamics (SPH) method for numerical simulation of free-surface flow problems. The presented SPH method involves two major modifications on the traditional SPH method: (1) kernel gradient correction (KGC) and density correction to improve the computational accuracy in particle approximation and (2) RANS turbulence model to capture the inherent physics of flow turbulence. In the simulation, artificial compressibility for modeling incompressible fluid and ghost particles for treating solid boundaries are both applied. The presented SPH has been applied to two dam-breaking problems. We demonstrated that the presented SPH method has very good performance with more accurate flow patterns and pressure field distribution.

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