Numerical Simulation on Wave Interference of Catamaran with Fin Stabilizer

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Arifah Ali ◽  
Adi Maimun ◽  
Yasser M. Ahmed
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Flow Pattern ◽  
Cfd Simulation ◽  
Surface Effect ◽  
Wave Pattern ◽  
Surface Flow ◽  
Water Condition ◽  
Wave Interference ◽  
Fin Stabilizer

Generated wave pattern of twin hull ship is important in analyzing wave interference between hulls. As each hull will generate own wave pattern, which might be identical for both hulls, the interference of wave generated can be either amplification or reduction factor for wave making resistance of the twin hull ship. Free Surface Flow is important to be considered in wave making resistance analysis of twin hull including hull with fin stabilizer, especially for ship operates in shallow water condition. Computational analysis using Computational Fluid Dynamics (CFD) simulation is performed using Reynolds Average Navier-Stokes (RANS) to solve free surface effect problem. The method which applied is Volume of Fluid method, considering two phase condition. The objective of simulation is to predict the wave making resistance and flow pattern of catamaran with and without fin stabilizer, considering the relationship between wave interference and fins stabilizer. The analysis is performed in two configurations, bare hulls and hulls attached with fins. For both configurations, the investigation was conducted with range of model speed from 10 to 20 knots using k-epsilon turbulence model in shallow water condition. The results were based on pressure resistance (Rp) and flow pattern around hulls.

A layer-integrated approach for shallow water free-surface flow computation

2007 ◽  
Vol 24 (12) ◽  
pp. 1699-1722
Author(s):  
Meng-Chi Hung ◽  
Te-Yung Hsieh ◽  
Tung-Lin Tsai ◽  
Jinn-Chuang Yang
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Free Surface Flow ◽  
Integrated Approach ◽  
Surface Flow ◽  
Flow Computation

The Free Surface Flow Around a TLP

2010 ◽  
Author(s):  
A. Yalpaniyan ◽  
M. Goodarzi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Turbulent Flow ◽  
Numerical Solution ◽  
Flow Pattern ◽  
Symmetry Plane ◽  
Free Surface Flow ◽  
Inviscid Flow ◽  
Surface Flow ◽  
Wave Heights

A TLP is a buoyant platform containing four cylindrical columns. The purpose of this study was to consider the effects of different model solvers in the numerical solution on the flow pattern around the TLP. The flow around the TLP was numerically simulated with inviscid, laminar, and turbulent solvers. Three Froude numbers were run for each case. There was a symmetry plane that allowed simulating just one half of the flow field. Therefore, two columns along the symmetry plane were considered in the results discussion. Beside the generated surface waves there was a pair of vortex behind each column none of them were actually symmetric. The vortex behind the first column significantly affected the flow pattern around the second one in the manner that the vortex behind the first column was larger than the next one. In all cases the outer vortex was larger than the inner one. The obtained results showed that the generated waves of the inviscid flow were smoother than the turbulent flow, and also those of the turbulent flow were smoother than the laminar ones. Compared to the mentioned results, the influence of the flow velocity on the wave heights was more significant.

RANS Simulation of the Flow Around a Ship Advancing in Shallow Water

2020 ◽  
Author(s):  
Yan-Yun Zhang ◽  
Zao-Jian Zou ◽  
Jian-Xi Yao
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Grid Method ◽  
Wave Pattern ◽  
Resistance Coefficient ◽  
Water Condition ◽  
Calm Water ◽  
Wigley Hull ◽  
Overset Grid Method ◽  
Sinkage And Trim

Abstract This paper simulates the viscous flow about a ship advancing in calm water of different water depths using Reynolds-Averaged Naiver-Stokes (RANS) method. A Wigley hull is taken as the study object, and the hull is free in sinkage and trim in the simulations. The fluid domain is discretized into hexahedral structured grids. The overset grid method and the deforming grid method are applied in different cases to capture the ship’s sinkage and trim motion. The grid independence analysis and validation of numerical method are carried out under deep water condition. Then, systematic simulations are carried out under shallow water condition at different ship speeds. The resistance performance and the wave pattern characteristics are compared with deep water condition to demonstrate the shallow water effect. Furthermore, resistance coefficient results under water depth-to-draft ratios of 2.0 and 1.5 are presented and compared. All simulations show great consistency with the theoretical and other potential theory based numerical results.

Multiphase modeling of the free surface flow through a Darrieus horizontal axis shallow-water turbine

2019 ◽  
Vol 143 ◽  
pp. 1890-1901 ◽  
Author(s):  
Alla Eddine Benchikh Le Hocine ◽  
R.W. Jay Lacey ◽  
Sébastien Poncet
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Horizontal Axis ◽  
Multiphase Modeling ◽  
Water Turbine ◽  
Flow Through

Adaptive Grid Refinement for Free-Surface Flow Simulations in Offshore Applications

2015 ◽  
Author(s):  
Peter van der Plas ◽  
Arthur E. P. Veldman ◽  
Henri J. L. van der Heiden ◽  
Roel Luppes
Keyword(s):  
Free Surface ◽  
Moving Objects ◽  
Cfd Simulation ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Adaptive Refinement ◽  
Efficiency Gain ◽  
Grid Refinement ◽  
Wave Impact ◽  
Area Of Interest

In many (wave) impact problems the area of interest does not change in time and is readily pointed out by hand, allowing for a one-time design of an efficient computational grid. However, for a large number of other applications, e.g. involving violent free-surface motion or moving objects, a reasonable efficiency gain can only be obtained by means of time-adaptive refinement of the grid. In previous studies a fixed, block-based Cartesian local grid refinement method was developed and implemented in the CFD simulation tool ComFLOW [1], a VOF-based Navier-Stokes solver on Cartesian grids with cut-cell discretization of the geometry. Special attention was paid to the interface discretization in cut-cells as well as the fluid displacement algorithm across refinement boundaries. The method was successfully applied to a range of offshore applications, including for example wave-impact on a semi-submersible (figure 1)and sloshing in a moonpool. In the present paper we present the first results of our attempts to extend the method to support adaptive refinement.

Meshless method for shallow water equations with free surface flow

2011 ◽  
Vol 217 (11) ◽  
pp. 5113-5124 ◽  
Author(s):  
M. Darbani ◽  
A. Ouahsine ◽  
P. Villon ◽  
H. Naceur ◽  
H. Smaoui
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Shallow Water Equations ◽  
Meshless Method ◽  
Free Surface Flow ◽  
Surface Flow

Numerical Simulations of Two Back-To-Back Horizontal Axis Tidal Stream Turbines in Free-Surface Flows

2020 ◽  
Vol 87 (6) ◽  
Author(s):  
Jinhui Yan ◽  
Xiaowei Deng ◽  
Fei Xu ◽  
Songzhe Xu ◽  
Qiming Zhu
Keyword(s):  
Free Surface ◽  
Surface Effect ◽  
Mathematical Formulation ◽  
Time History ◽  
Free Surface Flow ◽  
Free Surface Flows ◽  
Surface Flow ◽  
Wake Effect ◽  
Tidal Turbine ◽  
Tidal Stream

Abstract We simulate two back-to-back full-scale tidal turbines using an in-house computational free-surface flow code. We briefly present the mathematical formulation of the computational framework. We first validate the proposed method on a single turbine configuration. A mesh refinement study is conducted to ensure the result is converged. We then quantify the wake effect and free-surface effect on tidal turbine performance by a case study. To investigate the free-surface effect, we perform both pure hydrodynamics and free-surface simulations. The time history of thrust and production coefficients is quantified. In both pure hydrodynamics and free-surface flow simulations, thrust and production coefficients of the downstream turbines drop significantly due to the velocity deficit in the wake. By comparing the result between free-surface flow and pure hydrodynamics simulations for the configuration considered here, we find that the free-surface does not affect the upstream turbine but significantly affects the downstream turbine.

scholarly journals PREDICTION OF FREE SURFACE FLOW ON CONTAINMENT FLOOR USING A SHALLOW WATER EQUATION SOLVER

2009 ◽  
Vol 41 (8) ◽  
pp. 1045-1052
Author(s):  
Young-Seok Bang ◽  
Gil-Soo Lee ◽  
Byung-Gil Huh ◽  
Deog-Yeon Oh ◽  
Sweng-Woong Woo
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Shallow Water Equation ◽  
Free Surface Flow ◽  
Surface Flow
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