Prediction of wave resistance by a Reynolds-averaged Navier-Stokes equation–based computational fluid dynamic approach (original) (raw)
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Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment, 2015
The prediction of wave resistance in naval architecture is an important aspect especially at high Froude numbers where a great percentage of total resistance of ships and submerged bodies is caused by waves. In addition, during hull form optimization, wave resistance characteristics of a ship must closely be observed. There are potential, viscous and experimental methods to determine the wave resistance of a ship. Reynolds-averaged Navier–Stokes equation–based methods usually follow the experimental method that determines the form factor first. However, it is proven in recent studies that the form factor changes with the Reynolds number. As the Reynolds number increases, this change in the form factor is being neglected. In this study, a Reynolds-averaged Navier–Stokes equation–based prediction of wave resistance is presented that overcomes this flaw. The methodology is validated with the benchmark problems of submerged and surface-piercing bodies to determine the effectiveness of t...
Journal of Applied Mathematics, 2012
This paper describes the development of alternative time domain numerical simulation methods for predicting large amplitude motions of ships and floating structures in response to incoming waves in the frame of potential theory. The developed alternative set of time domain methods simulate the hydrodynamic forces acting on ships advancing in waves with constant speed. For motions' simulation, the diffraction forces and radiation forces are calculated up to the mean wetted surface, while the Froude-Krylov forces and hydrostatic restoring forces are calculated up to the undisturbed incident wave surface in case of large incident wave amplitude. This enables the study of the above waterline hull form effect. Characteristic case studies on simulating the hydrodynamic forces and motions of standard type of ships have been conducted for validation purpose. Good agreement with other numerical codes and experimental data has been observed. Furthermore, the added resistance of ships in waves can be calculated by the presented methods. This capability supports the increased demand of this type of tools for the proper selection of engine/propulsion systems accounting for ship's performance in realistic sea conditions, or when optimizing ship's sailing route for minimum fuel consumption and toxic gas emissions.
Numerical study of viscous wave-making resistance of ship navigation in still water
Journal of Marine Science and Application, 2014
The prediction of a ship's resistance especially the viscous wave-making resistance is an important issue in CFD applications. In this paper, the resistances of six ships from hull 1 to hull 6 with different hull forms advancing in still water are numerically studied using the solver naoe-FOAM-SJTU, which was developed based on the open source code package OpenFOAM. Different components of the resistances are computed and compared while considering two speed conditions (12 kn and 16 kn). The resistance of hull 3 is the smallest while that of hull 5 is the largest at the same speed. The results show hull 3 is a good reference for the design of similar ships, which can provide some valuable guidelines for hull form optimization.
Maneuverability and resistance prediction with suitable accuracy is essential for optimum ship design and propulsion power prediction. This paper aims at providing some of the resistance and maneuverability characteristics of a container ship model, MOERI KCS in calm water using a computational fluid dynamics solver named Ship Motion. The solver is based on the Reynolds average Navier-Stokes method (RaNS) and solves overset-structured grid using the Finite Volume Method (FVM). This paper comprises the numerical results of calm water test for the KCS model with available experimental results. The calm water test results include the total drag coefficient, average sinkage, and trim data. Visualization data for pressure distribution on the hull surface and free water surface have also been included. The paper concludes that the present solver has the capability to predict the resistance and maneuverability characteristics of the container ship with reasonable accuracy utilizing minimum computational resources.
Numerical Prediction of the Vertical Responses of Planing Hulls in Regular Head Waves
Journal of Marine Science and Engineering
The evaluation of the hydrodynamic performance of planing vessels has always been one of the most attractive study fields in the maritime agenda. Resistance and self-propulsion studies have been performed using experimental and numerical methods by researchers for a long time. As opposed to this, the seakeeping performance of planing hulls is assessed with 2D approximation methods, but limitedly, while the experimental campaign is not cost-effective for several reasons. With this motivation, pitch and heave transfer functions and accelerations were obtained for a monohedral hull and a warped hull using a state of art commercial Reynolds-averaged Navier–Stokes (RANS) solver, in this study. Moreover, 2-DOF (degree of freedom) dynamic fluid–body interaction (DFBI) equations were solved in a coupled manner with an overset mesh algorithm, to find the instantaneous motion of the body. After verification, obtained numerical results at three different Froude numbers and a sufficiently large...
Prediction of added resistance of ships in waves
The prediction of the added resistance of ships in waves is a demanding, quasi-second-order seakeeping problem of high practical interest. In the present paper, a well established frequency domain 3D panel method and a new hybrid time domain Rankine source-Green function method of NTUA-SDL are used to solve the basic seakeeping problem and to calculate first order velocity potentials and the Kochin functions, as necessary for the calculation of the added resistance by Maruo's far-field method. A wide range of case studies for different hull forms (slender and bulky) was used to validate the applicability and accuracy of the implemented methods in practice and important conclusions regarding the efficiency of the investigated methods are drawn.
ON THE FOREBODY SHAPE EFFECT ON SHIP RESISTANCE IN STILL WATER AND SEAWAY
Proc. of 14th Int. Conf. on Marine Sciences and Technologies (Black Sea 2018), 2018
In recent years CFD technologies are actively used for the practice in the design and optimization of the ship hull form. The suggested method of in-detail hull form design uses CFD for hull resistance determination. The obtained results can be presented as the optimum distribution of the required hull volume and, eventually, the optimized shape of hull surface. The method was applied to forebody of the well-known KCS hull form and showed interesting characteristics. This paper describes farther development of the method as well as diversified analysis of its reliability and practical feasibility. It is shown that precision can be noticeably improved, however correctness strongly depends on CFD model and computational grid. At last, it has been taken into account that the optimization process manages hull resistance in still water only. Therefore the overall design assessment of the optimized forebody shape is supported by estimation of resistance in seaway.
THEORETICAL SHIP WAVE PATTERN RESISTANCE EVALUATION USING KOCHIN WAVE AMPLITUDE FUNCTION
International conference cum exhibition: Tech Samudra, IMU, Dec 2012., 2012
Ship wave pattern resistance evaluation has been an important event in the optimization process of variety of hull forms ranging from small crafts to fast displacement hull forms including multihull vessels. Several experimental methods for wave pattern analysis like Hogben Matrix Element Method (MEM), Longitudinal & transverse wave cuts involving Landweber Fourier Transform (LFT) and Matrix solution method, theoretical methods like Michell's thin ship theory, Rankine source-sink and Kochin-Fourier method exist today with their merits and limitations. Ship wave pattern resistance is mostly a derived quantity from experiments either as a subset of residuary resistance or when total viscous component is known. In general applying Froude's hypothesis, the residuary resistance coefficient is not subjected to scaling effects from model to prototype and evaluation of total viscous component for surface ships by model experiments is seldom done. Optimization of hull forms through wave pattern studies is a powerful tool and in-house potential flow solvers/experimental evaluation techniques for free surface flows have been developed in many hydrodynamic test facilities. The present paper focuses on ship wave pattern evaluation using Michell's theory (using Kochin wave amplitude function) and its comparison with Shipflow ® & Longitudinal wave cut method (using LFT) on bench mark test model R/V Athena. Matlab ® code development and ship wave pattern resistance evaluation sensitivity for the method chosen is also a part of present discussion.
International Journal of Engineering Systems Modelling and Simulation, 2018
In recent years, a great deal of research effort on ship hydrodynamics is devoted to practical navigation problems in moving planing vessels safety. The purpose of this study is to investigate the added resistance of DTMB 62 model 4667-1 planing hull using a CFD software based on the finite volume method to solve the RANS equations in different Fr numbers in head waves. In addition, the wave profile and wave pattern on the hull of the vessel is investigated. For this purpose, a finite volume ANSYS-FLUENT code is used to solve the Navier-Stokes equations for simulating the flow field around the vessel. In addition, an explicit VOF scheme and k-ε model is used to capture the interface and to model the turbulence respectively. The results show that increasing the Froude number, increases the added resistance of a planing vessel in regular waves.