Title: Self-Propulsion RANS Computations with a Single-Screw Container Ship
Abstract: This paper presents the results of CFD simulations with the benchmark container ship MOERI KCS, using the two approaches - a coupled viscous/potential method that involves iterative solution done with RANS and panel method, and a fully unsteady RANS method where the free surface effects are accounted approximately. Putting the main focus on CFD validation against the experimental data and comparison between the methods, in the present study we address model scale conditions. While at the early design stages one has to rely on systematic experience, empirical methods or conduct model tests to do ship performance prediction, it is now becoming more and more common to involve CFD methods for the final check of the design and for solving optimization problems where alterations in hull and propeller designs are required. CFD methods allow for the simulation of the whole system ship-propulsor including all significant mechanisms that influence its performance such as turbulence, free surface, interaction effects and cavitation. These methods can be applied directly to full scale, and they can be used in scale effect studies. In the present paper we discuss the results obtained with the two numerical approaches to the analysis of ship and propeller under self-propulsion condition. The first approach is referred as the iterative viscous/potential coupled method, since it implies an iterative solution where a RANS method is employed to solve the viscous flow around ship hull, and a panel method is employed to solve the potential flow around propeller. The two aforementioned solutions are linked through an actuator disk model that represents propeller effect in the RANS solution. The second approach is referred as the fully unsteady RANS method, since it solves directly the viscous flow around ship hull and propeller, where unsteady interaction between the stationary and rotating parts of the flow is resolved by the sliding mesh technique. In the first method, the free surface effects are modelled directly, while in the second method the free surface is not modelled, but the effect of wave making on ship resistance is accounted for approximately, based on the results of towing simulations. Due to the simplifications made both methods are suitable for engineering calculations as they require moderate computer resources. For the validation studies, the case of the MOERI KCS container ship is chosen. This case represents one of the most complete experimental datasets regarding hull-propeller interaction, and it is repeatedly used in CFD validation studies (Larsson et al. 2010). The detailed results of validation and verification studies with the methods of choice have been described in one of the earlier papers by the author (Krasilnikov, 2012), and herewith we will only present their main findings, while the main focus will be put on the comparison at self-propulsion condition. 2 CHOICE OF THE METHODS
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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Cited By Count: 17
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