Analysis of Turbulent Flows and VIV of Truss Spar Risers

2006 ◽  
Author(s):  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
Samuel Holmes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulent Flows ◽  
Full Scale ◽  
Complex Flows ◽  
Vortex Induced Vibration ◽  
Complex Problems ◽  
Truss Spar ◽  
Computational Fluid Dynamics Cfd ◽  
Vertical Risers

Complex flows through riser arrays, such as the case of risers located in the truss section of a truss spar, are very difficult to describe and analyze. It is especially difficult predict and correct Vortex Induced Vibration (VIV) response using traditional tools that were meant to analyze single risers rather than arrays of risers. Computational Fluid Dynamics (CFD) offers the designer the capability to properly analyze these complex problems, increasing the reliability of the design. In this study, a full scale truss spar with vertical risers is modeled using CFD. The VIV response of the risers is predicted and the effect of risers is correctly captured and compared with experiments.

VIV Prediction of a Truss Spar Pull-Tube Array Using CFD

2011 ◽  
Author(s):  
Yiannis Constantinides ◽  
Weiwei Yu ◽  
Samuel Holmes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Structural Model ◽  
Full Scale ◽  
Complex Flows ◽  
Single Cylinder ◽  
Structure Interaction ◽  
Cylinder Arrays ◽  
Truss Spar ◽  
Computational Fluid Dynamics Cfd

Complex flows through cylinder arrays, such as the case of pull-tubes located in the truss section of a truss spar, are very difficult to describe and analyze. It is especially difficult to predict and correct Vortex Induced Vibration (VIV) response using traditional tools that were developed to analyze single cylinder rather than arrays of cylinders. Computational Fluid Dynamics (CFD) offers the designer the ability to properly analyze these complex problems and increase the reliability of his design. In this study, a full scale truss spar with pull-tubes is modeled using CFD coupled with an FEA structural model of the pull-tubes for a fluid-structure interaction (FSI) computation. The VIV response of the pull-tubes is predicted and analyzed for different current headings and speeds.

Escort Tug Performance Prediction Using Computational Fluid Dynamics

2016 ◽  
Vol 60 (02) ◽  
pp. 61-77
Author(s):  
Brendan Smoker ◽  
Bart Stockdill ◽  
Peter Oshkai
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Separation ◽  
Travel Speed ◽  
Hydrodynamic Forces ◽  
Full Scale ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Thrust Forces ◽  
Steering Force

In this paper, we outline and validate a computational fluid dynamics (CFD) method for determining the hydrodynamic forces of an escort tug in indirect towing mode. We consider a range of yaw angles from 0° to 90° and a travel speed of 8 knots. We discuss the effects of scaling on prediction of flow separation and hydrodynamic forces acting on the vessel by carrying out CFD studies on both model and full-scale escort tugs performing indirect escort maneuvers. As the escort performance in terms of maximum steering forces is strongly dependent on the onset of flow separation from the hull and skeg of the tug, the model-scale simulations under-predict the maximum steering force by 12% relative to the full-scale simulations. In addition, we provide a method for converting the hydrodynamic forces of the CFD escort study into towline and thrust forces.

Hydrodynamic evaluation of a full-scale facultative pond by computational fluid dynamics (CFD) and field measurements

2014 ◽  
Vol 70 (3) ◽  
pp. 569-575 ◽  
Author(s):  
Ricardo Gomes Passos ◽  
Marcos von Sperling ◽  
Thiago Bressani Ribeiro
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Short Circuit ◽  
Field Measurements ◽  
Tracer Test ◽  
Full Scale ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Hydraulic Behaviour ◽  
Computational Fluid Dynamics Cfd

Knowledge of the hydraulic behaviour is very important in the characterization of a stabilization pond, since pond hydrodynamics plays a fundamental role in treatment efficiency. An advanced hydrodynamics characterization may be achieved by carrying out measurements with tracers, dyes and drogues or using mathematical simulation employing computational fluid dynamics (CFD). The current study involved experimental determinations and mathematical simulations of a full-scale facultative pond in Brazil. A 3D CFD model showed major flow lines, degree of dispersion, dead zones and short circuit regions in the pond. Drogue tracking, wind measurements and dye dispersion were also used in order to obtain information about the actual flow in the pond and as a means of assessing the performance of the CFD model. The drogue, designed and built as part of this research, and which included a geographical positioning system (GPS), presented very satisfactory results. The CFD modelling has proven to be very useful in the evaluation of the hydrodynamic conditions of the facultative pond. A virtual tracer test allowed an estimation of the real mean hydraulic retention time and mixing conditions in the pond. The computational model in CFD corresponded well to what was verified in the field.

Perspective: Future Research Directions in Computational Fluid Dynamics

1994 ◽  
Vol 116 (2) ◽  
pp. 212-215 ◽  
Author(s):  
R. W. Douglass ◽  
J. D. Ramshaw
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Future Research ◽  
Complex Flows ◽  
Research Directions ◽  
Simulation Research ◽  
Current State ◽  
Future Research Directions ◽  
Computational Fluid Dynamics Cfd ◽  
Real Fluids

The current state of computational fluid dynamics (CFD) has yet to reach its full promise as a general tool for engineering design and simulation. Research in the areas of code robustness, complex flows of real fluids, and numerical errors and resolution are proposed as directions aiming toward that goal. We illustrate some of the current CFD challenges using selected applications.

Investigating the effect of sparger configuration on the hydrodynamics of a full-scale membrane bioreactor using computational fluid dynamics

RSC Advances ◽  
2015 ◽  
Vol 5 (127) ◽  
pp. 105218-105226 ◽  
Author(s):  
Ershad Amini ◽  
Mohammad Reza Mehrnia ◽  
Seyyed Mohammad Mousavi ◽  
Hamed Azami ◽  
Navid Mostoufi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Bioreactor ◽  
Cfd Simulation ◽  
Full Scale ◽  
Hydrodynamic Parameters ◽  
Three Phase ◽  
Computational Fluid Dynamics Cfd

A three-phase computational fluid dynamics (CFD) simulation was carried out in a full-scale membrane bioreactor to investigate the effect of sparger configuration on various hydrodynamic parameters.

A CFD Simulation of Strouhal Number for U-Shaped Section Aqueducts

2012 ◽  
Vol 204-208 ◽  
pp. 4738-4741
Author(s):  
Yu Chun Li ◽  
Xiao Jie Zhang ◽  
Shi Wen Jia
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Reynolds Number ◽  
Strouhal Number ◽  
Turbulence Model ◽  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Vortex Induced Vibration ◽  
Computational Fluid Dynamics Cfd ◽  
Shaped Section

The method of computational fluid dynamics (CFD, Fluent code) was applied to simulate the Strouhal numbers of the empty and fulfilled U-shaped sections. Based on the N-S equation and k-ε turbulence model, the effects of Reynolds numbers and height/width ratios of the sections on the Strouhal numbers were investigated. The results of this study show that the Reynolds number has little influence on the Strouhal numbers, which decrease with the increase of height/width ratios of the sections. The conclusion of present study provides a foundation for the further study of vortex-induced vibration of U-shaped aqueduct bridges.

Numerically Modelling the Effect of the Drag Crisis on Vortex Induced Vibration of a Circular Cylinder

2013 ◽  
Author(s):  
Neil Botterill ◽  
Hervé P. Morvan ◽  
John S. Owen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Circular Cylinder ◽  
Normal Flow ◽  
Circular Section ◽  
Vortex Induced Vibration ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Crisis Phenomenon ◽  
Computational Fluid Dynamics Cfd

This paper presents work using commercially available computational fluid dynamics (CFD) software that provides evidence of the effect that the drag crisis has on the dynamic response of a bluff object excited by vortex induced vibration (VIV) from normal flow. Results are presented of simulations of flow past a stationary circular section. A dynamic Large Eddy Simulation (LES) turbulence formulation is used to ensure important features of the drag crisis are captured. Further simulations are presented where the cylinder is free to oscillate in two directions, parallel and normal to the direction of flow. Emphasis is given to the role that the drag crisis phenomenon plays on the locus of oscillations. Key findings are that the drag crisis increases the response by allowing more energy to go into the system on the upstream stroke of the oscillations and that a reversal of drag can occur in both upstream and downstream movements. This suggests the drag crisis phenomenon can affect fatigue performance.

In-Line Motion of Subsea Pipeline Span Models Experiencing Vortex-Shedding

2009 ◽  
Author(s):  
Li Lee ◽  
Don Allen ◽  
Juan P. Pontaza ◽  
Frans Kopp ◽  
Vikas Jhingran
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Vortex Shedding ◽  
Experimental Results ◽  
Ocean Currents ◽  
Velocity Range ◽  
Vortex Induced Vibration ◽  
Subsea Pipeline ◽  
Motion Trajectories ◽  
Computational Fluid Dynamics Cfd

Subsea pipeline spans, when experiencing bottom ocean currents, are prone to vortex-induced vibration (VIV). Experiments and computational fluid dynamics (CFD) are conducted to evaluate the effects of the pipe stiffness on its first mode in-line VIV motion, primarily in the reduced velocity range from approximately 1.0 to 4.0. Experimental results also indicated that there was obliqueness in motion trajectories, which could have impacts on VIV design of the free spans. The main findings of this investigation are presented in this paper.

scholarly journals Interaction Effect between Hull and Accommodation on Wind Drag Acting on a Container Ship

2020 ◽  
Vol 8 (11) ◽  
pp. 930
Author(s):  
Ngo Van He ◽  
Ngo Van Hien ◽  
Van-Thuan Truong ◽  
Ngoc-Tam Bui
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Interaction Effect ◽  
Full Scale ◽  
Ship Hull ◽  
Container Ship ◽  
Drastic Reduction ◽  
Aerodynamic Performances ◽  
Computational Fluid Dynamics Cfd

In this paper, we present our research on applying the commercial Computational Fluid Dynamics (CFD) code to investigate interaction effect between hull and accommodation on wind drag acting above the water hull surface of a full scale 1200 TEU container ship. With this purpose, aerodynamic performances and wind drag acting on the ship hull with and without accommodations have been computed. Analyzing the obtained CFD results, the interaction effect between hull and accommodation on aerodynamic performances and wind drag acting on the ship have been found. Various new accommodation shapes have been proposed for the original ship to reduce the interaction effect on wind drag. A drastic reduction in the interaction effect between hull and accommodation on wind drag acting on the ship has been achieved and the obtained results have been shown in this paper.

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