SPH Simulations of Ship Propeller Induced Harbour Bed Erosion

2012 ◽  
Author(s):  
Christian Ulrich ◽  
Thomas Rung
Keyword(s):  
Open Water ◽  
Local Flow ◽  
Stress Criterion ◽  
Counter Measures ◽  
Water Characteristics ◽  
Bed Erosion ◽  
Particle Hydrodynamics ◽  
Suspension Layer ◽  
Smoothed Particle ◽  
Ship Propeller

The paper reports on the predictive prospects of Smoothed-Particle-Hydrodynamics (SPH) for simulations of ship propeller induced scours in harbours. Such erosions represent unpleasant phenomena, especially if they occur close to quay walls, and generate cost intensive counter measures. These measures are usually based on a rather weak background knowledge. SPH simulations can help to analyse the erosional processes and to understand the interaction between ship, water, soil and structure. In the present research, a body-force propulsor model based on the open water characteristics is used to represent the ship’s propeller. The evolution of the liquid and granular phase particles is obtained from an SPH-integration of the continuity and momentum equations. The fluid is considered to be Newtonian and the viscosity of the soil-phase is modelled in line with the Mohr-Coulomb yield stress criterion. Water and soil particles interacting in a suspension layer are assigned to a viscosity that is derived from a Chézy-relation between the shear stress and the local flow velocity. A variable particle resolution strategy is applied to handle large domains, in which the areas around the ship hull demand a fine resolution. A complex full-scale application example included refers to the starting sequence of a container ship propeller.

Screws Working in Behind and Prediction of the Performance of Full Ships

1990 ◽  
Vol 34 (04) ◽  
pp. 262-282
Author(s):  
Christopher Grigson
Keyword(s):  
Velocity Field ◽  
Scale Effect ◽  
Open Water ◽  
Full Scale ◽  
Constant Speed ◽  
Water Characteristics ◽  
Torque Coefficient ◽  
Ship Propeller

Constant speed propulsion tests of full models are investigated. The propulsion factors are found to vary with propeller speed, n. When the tests extend to idling conditions, the nominal wake fraction and the complete propeller-hull behind characteristics ϕ(u/nd) are determined. Fifteen designs of hull and screw are investigated. In some, the coupling between the velocity field of the hull and that of the screw is found to be strong. The behind characteristics depend both on the design of the screw and on the design of the hull. The same design of screw may efficiently power hulls of quite different form. A second kind of behind characteristic, ψ[(1 -ω)u/nd], is introduced. It is obtained from ϕ and it can be compared directly with the open-water characteristics. It is shown experimentally that in a full ship the open-water characteristics are not generally an accurate substitute for the behind ones. Therefore ϕ or ψ ought to be used when predicting ship propeller speed Ν and power. A condition for running the propulsion test is derived in which, after correction for the scale effect of blade friction on torque, the full-scale behind torque coefficient may be found from the model one. Furthermore, in this test condition Ν may be rigorously scaled from n, measured on the model. Thus full-scale performance is determined. Limited tests of the method appear accurate.

scholarly journals Moving-mesh hydrodynamics with the AREPO code

2010 ◽  
Vol 6 (S270) ◽  
pp. 203-206 ◽  
Author(s):  
Volker Springel
Keyword(s):  
Hyperbolic Conservation Laws ◽  
Voronoi Tessellation ◽  
Compressible Turbulence ◽  
Local Flow ◽  
Hyperbolic Conservation ◽  
Particle Hydrodynamics ◽  
Automatic Adaptivity ◽  
Smoothed Particle ◽  
Finite Volume Approach ◽  
Hydrodynamical Simulations

AbstractAt present, hydrodynamical simulations in computational star formation are either carried out with Eulerian mesh-based approaches or with the Lagrangian smoothed particle hydrodynamics (SPH) technique. Both methods differ in their strengths and weaknesses, as well as in their error properties. It would be highly desirable to find an intermediate discretization scheme that combines the accuracy advantage of mesh-based methods with the automatic adaptivity and Galilean invariance of SPH. Here we briefly describe the novel AREPO code which achieves these goals based on a moving unstructured mesh defined by the Voronoi tessellation of a set of discrete points. The mesh is used to solve the hyperbolic conservation laws of ideal hydrodynamics with a finite volume approach, based on a second-order unsplit Godunov scheme with an exact Riemann solver. A particularly powerful feature is that the mesh-generating points can in principle be moved arbitrarily. If they are given the velocity of the local flow, an accurate Lagrangian formulation of continuum hydrodynamics is obtained that features a very low numerical diffusivity and is free of mesh distortion problems. If the points are kept fixed, the scheme is equivalent to a Eulerian code on a structured mesh. The new AREPO code appears especially well suited for problems such as gravitational fragmentation or compressible turbulence.

scholarly journals Numerical Simulations Of Hydrodynamic Open-Water Characteristics Of A Ship Propeller

2016 ◽  
Vol 23 (4) ◽  
pp. 16-22 ◽  
Author(s):  
Judyta Felicjancik ◽  
Sebastian Kowalczyk ◽  
Karol Felicjancik ◽  
Krzysztof Kawecki
Keyword(s):  
Numerical Methods ◽  
Numerical Simulations ◽  
Experimental Research ◽  
Open Water ◽  
Research Centre ◽  
Model Data ◽  
Kinematic Data ◽  
Water Characteristics ◽  
Ship Propeller ◽  
Real Scale

Abstract The paper presents the results of numerical simulations of ship propeller operation bearing the name of Propeller Open Water (POW) Tests. The object of tests was a sample ship propeller (PPTC1), the geometrical and kinematic data of which are available, along with the results of model tests, on the official page of the research centre involved in the measurements. The research aimed at verifying the correctness of results of numerical simulations performed in the model and real scale. The results of numerical analyses performed in the model scale were confronted with those measured in the experiment. Then, making use of dimensionless coefficients which characterise propeller’s operation, the recorded model data were extrapolated to real conditions and compared with corresponding results of simulations. Both the numerical simulations and the experimental research were performed for the same propeller load states. The reported research is in line with other activities which aim at developing advanced numerical methods to support the process of ship propeller designing.

Simulation de l'écoulement au cours du procédé de rotomoulage par la méthode Smoothed Particle Hydrodynamics (SPH)

2008 ◽  
Vol 96 (6) ◽  
pp. 263-268 ◽  
Author(s):  
E. Mounif ◽  
V. Bellenger ◽  
A. Ammar ◽  
R. Ata ◽  
P. Mazabraud ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Numerical Simulation of Flow in Complex Geometries by Using Smoothed Particle Hydrodynamics

2020 ◽  
Vol 59 (40) ◽  
pp. 18236-18246
Author(s):  
Tianwen Dong ◽  
Yadong He ◽  
Jianchun Wu ◽  
Shiyu Jiang ◽  
Xingyuan Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Smoothed Particle Hydrodynamics ◽  
Complex Geometries ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

scholarly journals Review of smoothed particle hydrodynamics: towards converged Lagrangian flow modelling

2020 ◽  
Vol 476 (2241) ◽  
pp. 20190801
Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Graphics Processing Units ◽  
Wave Structure ◽  
Free Form ◽  
Mesh Free ◽  
Weakly Compressible ◽  
Particle Hydrodynamics ◽  
Massively Parallel Computing ◽  
Smoothed Particle ◽  
Graphics Processing

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.

Smoothed particle hydrodynamics versus finite element method for blast impact

2013 ◽  
Vol 61 (1) ◽  
pp. 111-121 ◽  
Author(s):  
T. Jankowiak ◽  
T. Łodygowski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Smoothed Particle Hydrodynamics ◽  
Concrete Slab ◽  
The Finite Element Method ◽  
Particle Hydrodynamics ◽  
Mesh Density ◽  
Smoothed Particle ◽  
Element Method

Abstract The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper

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