8/3/2019 Analisis Kinerja Kapal Selam Autonomous Menggunakan Cmputational Fluid Dynamics_Marine Transport_Phillips_Ale…

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HULL PROPELLER RUDDER 

INTERACTION

The propeller accelerates the flow at the rear of the vesselmodifying the flow around the hull and any control surfaces.Thus to accurately model the in service performance of the  vehicle the propulsion system must be included in thecalculations.

Explicit transient calculation of the propeller is possible inRANS simulations but is computationally expensive. A suitable representation of the mean flow can be achieved by coupling the RANS simulation with an external Blade

Element Momentum (BEM) code. The inflow into thepropeller disc is extracted from the RANS simulation andinput into the BEM code which calculates the resultant thrustand torque at a specified rpm. The thrust and torque are thenimplemented as momentum sources within the RANSsimulation. This two way coupling allows good prediction of the global forces and moments acting on the vessel

BACKGROUND

This research aims to develop a methodology capable of assessing various aspects of the resistance andmanoeuvrability of AUVs using steady and unsteady CFDanalysis methods, which balance the trade-off betweencomputational cost and fluid dynamic fidelity. The resultsof which can be fed into the hull design of the vehicle, itscontrol and propulsion systems and the missions itundertakes.

This research will concentrate on running modestcomputational meshes with the commercial CFD code ANSYS CFX 11. This work concentrates on two aspects:-

-Identifying the key components of the flow around amanoeuvring submarine and ensuring these features arefully resolved.

-Investigating the interaction of the hull propeller andrudders.

Performance Analysis of Autonomous Underwater Vehicles

Using Computational Fluid Dynamics Alexander Phillips - abp@soton.ac.uk - School of Engineering Sciences

Supervisors – Dr. S.R. Turnock and Dr. M. Furlong (NOC)

DELPHIN AUV 

Is the successor to the successful SotonAUV, which won theStudent Autonomous Underwater Challenge – Europe 2007.The vehicle was built by 4th  year GDP students, and is now operated by a team of post graduate students who use as atest bed for analysing the manoeuvrability of small AUVs,and to provide validation data for numerical models.

FLOW FEATUR E IDENTIFICATION

Discrepancies between CFD simulations and experimentalresults for the forces and moments on a manoeuvring AUV or submarine, observed in this work and by a series of authors, Lee et al.(2005b), Wu et al. (2005), Bellevre et al.(2000) are beloved to be largely a function of poor

resolution of hull vortices developed around the hull whenoperating at an angle of attack.

Extensions to the VORTFIND algorithm, Pemberton et al.(2002), and the WakeFind Algorithm, Pashius (2005), areproposed to locate the centre of the vortex and centre of the wake structure downstream.

Figure 1 :- Recovering Autosub 

Figure 2 :- Automated identification of the extent of the vortex core and wake downstream of a rudder 

Figure 3 :- Streamlines representing the flow around Autosub 3 

Figure 4 :- DELPHIN AUV