• Special Issue of the Society of Naval Architects of Korea
• /
• 2008.09a
• /
• pp.62-67
• /
• 2008

The hovercraft is the amphibious hovercraft. Design and manufacturing companies of the aero propeller exist rarely in the world. Hence the propeller has beef designed and manufactured by manufacturing companies which make aero propeller mainly. In this paper, the hovercraft propeller of similar, which is building and designing by HHIC, is considered the type of aero propeller, rotational speed, diameter, number of blades, Open air propeller efficiency. As the result of check, hovercraft which is necessary huge static thrust is needed the ducted propeller in order to improve climbing capacity. However, the number of blades and turning direction almost do not affect.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2002.05a
• /
• pp.129-134
• /
• 2002

This study is focused on the layout design with sizing for the main propulsion shafting with controllable pitch propeller system. For appropriate design and successful manufacturing of controllable pitch Propeller system, it is based on specifications to be required from the customer as well as the stresses calculation and analysis of main propulsion system for hollow shafting. And it must be performed according to the U.S military specifications MIL-STD-2189(SH) with drawing of NAVSHIPS 803-2145807, and also the stress analysis by applying safety factor. The results are as follows : 1. For the main propulsion system with controllable pitch propeller, it is designed the following items propeller diameter, hub diameter, dimensions of oil distribution or actuating unit based on shaft mounting type, diameters of propeller and intermediate shaft, dimension of split muff coupling, coupling flange thickness and of coupling bolt diameter. 2. As the results, we can get complete our own design ability for the main propulsion shafting with controllable pitch propeller system with critical data which are necessary to establish shafting arrangement from the ship building companies.

• Journal of the Society of Naval Architects of Korea
• /
• v.49 no.1
• /
• pp.14-25
• /
• 2012

Recently, the application and installation of the pod propeller to the cruise ship is dramatically increased. It is because pod propulsion system allows a lot of flexibility in design of the internal arrangement of a ship. To reflect this trend, many researches have conducted to use the pod propeller for the roll stabilization of a ship. In the paper, a roll stabilization controller is designed by using fins and pod propellers as the control actuators for cruise ships. Two kinds of control algorithms are adopted for the roll control system; LQR (Linear Quadratic Regulator) algorithm and frequency-weighted LQR algorithm. Through the numerical simulation, the effect of the turning rate of the pod propeller on the roll control system is analyzed. Analysis of the simulation results indicated that the turning rate of the pod propellers is one of the important parameters which give the significant effects on the roll stabilization.

• Journal of the Korean Society of Visualization
• /
• v.5 no.2
• /
• pp.26-32
• /
• 2007

Stereoscopic PTV and Stereoscopic-PIV measurements have been carried out for the studies of the wake of a ship's propeller. Stereoscopic photogrammetry based on a 3D-PTV principle was introduced using two high-definition cameras(1k x 1k, 30Hz). The arrangement of the two cameras was based on angular position. The pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The results obtained by both measurement systems have been compared at the advance ratio J=0.88(290 rpm, d=54 mm). Turbulent properties have also been compared each other at the same condition.

• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.5
• /
• pp.474-481
• /
• 1997

Waterjet propulsion generally refers to propulsion of ships by internally mounted pumps with proper ducting. This arrangement of the actuator component of the system leads to the fundamental differences with respects to screw propeller system. In this paper, the basic hydrodynamic characteristics of waterjet propulsion was outlined to clarify the application consideration and proposal for carrying out model self-propulsion tests with waterjet propelled models was presented. The results of model self-propulsion tests carried out in the Hyundai Maritime Research Institute towing tank with catamaran ship were presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.329-330
• /
• 2008

The 181,000 DWT Bulk Carrier has a different deck house type, which is not typical for previous bulk carriers, to meet the new international rules for bulk carriers. This new deck house has much smaller transverse breadth than the hull's transverse breath, resulting in large levels of the transverse response of the deck house. In addition, the longitudinal response of the funnel showed rather a large magnitude of vibration, which are excited by the ship's main excitations such as the main engine H-moment and the propeller surface forte when the ship operates at the NCR and the MCR speeds In the ballast condition. To solve these issues, the global forced vibration analysis has been performed for the ship and the ship structure has been modified to reduce the vibration level by increasing the girder depth and adjusting the engine room tank arrangement.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3334-3338
• /
• 2012

This work has been performed to evaluate the strength of fixtures, which were attached to outer surface of propeller flask to prevent transient movement during filling and cooling stages at Ni-Al-Bronze casting of large marine propellers. Experimental work was carried out to evaluate forces exerted on flask fixtures by measuring strain changes of fixtures due to thermal expansion and contraction during casting processes. Numerical analyses were also made to verify the experimental results and finally to evaluate the validity of arrangement of flask fixtures for casting of marine propellers.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.4
• /
• pp.361-369
• /
• 2008

The optimized distance between skegs and angle of the skeg for a standard twin-skeg type LNG carrier were presented using the CFD and model tests. The evaluation method of self-propulsion performance was derived based on the results of CFD and confirmed the validity through model tests. The analyses to assess self-propulsion performance using CFD were shown by flow line patterns on the skeg surface, nominal wake distribution in the propeller plane and the evaluation for flow balance around stern skegs. The optimized ship that was applied to the optimized two design parameters in stern skeg arrangement for target ship was derived in this work. Finally speed performance of mother ship which is existing ship and optimized ship were compared through CFD and model tests. And the usefulness about the evaluation method of self-propulsion performance was reconfirmed.

• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.1
• /
• pp.40-46
• /
• 2004

In this paper, one of the harbour manoeuvring tests is described. its goal is to investigate the so-called crabbing performance of ships. By crabbing is meant the ability of the vessel to move sideways with the use of her own manoeuvring devices like propellers, rudders, transverse thruster, etc. The crabbing model tests were carried out in the Ocean Engineering Wide Tank, University of Ulsan(UOU) to measure the transverse forces and yawing moments by the transverse thruster alone and the propeller-rudder arrangement in combination with the bow thruster. The comparison between UOU crabbing test results and data measured at one of foreign research institutes showed a little gap due to different rotating conditions of controllable pitch propellers.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.5
• /
• pp.343-352
• /
• 2016

In this study, a pre-swirl duct for the 180,000 DWT bulk carrier has been designed from a propulsion standpoint using CFD. The stern duct - designed by NMRI - was selected as the initial duct. The objective function is to minimize the value of delivered power in model scale. Design variables of the duct include duct angle, diameter, chord length, and vertical and horizontal displacements from the center. Design variables of the stators are blade number, arrangement angle, chord length, and pitch angle. A parametric design was carried out with the objective function obtained using CFD. Reynolds averaged Navier-Stokes equations have been solved; and the Reynolds stress model applied for the turbulent closure. A double body model is used for the treatment of free-surface. MRF and sliding mesh models have been applied to simulate the actuating propeller. A self-propulsion point has been obtained from the results of towing and self-propelled computations, i.e., form factor obtained from towing computation and towing forces obtained from self-propelled computations of two propeller rotating speeds. The reduction rate of the delivered power of the improved stern duct is 2.9%, whereas that of the initial stern duct is 1.3%. The pre-swirl duct with one inner stator in upper starboard and three outer stators in portside has been designed. The delivered power due to the designed pre-swirl duct is reduced by 5.8%.