Bio: Bogdan Iwanowski is an academic researcher. The author has contributed to research in topics: Volume of fluid method & Computational fluid dynamics. The author has an hindex of 8, co-authored 14 publications receiving 700 citations.
TL;DR: In this paper, the authors considered some aspects of water impact and green water loading by numerically investigating a dambreak problem and water entry problems, based on the Navier-Stokes equations that describe the flow of a viscous fluid.
01 Jan 2009
TL;DR: In this article, a semi-submersible offshore platform is used to simulate flow around a semiautomain offshore platform due to an incoming regular wave, where wave run-up on the columns and under-deck fluid impact phenomena are investigated on high-accuracy computational grids with number of cells being in range of 10 millions.
Abstract: Use of CFD tools for industrial offshore applications is a common practice nowadays. So is the need for validation of such tools against experimental results. This paper presents one of the CFD tools, ComFLOW, which solves Navier-Stokes equations and employs an improved Volume of Fluid (iVOF) method to find temporary location of fluid’s free surface. The code is used to simulate flow around a semi-submersible offshore platform due to an incoming regular wave. In particular, wave run-up on the semi’s columns and under-deck fluid impact phenomena are investigated on high-accuracy computational grids with number of cells being in range of 10 millions. Results of numerical simulations are compared with experimental data and focus is on local fluid flow details in immediate vicinity of the platform. Wave run-up on the platform’s columns and fluid pressures at various locations, including under-deck impact, are reported and verified against the experiment for a range of incoming wave heights.Copyright © 2009 by ASME
••31 Oct 2011
TL;DR: In this paper, the authors present a short overview of the ComFLOW method, some recent results and future plans for predicting extreme wave forces on offshore platforms and offloading vessels, and the prediction of impact forces on coastal protection structures.
Abstract: Hydrodynamic wave loading on structures plays an important role in areas such as coastal protection, harbor design and offshore constructions (FPSO’s, mooring), and there is a need for its prediction up to a detailed level (max./min. pressures, duration of pressure peaks, shear stresses, etc.). In close cooperation with industry, long-year joint-industry projects are carried out to develop a numerical simulation method: the CFD method ComFLOW. The two major application areas are the prediction of extreme wave forces on offshore platforms and offloading vessels, and the prediction of impact forces on coastal protection structures. The paper will present a short overview of the method, some recent results and future plans.Copyright © 2011 by ASME
••01 Jan 2002
TL;DR: In this article, the simulation of green water on the foredeck of an FPSO is presented, where the waves are modeled as a dam of water around the deck which is suddenly released.
Abstract: Results of computer simulation of wave and green water loading on floating offshore structures are presented. The simulation program used is a CFD code which solves the Navier-Stokes equations that describe flow of incompressible viscous fluids. The Navier-Stokes equations are discretised using a Finite Volume method on a Cartesian grid with staggered variables. The free surface is displaced using a Volume Of Fluid based algorithm combined with a local height function. In this paper results of validation and sensitivity tests of simulation of green water on the foredeck of an FPSO are presented. Here, the waves are modeled as a dam of water around the deck which is suddenly released. Furthermore, wave loading from impact of regular waves on a SPAR platform is computed and compared with experimental results. The program is found to be robust and the computational results show good agreement with the experiments.Copyright © 2002 by ASME
01 Jan 2004
TL;DR: In this article, a smoothed particle hydrodynamics model with numerical diffusive terms is used to analyze violent water flows and boundary conditions on solid surfaces of arbitrary shape are enforced with a new technique based on fixed ghost particles.
TL;DR: In this paper, the authors proposed modified MPS methods for the prediction of wave impact pressure on a coastal structure by introducing new formulations for the pressure gradient and a new formulation of the source term of the Poisson Pressure Equation (PPE).
TL;DR: In this paper, the authors conduct experimental measurements on a dam break flow over a horizontal dry bed in order to provide a detailed insight, with emphasis on the pressure loads, into the dynamics of the dam break wave impacting a vertical wall downstream the dam.
TL;DR: Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability.
Abstract: Smoothed Particle Hydrodynamics (SPH) is a numerical method commonly used in Computational Fluid Dynamics (CFD) to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs) or Graphics Processor Units (GPUs), a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA) of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability.
TL;DR: Ferrand et al. as discussed by the authors proposed a new approach based on a renormalising factor for writing all boundary terms, which significantly improved traditional wall treatment in smoothed particle hydrodynamics, for pressure forces, wall friction and turbulent conditions.
Abstract: Computational / Numerical Methods > International Journal for Numerical Methods in Fluids > Early View > AbstractJOURNAL TOOLS Get New Content Alerts Get RSS feed Save to My Profile Get Sample Copy Recommend to Your Librarian JOURNAL MENU Journal HomeFIND ISSUES Current Issue All IssuesFIND ARTICLES Early View Most Accessed Most CitedGET ACCESS Subscribe / Renew FOR CONTRIBUTORS OnlineOpen Author Guidelines Submit an ArticleABOUT THIS JOURNAL News Overview Editorial Board Permissions Advertise ContactSPECIAL FEATURES La Tex Class File Numerical Engineering Backfile Collection FREE Engineering sample issues Other Numerical Engineering Journals Biomedical Engineering Zienkiewicz Award 2010 Keyword Tag Cloud Wiley Job Network To our Authors: newsletterNumerical Engineering JournalsWiley Job NetworkWiley Science Jobs Hydraulics Product Support Engineer Salary: �35000 - �40000 per annum + package Location: Berkshire Product Support Engineer - Hydraulics Permanent Salaried with company benefits package Working as part of a dedicated Sales? Mechanical Engineer - Sensor Components - Oil & Gas - Cambridge Salary: Negotiable Location: Cambridge Mechanical Engineer - Sensor Components - Oil & Gas - Cambridgeshire One of the country's leading Scientific Consultancy's f? Usability Design Engineer - Medical Devices - Creative Design Salary: Negotiable Location: Hertfordshire Usability Design Engineer - Medical Devices - Creative Design - Hertfordshire Are you an experienced Design Engineer with a ? Product Designer - Draughtsperson - SolidWorks - Hertfordshire Salary: Negotiable Location: Hertfordshire Product Designer - Draughtsperson - SolidWorks - Hertfordshire A well established Medical Devices Company, based in Hertford? Research Engineer - Medical Imaging - Edinburgh - Photonics Salary: Negotiable Location: Edinburgh Research Engineer - Medical Imaging - Edinburgh - Photonics A growing Medical Imaging company, based in Edinburgh, are curre?Find more Wiley Science Jobs �Research ArticleUnified semi-analytical wall boundary conditions for inviscid, laminar or turbulent flows in the meshless SPH method M. Ferrand1,*, D.R. Laurence2, B.D. Rogers2, D. Violeau3, C. Kassiotis3Article first published online: 20 MAR 2012DOI: 10.1002/fld.3666Copyright � 2012 John Wiley & Sons, Ltd.IssueCover image for Vol. 70 Issue 6International Journal for Numerical Methods in FluidsEarly View (Online Version of Record published before inclusion in an issue)Additional Information(Show All)How to CiteAuthor InformationPublication HistorySEARCHSearch ScopeSearch String Advanced > Saved Searches >ARTICLE TOOLS Get PDF (12213K) Save to My Profile E-mail Link to this Article Export Citation for this Article Get Citation Alerts Request PermissionsMore Sharing ServicesShare|Share on citeulikeShare on connoteaShare on deliciousShare on www.mendeley.comShare on twitter Abstract Article References Cited ByView Full Article (HTML) Get PDF (12213K)Keywords: wall boundary conditions; Navier?Stokes; smoothed particles hydrodynamics; Lagrangian; laminar flow; viscous flows; turbulent flow; meshfree; free surfaceSUMMARYWall boundary conditions in smoothed particle hydrodynamics (SPH) is a key issue to perform accurate simulations. We propose here a new approach based on a renormalising factor for writing all boundary terms. This factor depends on the local shape of a wall and on the position of a particle relative to the wall, which is described by segments (in two-dimensions), instead of the cumbersome fictitious or ghost particles used in most existing SPH models. By solving a dynamic equation for the renormalising factor, we significantly improve traditional wall treatment in SPH, for pressure forces, wall friction and turbulent conditions. The new model is demonstrated for cases including hydrostatic conditions for still water in a tank of complex geometry and a dam break over triangular bed profile with sharp angle where significant improved behaviour is obtained in comparison with the conventional boundary techniques. The latter case is also compared with a finite volume and volume-of-fluid scheme. The performance of the model for a two-dimensional laminar flow in a channel is demonstrated where the profiles of velocity are in agreement with the theoretical ones, demonstrating that the derived wall shear stress balances the pressure gradient. Finally, the performance of the model is demonstrated for flow in a schematic fish pass where both the velocity field and turbulent viscosity fields are satisfactorily reproduced compared with mesh-based codes.