Numerical Study of Wave-Driven Impact of a Sea Ice Floe on a Circular Cylinder

2016 ◽  
Author(s):  
Biao Su ◽  
Karl Gunnar Aarsæther ◽  
David Kristiansen
Keyword(s):  
Numerical Model ◽  
Circular Cylinder ◽  
Sea Ice ◽  
Numerical Study ◽  
Offshore Structures ◽  
Experimental Result ◽  
Recent Experimental Study ◽  
Pressure Area ◽  
Closed Form Analytical Solution ◽  
The Impact

This paper presents a numerical model for simulating wave-driven ice floe–structure interactions, which is integrated in a software framework (FhSim) for time-domain simulation of marine systems. The FhSim framework has proved to be a valuable tool for research and development within different applications and areas [1]. In this study, the wave-driven impact of a sea ice floe on a circular cylinder is simulated. The simulation setup refers to a recent experimental study [2], and the kinematics of ice floe in wave is compared with the experimental result. As the impact forces were not measured in the experiment, a closed-form analytical solution proposed by ISO/FDIS 19906 (Arctic offshore structures) is used for comparison. These comparisons indicate that the present numerical model is able to reproduce the ice floe kinematics and impact characteristics during floe–structure interaction. Furthermore, a sensitivity analysis is conducted, aimed at investigating how much the simulated impact force is affected by variations in the pressure–area relationship.

Experimental and Numerical Study of Ballistic Impact Performance on UHMWPE Composites

2013 ◽  
Vol 818 ◽  
pp. 30-36 ◽  
Author(s):  
Yao Ke Wen ◽  
Cheng Xu ◽  
Ai Jun Chen ◽  
Shu Wang
Keyword(s):  
Numerical Model ◽  
Composite Plate ◽  
Numerical Study ◽  
Von Mises Stress ◽  
High Speed Photography ◽  
Numerical Predictions ◽  
Back Face ◽  
Uhmwpe Composites ◽  
The Impact ◽  
Bulge Height

A series of ballistic tests were performed to investigate the bulletproof performance of UHMWPE composites. The temporal evolution of the UHMWPE composite plate back-face bulge height and diameter were captured by high-speed photography. The experiments show the composite plate were perforated when the impact velocity greater than 880m/s. The maximum bulge height and diameter can reach to 3.63-8.23mm and 37-64.5mm at the experimental velocity range , respectively. After that, the numerical model was built with composite material model MAT59 in LS-DYNA and stress based contact failure between plies were adopted to model the delamination mechanism. The number of plies of numerical model shows a strong dependency on the numerical results. Comparisons between numerical predictions and experimental results in terms of bulge height and diameter are presented and discussed. The maximum bulge diameter is good agreement with experiment, but the computational results under predict the maximum bulge height. The computational analysis show the damage development of the plate penetration by the projectile is shearing dominated at first, then the plate undergoes delamination and stretching in the later part of the impact process. The von mises stress at front and back face of the plate were also studied.

Numerical Study of Basalt Fibre Cloth Strengthened Structural Insulated Panel under Windborne Debris Impact

2016 ◽  
Vol 846 ◽  
pp. 446-451 ◽  
Author(s):  
Qing Fei Meng ◽  
Hong Hao ◽  
Wen Su Chen
Keyword(s):  
Numerical Model ◽  
Structural Damage ◽  
Numerical Study ◽  
Building Envelope ◽  
Basalt Fibre ◽  
Structural Wall ◽  
Windborne Debris ◽  
Strong Winds ◽  
The Impact ◽  
Debris Impact

Strong winds happen around the world every year and cause enormous damages and losses. Besides large wind pressure, impact from windborne debris on building envelope is a major source of structural damage in strong winds. The debris lifted and carried by wind impacting on building envelop may create openings on building envelope which increase internal pressure of the building, and lead to roof lifting and even total building collapse. Preventing impact damage to structural wall and roof is therefore critical in extreme wind conditions. On the other hand Structural Insulated Panel (SIP) with Oriented Strand Board (OSB) skins is popularly used in the building industry. Previous studies revealed that such SIP panels had weak impact resistant capacity and do not meet the design requirements to resist windborne debris impact specified in Australian Standard (AS/NZS1170.2:2011) for their applications in cyclonic regions. To increase the capacity of such SIP panels against windborne debris impact, basalt fibre cloth was used to strengthen the panel. Laboratory tests found that SIP strengthened with basalt fibre cloth was effective in increasing its impact-resistant capacity. This paper presents the development of a reliable numerical model to predict the impact responses of basalt fibre cloth strengthened SIP panel in LS-DYNA. The accuracy of the numerical model is verified by comparing the numerical and experimental results. The validated numerical model provides a reliable tool to predict basalt fibre cloth strengthened SIPs.

Evaluation of Wind Loads on FPSO Topsides Using a Numerical Wind Tunnel

2016 ◽  
Author(s):  
Daniel Barcarolo ◽  
Yann Andrillon ◽  
Erwan Jacquin ◽  
Alain Ledoux
Keyword(s):  
Boundary Layer ◽  
Numerical Model ◽  
Wind Tunnel ◽  
Atmospheric Boundary Layer ◽  
Scale Effects ◽  
Geometric Model ◽  
Wind Tunnel Test ◽  
Offshore Structures ◽  
Wind Loads ◽  
The Impact

The accurate evaluation of wind loads applied on floating offshore structures is extremely important as they are in specific conditions one of the dimensioning criteria for the mooring design. Nowadays these loads are mainly assessed through wind tunnel tests performed at model scale. Estimating realistic wind loads however, remains a big challenge. The complexity and associated simplification level of FPSO topside structures, the scale effects and the establishment of the atmospheric boundary layer imply that many simplifications are to be made. Typically, the FPSO topside is greatly simplified and equivalent blocs of wired frame are used. Today with the evolution of CFD software, and the increase of the meshing capacity, new scopes open to CFD. Aerodynamic simulations on complex FPSO structures are therefore now possible, but need specific developments and validations that are presented in this paper. The main objective of the work presented is to investigate the ability of CFD to evaluate wind loads on complex FPSOs topsides and to provide information on the impact of model simplifications made in wind tunnels. In a first stage, the numerical model was intensively validated by comparing its results to a wind tunnel test case. The numerical model was developed in order to ensure the quality of the results and enable a relevant comparison that was obtained with grids density up to 30 million cells. For this purpose, the geometric model used corresponds to the one used in wind tunnel. The same Atmospheric Boundary Layer was simulated and a thorough effort was performed to ensure the mesh convergence. In a second stage, more physical aspects of the wind tunnel methodology were investigated. Typically the accuracy of the blockage effect correction was evaluated by performing computations with and without blockage, and results were compared with classical corrections applied in wind tunnel. The impacts of the Atmospheric Boundary Layer on wind loads have also been investigated. Finally, the wind load contribution of each component of the FPSO was evaluated.

Experimental Investigation of Ice Mass Hydrodynamic Interaction With Offshore Structure in Close Proximity

2015 ◽  
Author(s):  
Tanvir Mehedi Sayeed ◽  
Bruce Colbourne ◽  
Heather Peng ◽  
Benjamin Colbourne ◽  
Don Spencer
Keyword(s):  
Hydrodynamic Interaction ◽  
Impact Load ◽  
Numerical Study ◽  
Numerical Models ◽  
Offshore Structures ◽  
Ocean Engineering ◽  
Offshore Structure ◽  
Area Of Interest ◽  
Close Proximity ◽  
The Impact

Iceberg/bergy bit impact load with fixed and floating offshore structures and supply ships is an important design consideration in ice-prone regions. Studies tend to divide the iceberg impact problem into phases from far field to contact. This results in a tendency to over simplify the final crucial stage where the structure is impacted. The authors have identified knowledge gaps and their influence on the analysis and prediction of iceberg impact velocities and loads (Sayeed et. al (2014)). The experimental and numerical study of viscous dominated very near field region is the main area of interest. This paper reports preliminary results of physical model tests conducted at Ocean Engineering Research Center (OERC) to investigate hydrodynamic interaction between ice masses and fixed offshore structure in close proximity. The objective was to perform a systematic study from simple to complex phenomena which will be a support base for the development of subsequent numerical models. The results demonstrated that hydrodynamic proximity and wave reflection effects do significantly influence the impact velocities at which ice masses approach to large structures. The effect is more pronounced for smaller ice masses.

Numerical Modeling of Turbulent Flow and Heat Transfer Within a Bayonet Tube

2007 ◽  
Author(s):  
Feng Sun ◽  
G.-X. Wang
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Experimental Result ◽  
Working Fluid ◽  
Transfer Performance ◽  
Flow And Heat Transfer ◽  
Air Jet ◽  
The Impact

This paper presents a numerical study of turbulent flow and heat transfer in a bayonet tube under steady state. First, various turbulent models and wall treatment methods have been tested and validated against the experimental result from a turbulent air jet. The proper combination of turbulent model and wall treatment is then recommended for the turbulent flow within a bayonet tube. The study focuses on the heat transfer performance at the interface of working fluid and the outer tube wall under different Reynolds numbers. Various geometry parameters are considered in this work and the impact of geometry on the heat transfer performance is investigated. Results indicate that the heat transfer at the bottom of the bayonet tube is enhanced compared with that at the straight part. At low Re (< 8000), the maximum Nu occurs at the stagnation point, while the position of the maximum Nu moves away from the stagnant point as Re exceeds 8000. The results are believed to be helpful for the optimized design of a bayonet tube with fully turbulent flows.

scholarly journals Experimental and numerical study of wavy mechanical face seals operating under pressure inversions

2019 ◽  
Vol 234 (2) ◽  
pp. 247-260 ◽  
Author(s):  
Jérémy Cochain ◽  
Noël Brunetière ◽  
Andrew Parry ◽  
Henri Denoix ◽  
Abdelghani Maoui
Keyword(s):  
Numerical Model ◽  
Numerical Study ◽  
Hydrodynamic Pressure ◽  
Poor Performance ◽  
Force Balance ◽  
Face Seal ◽  
Spring Force ◽  
Face Seals ◽  
The Face ◽  
The Impact

This paper investigates the impact of the face waviness and pressure inversions on the leakage and on the outer fluid entry of mechanical face seals using a numerical model and an experimental setup. The numerical model couples a transient Reynolds equation, an analytical contact model, a force balance solver, and a solver for the thermo-mechanical deformations. The experimental tests on a face seal with low waviness and on a face seal with high waviness provide leakage and outer fluid entry data, which are reproduced by the model. Contrary to the face seal with low waviness, the face seal with high waviness has poor performance and the pressure inversions increase significantly the ingression of outer fluid. The parametric study shows a decrease of leakage with increasing spring force, and an increase of leakage and outer fluid entry with increasing values of waviness amplitude. The higher leakage observed for wavy seals is shown to be due to the higher average film thickness, and to some extent due to the mechanisms associated with waviness: hydrodynamic pressure generation, film squeeze and stretching.

Numerical study of the melting and resolidification of the substrate during the impact of a ceramic droplet in a plasma spraying process

2019 ◽  
Vol 88 (2) ◽  
pp. 20901 ◽  
Author(s):  
Mouloud Driouche ◽  
Tahar Rezoug ◽  
Mohammed El Ganaoui
Keyword(s):  
Numerical Model ◽  
Phase Change ◽  
Solid Phase ◽  
Numerical Study ◽  
Solid Substrate ◽  
Navier Stokes ◽  
Droplet Spreading ◽  
Substrate Melting ◽  
Volume Method ◽  
The Impact

The substrate melting can significantly improve the properties of plasma spray coatings. Indeed the adhesion of the projected particles to the substrate can be ameliorated by the substrate melting. In this article, a numerical model is developed to study the dynamics of fluids and heat transfer with liquid/solid phase change during impact of a fully melted alumina particle on an aluminum solid substrate, taking into account of the substrate melting. The model is based on solving the Navier-Stokes and energy equations with liquid / solid phase change. These equations are coupled with the fluid of volume method (VOF), to follow the free surface of the particle during its spreading and solidification. The finite volume method is used to discretize the equations in a 2D axisymmetric domain. A comparison with the published experimental results was carried out to validate this numerical model. Simulations were performed for different initial droplet diameters to study its effect on droplet spreading as well as on substrate melting. It has been observed that the substrate melting begins before the droplet spreads completely; the substrate melting reaches its maximum when the droplet is close to its total solidification. Droplet spreading and substrate melting are more important for large sizes droplets.

A CFD Investigation on the Effect of the Air Entrainment in Breaking Wave Impacts on a Mono-Pile

2017 ◽  
Author(s):  
Pietro D. Tomaselli ◽  
Erik Damgaard Christensen
Keyword(s):  
Experimental Investigation ◽  
Circular Cylinder ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Breaking Wave ◽  
Line Force ◽  
Entrainment Process ◽  
The Impact

In impacts of breaking waves on offshore structures, it is still not well-known how the air entrainment phenomenon affects the exerted loads. In this paper, a developed CFD solver capable of simulating the air entrainment process was employed to reproduce an experimental investigation on the impact of a spilling wave against a circular cylinder. The exerted in-line force was computed with and without the inclusion of dispersed bubbles. Results showed that the magnitude of the computed force was affected when the entrainment of bubbles was simulated.

A Numerical Study of Uplift Motion of Flat-Bottom Cylindrical Shell Model Tank Subjected to Harmonic Excitation

2010 ◽  
Author(s):  
Teruhiro Nakashima ◽  
Tomoyo Taniguchi
Keyword(s):  
Cylindrical Shell ◽  
Numerical Study ◽  
Harmonic Excitation ◽  
Fe Analysis ◽  
Experimental Result ◽  
Bottom Plate ◽  
Flat Bottom ◽  
Tank Model ◽  
Rocking Motion ◽  
The Impact

In analyzing the rocking motion of unanchored flat-bottom cylindrical shell tanks, the fluid-structure interaction and the impact between the tank bottom plate and tank foundation should be treated adequately. Employing harmonic excitation, this paper examines the applicability of the explicit FE-Analysis technique for analyzing the rocking motion of a flat-bottom cylindrical shell tank model. Since the tank model possesses a thick and elastic bottom plate, the model tank pivots upon from an edge of the bottom plate to another edge of that reciprocally. The rocking motion of the model tank to the harmonic excitation is numerically computed and the uplift displacement of the tank is compared with experimental result. Agreement between the numerical and experimental results implies that the explicit FE-Analysis is capable of analyzing the rocking motion of cylindrical shell tanks subjected to the earthquake excitation.

Iceberg Impact Simulation on Offshore Structures

2017 ◽  
Author(s):  
Marc Cahay ◽  
Brian A. Roberts ◽  
Kenton Pike ◽  
Pierre-Antoine Béal ◽  
Cyril Septseault ◽  
...  
Keyword(s):  
Impact Load ◽  
Development Program ◽  
Offshore Structures ◽  
Separation Distance ◽  
Offshore Structure ◽  
Pressure Area ◽  
Common Framework ◽  
Multi Agent ◽  
Crushing Behavior ◽  
The Impact

In 2012 TechnipFMC, Cervval and Bureau Veritas initiated a common development program to offer a new tool for the design of offshore structures interacting with ice combining a variety of models and approaches. This numerical tool called Ice-MAS (www.ice-mas.com) is using a multi-agent technology and has the possibility to combine in a common framework multiple phenomena from various natures and heterogeneous scales (i.e. drag, friction, ice-sheet bending failure, local crushing and rubble stack up). The current development phase consists of the determination of the forces generated by an iceberg during an impact on an offshore structure. This paper will provide an overview of the latest Ice-MAS development. It will introduce the main functionalities of the simulation tool and the different options for modelling an offshore structure. It will then focus on the modelling approach used for an iceberg, the calculation of the different hydrodynamic coefficients and their variability according to the separation distance from the structure. The model used to compute the impact load will be detailed, including the local crushing behavior which is simulated by a pressure-area correlation.

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