Numerical Hull Resistance and Hydrodynamic Characteristics of an Independently Rotating Multi-Hull Vessel

2019 ◽  
Author(s):  
Sharath Srinivasamurthy ◽  
Hiroshi Sakamoto ◽  
Tatsuo Nishikawa ◽  
Yasunori Nihei
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
Cfd Simulation ◽  
Hydrodynamic Characteristics ◽  
Cfd Simulations ◽  
Basic Framework ◽  
Wave Patterns ◽  
Experimental Findings ◽  
Hydrodynamic Effects ◽  
Simulation Scheme

Abstract In this study, an attempt is made to understand the hydrodynamic characteristics of an automated multi-hull vessel named as Quadmaran. Firstly, a single hull of the Quadmaran vessel is considered and numerical CFD simulation is performed using OpenFOAM. Hull resistance predictions are compared with the experimental findings and numerical simulation is validated. After validating the simulation scheme, further CFD simulations are performed on two hulls with varying distance between them to understand the hydrodynamic characteristics of different configurations. Pressure distribution and wave patterns around the hulls are also summarized and discussed in the paper. Further, efforts are made to optimize the distance between the hulls for reducing hull resistance. A basic framework is suggested to carefully consider the hydrodynamic effects for multi-hull vessels.

Aerodynamic Degradation of Iced Airfoils: Experiments and CFD Simulations

2009 ◽  
Author(s):  
Z. Chara ◽  
V. Horak ◽  
D. Rozehnal
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Cfd Simulation ◽  
Panel Method ◽  
Ice Accretion ◽  
Cfd Simulations ◽  
Ansys Cfx ◽  
Lift And Drag ◽  
Naca 0012 ◽  
Ice Shapes

The phenomenon of in-flight icing may affect all types of aircraft. Presence of ice on wings can lead to a number of aerodynamic degradation problems. Thus, it is important to understand the different ice shapes that can form on the wings and how they affect aerodynamics. When compared to wings without ice, wings with ice indicate decreased maximum lift, increased drag, changes in pressure distribution, stall occurring at much lower angles of attack, increased stall speed, and reduced controllability. The in-house ice accretion prediction code R-ICE using 2-D panel method was developed. The CFD simulation with the software ANSYS CFX 11.0 was used to simulate flow around iced airfoils NACA 0012. These airfoils were experimentally investigated in a wind tunnel. The paper presents a comparison of lift and drag coefficients experimentally observed and numerically simulated.

Sensitivity of Reduced Kinetic Models: The CFD Simulation of SCO2 Oxy-Combustion

2018 ◽  
Author(s):  
Zefang Liu ◽  
Xiang Gao ◽  
Miad Karimi ◽  
Bradley Ochs ◽  
Vishal Acharya ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Kinetic Model ◽  
Kinetic Models ◽  
Equivalence Ratio ◽  
Cfd Simulation ◽  
Selection Algorithm ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Jet In Crossflow ◽  
Autoignition Delay

Current research on supercritical carbon dioxide (SCO2) oxy-combustion is lacking studies on the performance of kinetic models. An optimized 13 species kinetic model is proposed in the present work for CH4/O2/CO2 oxy-combustion. This 13 species kinetic model is developed based on the detailed USC Mech II mechanism with the Global Pathway Selection algorithm, and then optimized with a genetic algorithm covering conditions of pressure from 150 atm to 300 atm, temperature from 900 K to 1800 K and equivalence ratio from 0.7 to 1.3. The autoignition of 13 species kinetic model presents less than 12% error relative to that of the USC Mech II. The performance of the proposed kinetic model is evaluated using a generic jet in crossflow combustor. Simulations at identical conditions are conducted in ANSYS Fluent for both the 13 species model and a global 5 species model. Results were then compared to evaluate the sensitivity of these two kinetic models to the CFD simulations. The results show a better mixing between the fuel and the oxygen, a longer autoignition delay and a more reasonable temperature distribution using the 13 species kinetic model. It is indicating the importance of choice on kinetic models in numerical simulation.

Wind Tunnel Experiment and Numerical Simulation of the Pressure Distribution on a Sedan Exterior Surface

2013 ◽  
Vol 300-301 ◽  
pp. 1027-1031
Author(s):  
Bo Yang ◽  
Li Na Huang ◽  
De Jiu Wu ◽  
Xing Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Cfd Simulation ◽  
Wind Tunnel Experiment ◽  
Aerodynamic Noise ◽  
Computational Domain ◽  
Side View ◽  
Side Window ◽  
Near Wall

The wind tunnel measurement and numerical simulation of a 50% scaled sedan model surface pressure distribution were made in order to provide fundamental data for improving the Computational Fluid Dynamics (CFD) simulation accuracy of the aerodynamic noise related flow field around automobiles. The pressure measurement positions of the wind tunnel experiment were on the side window and the door. The wind tunnel test section speed was 30m/s at 0° yawing angle. As for the CFD simulation, the wind tunnel shape computational domain and four settings of the near wall computational mesh were made. Both the k-ω SST and the Realizable k-ε turbulence models were chosen. And three value ranges of the near wall computational mesh’s dimensionless wall distance (y+) were realized. Compared with the experimental data, the pressure coefficient (CP) simulation results showed good agreement with the measurement at the re-attaching region on the side window and the attaching region on the door. But the large CPprediction errors happened in the region of the front pillar vortex, the side view mirror wake. It was also shown that the predicted CPvalues were almost independent of the y+value, except the comparatively larger CPpredicted errors on the side window obtained by using the k-ω SST turbulent model when the y+value ranged from 4 to 7. Further unsteady CFD simulation and the exterior aerodynamic noise measurement need be carried out due to the unsteady features of the separated flows, including the front pillar vortex and the side view mirror wake.

scholarly journals Simulation of vertical tidal turbine based on OpenFOAM and influence of inlet turbulence

2019 ◽  
Vol 272 ◽  
pp. 01017
Author(s):  
Liu Yun-ya ◽  
Yu-chen Yang ◽  
Ya-wen Yang
Keyword(s):  
Numerical Simulation ◽  
Turbulence Model ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Simulation Method ◽  
Hydrodynamic Characteristics ◽  
Numerical Simulation Method ◽  
Tidal Turbine ◽  
Cfd Method ◽  
Control Equation

This paper first introduces the basic theory of CFD method, including basic control equations, finite volume method, control equation solving algorithm and turbulence model selection. Second, based on OpenFOAM, an open-source fluid mechanics software, a numerical simulation method of vertical axis tidal turbine was proposed by using k-ω SST turbulence model and PIMPLE algorithm. The hydrodynamic characteristics of the vertical axis turbine were studied, and the calculation results were compared with experiments. The higher consistency proves the feasibility of the numerical simulation method proposed in this paper. Finally, the influence of inlet turbulence on numerical simulation was explored, and a set of effective CFD simulation strategies was concluded, which provided a valuable reference for future CFD simulation and research on vertical axis tidal turbines.

Numerical Simulation of High Velocity Waterjet Characteristics and Impact Pressure

2011 ◽  
Vol 109 ◽  
pp. 551-556 ◽  
Author(s):  
Qun Luo ◽  
Kai He ◽  
He Mao ◽  
Jiu Hua Li ◽  
Quan Chang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
High Velocity ◽  
Impact Pressure ◽  
Hydrodynamic Characteristics ◽  
Initial Region ◽  
Mixture Flow ◽  
Incremental Sheet Metal Forming ◽  
Pump Pressure ◽  
The Impact

This paper presents a numerical simulation approach to analyze high velocity waterjet characteristics and impact pressure. For the complexity of waterjet formation in air, multiphase mixture flow model is used, and the simulation is performed in FLUNET software. The simulation includes the hydrodynamic characteristics and pressure distribution of high velocity waterjet in air. The decay of pressure at different distance along centerline under different pump pressure is analyzed and the length of the initial region of waterjet is determined. In addition, the impact pressure of waterjet at different stand-off distance is also simulated, and the impact pressure distribution and its changing tendency with the stand-off distance are obtained. This paper provides theoretical parameters for waterjet incremental sheet metal forming.

CFD Simulation of Truss Spar Vortex-Induced Motion

2006 ◽  
Author(s):  
Sampath Atluri ◽  
John Halkyard ◽  
Senu Sirnivas
Keyword(s):  
Cfd Simulation ◽  
Turbulence Modeling ◽  
General Purpose ◽  
Scale Model ◽  
Cfd Simulations ◽  
Model Experiments ◽  
Helical Strakes ◽  
Induced Motion ◽  
Truss Spar ◽  
Hydrodynamic Effects

Helical strakes are used to suppress the Vortex-Induced Motion of Truss Spars. Model experiments have demonstrated the efficiency of strakes in the Truss Spar design but also indicate that the VIM response is sensitive to the details of strake design and placement of appurtenances around the Spar hull. It is desirable to study these hydrodynamic effects using CFD. The following paper is a continuation of some of the earlier CFD simulations on this subject (see, J. Halkyard, et al., “Benchmarking of Truss Spar Vortex-Induced Motions Derived from CFD with Experiments”, Proceedings of OMAE’05). This paper in particular deals with the effect of holes in the strakes and appurtenances and their placement. All the simulations were done at model scale (1:40 scale model of an actual Truss Spar design) to compare the motions with experimental results. Mesh sensitivity and turbulence modeling issues are also discussed. Calculations were done using general purpose CFD code Acusolve™.

Numerical Simulation of Tire Sliding Events Involving Impacts with Holes and Bumps

1986 ◽  
Vol 14 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Y. Nakajima ◽  
J. Padovan
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Full Range ◽  
Arbitrary Geometry ◽  
Operating Environments ◽  
Element Simulation ◽  
Simulation Scheme

Abstract This paper extends the finite element simulation scheme to handle the problem of tires undergoing sliding (skidding) impact into obstructions. Since the inertial characteristics are handled by the algorithm developed, the full range of operating environments can be accommodated. This includes the treatment of impacts with holes and bumps of arbitrary geometry.

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

scholarly journals The study of the numerical diffusion in computational calculation

2020 ◽  
Vol 310 ◽  
pp. 00039
Author(s):  
Kamila Kotrasova ◽  
Vladimira Michalcova
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Numerical Simulation ◽  
Continuity Equation ◽  
Cfd Simulation ◽  
Flow Process ◽  
Ansys Fluent ◽  
Numerical Diffusion ◽  
Mesh Density ◽  
Computational Calculation

The numerical simulation of flow process and heat transfer phenomena demands the solution of continuous differential equation and energy-conservation equations coupled with the continuity equation. The choosing of computation parameters in numerical simulation of computation domain have influence on accuracy of obtained results. The choose parameters, as mesh density, mesh type and computation procedures, for the numerical diffusion of computation domain were analysed and compared. The CFD simulation in ANSYS – Fluent was used for numerical simulation of 3D stational temperature flow of the computation domain.

Simulation of Sphere’s Motion Induced by Shock Waves

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Dan Igra ◽  
Ozer Igra ◽  
Lazhar Houas ◽  
Georges Jourdan
Keyword(s):  
Shock Waves ◽  
Drag Coefficient ◽  
Drag Force ◽  
Stationary Flow ◽  
Experimental Results ◽  
Experimental Findings ◽  
Sphere Drag ◽  
Simulation Scheme ◽  
Good Agreement

Simulations of experimental results appearing in Jourdan et al. (2007, “Drag Coefficient of a Sphere in a Non-Stationary Flow: New Results,”Proc. R. Soc. London, Ser. A, 463, pp. 3323–3345) regarding acceleration of a sphere by the postshock flow were conducted in order to find the contribution of the various parameters affecting the sphere drag force. Based on the good agreement found between present simulations and experimental findings, it is concluded that the proposed simulation scheme could safely be used for evaluating the sphere’s motion in the postshock flow.

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