• 대한조선학회논문집
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• 제34권4호
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• pp.72-83
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• 1997

본 연구에서는 연안 및 운하, 두 곳 모두에서 운항이 가능한 컨테이너선에 대한 선형설계를 수행하였다. 설계된 선형은 기존의 140TEU 컨테이너선을 기준선으로 하여 설계된 200TEU급 컨테이너 선형으로, 선수부에 대하여는 기존의 저항시험 자료들을 통한 선형의 재설계도 시도되었다. 모형시험은 선형시험수조에서 일반적인 저항시험을 통한 전저항, 침하와 트림(trim)이 제측되었으며, 선체주위 유동장의 해석을 위한 수치해석으로는 무한수심 뿐만 아니라 제한수로상태에 대하여도 MAC법을 기초로 한 유한차분법(Finite-Difference Method)에 의해 계산이 수행되었다. 이러한 일련의 모형시험 및 유동장의 수치해석을 통하여 설계된 선형의 저항 특성을 파악하였다.

• 수산해양기술연구
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• 제37권4호
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• pp.308-312
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• 2001

이상에서와 같이 LCG위치에 따른 일련의 실험으로부터 다음과 같은 결론을 도출하였다. 1. 선형개발에 있어서 최적선형을 선정하고 이에 대한 성능검증의 일부로써 최적의 LCG위치를 찾는 것은 일반배치의 고려 및 실선에서의 운항 경제성 결정에 중요한 역할을 하며, 이와 같은 연구자료를 데이터 베이스화 함으로써 앞으로의 선형개발에 있어서 유용하게 쓰이게 될 것이다. 2. 저항시험 결과로부터 선미방향으로 LCG위치를 2% 포인트씩 이동하게 되면 서서히 저항이 감소하다가 8%포인트 위치에서 최저점을 이루며 이는 실선속도 25노트에서 초기상태(0%LCG)에 비해 만재상태에서는 약 12.4%, 시운전 상태에서는 약 10%의 저항감소효과가 있었다. 그 이후 (10%LCG)부터는 다시 저항이 증가하게 되는데, 이는 선수트림이 커지게 되면서 선저의 활주면에 과도한 동적 압력이 발생하게 되고, 저항감소의 원인이 되었던 침수표면적의 감소로 인한 마찰저항의 감소보다 동적압력에 의한 압력증가 영향이 더 커지게 된 것으로 추측된다. 3. 나선상태에서보다 스프레이스트립(spray strip) 및 스케그 등과 같은 선형에 적합한 부가물을 부착하면 저항감소 및 직진성능 (course keeping ability) 향상 등의 이점이 있다. (이 논문의 결론 부분임)

• Journal of Biosystems Engineering
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• 제13권2호
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• pp.28-37
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• 1988

This study was conducted to construct the soil bin system and associated microcomputer-based data acquisition system which is to be used for the effective evaluation of wheel performance. The soil bin system consists of four main parts; soil bin, carriage drive system, test carriage and soil processing carriage. The test carriage was constructed to measure the five performance parameters of testing wheels; pulling forte, motion resistance, sinkage and rotational speed of test wheel, and speed of test carriage. The test wheel is powered by a hydraulic system up to 8 ps. Soil processing carriage was designed to provide uniform test soil condition across the toil bin, and reproduction of soil conditions found satisfiable. The data acquisition system consists of APPLE II PLUS microcomputer, strain amplifier, I/O interface, A/D converter, digital counter and various transducers. It takes about 0.86 seconds to measure a set of performance parameters and store on the floppy disk simultaneously. Series of experiment showed that this system can be used effectively for evaluating the wheel performance associated with soil.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권1호
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• pp.20-26
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• 2011

A weakly nonlinear seakeeping methodology for predicting motions and loads is presented in this paper. This methodology assumes linear radiation and diffraction forces, calculated in the frequency domain, and fully nonlinear Froude-Krylov and hydrostatic forces, evaluated in the time domain. The particular approach employed here allows to overcome numerical problems connected to the determination of the impulse response functions. The procedure is divided into three consecutive steps: evaluation of dynamic sinkage and trim in calm water that can significantly influence the final results, a linear seakeeping analysis in the frequency domain and a weakly nonlinear simulation. The first two steps are performed employing a three-dimensional Rankine panel method. Nonlinear Froude-Krylov and hydrostatic forces are computed in the time domain by pressure integration on the actual wetted surface at each time step. Although nonlinear forces are evaluated into the time domain, the equations of motion are solved in the frequency domain iteratively passing from the frequency to the time domain until convergence. The containership S175 is employed as a test case for evaluating the capability of this methodology to correctly predict the nonlinear behavior related to wave induced motions and loads in head seas; numerical results are compared with experimental data provided in literature.

• 대한조선학회논문집
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• 제46권3호
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• pp.268-278
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• 2009

The present study focused on evaluation for the performance of the Flow Control Flat Plate (FCFP) attached in the stern side of the ship. The important function of this FCFP is to enhance the resistance performance through the decrease of stern sinkage and the propulsive performance by the adjustment of inflow velocities in the propeller plane. Two different hull forms were considered to identify the effects of the FCFP. The attachment position, the angle and the size of the FCFP were studied in this numerical simulation. In this paper, the roles of the FCFP were intended to analyze fully through the numerical interpretation.

• 대한조선학회논문집
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• 제46권3호
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• pp.335-342
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• 2009

Motion characteristics of a planing craft are sensitively changed according to its weight and longitudinal center of gravity. In this paper, planing craft model tests were performed in calm water for various test conditions and Froude numbers. Sinkage and trim were measured to analyze the relations between the attitudes of a planing craft and the weight and center of gravity of it. Theoretical formula for the prediction of the attitudes of a prismatic planing hull was modified so that it can be applied to the prediction of the attitudes of a non-prismatic planing hull, and the calculation results by the modified formula were in good agreements with the experimental data.

• 한국CDE학회논문집
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• 제19권4호
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• pp.332-339
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• 2014

This paper presents on the development of wheel-terrain interaction device using low-priced sensors, which will be used to predict the drawbar pull and optimal slip of off-road vehicle in real time. The essential variables obtained in the device to predict the mobility of vehicles are determined based on semi-empirical model describing the wheel-terrain interaction. Using the developed device, the experiments about the wheel-terrain interaction were performed on the soil of the Jumunjin standard sand, which yielded dynamic weight, motor driving torque, drawbar pull, and sinkage with respect to wheel slip ratio. Finally, the repeatability of the measured data are verified through repeating the experiments three times on the same condition.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.277-282
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• 2004

This paper concerns about dynamic analysis of an underwater test miner, which operates on cohesive soil. The test miner consists of tracked vehicle and pick-up. device. The motion oj pick-up device relative to the vehicle chassis is controlled by two pairs of hydraulic cylinders. The test miner is modeled by means of a commercial software. A terramechanics model of cohesive soft soil is implemented to the software and applied to dynamic analysis of the test miner model. The dynamic responses of test miner are studied with respect to of four different types of terrain conditions.

• 한국해양공학회지
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• 제29권6호
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• pp.405-410
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• 2015

This paper reports the hull form development and resistance performance of a 5-ton-class catamaran-type coastal fishing boat. The weight estimation and preliminary design were basically extracted from existing coastal fishing vessels. In addition, the resistance performance was investigated using a model test in a high-speed circulating water channel and was analyzed in comparison to an existing catamaran fishing vessel. As a result, the modified hull achieved an approximately 30% reduction in resistance compared to the previous hull. The stability or boarding sensitivity of the modified hull form was more stable or comfortable than the original hull form based on a trim and sinkage comparison between the two boats.

• Journal of Hydrospace Technology
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• 제2권2호
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• pp.68-79
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• 1996

The present report describes the results of the cooperative experimental study organized by the High-Speed Marine Vehicle Committee of the Korea Towing Tank Conference. The study aims to improve model test technique and accuracy and to self-evaluate their own capabilities. The resistance tests of a 23m class planing hull were performed at the towing tanks of the Korea Research Institute of Ships and Ocean Engineering (KRISO), Hyundai Maritime Research Institute (HMRI), Seoul National University (SNU), Inha University (IU) and Pusan National University (PNU). In addition, the longitudinal wave cut was measured antral and analyzed at the KRISO. All the results of total resistance, trim and mean sinkage are presented in this report and the results show fairly good agreements comparing with the ITTC HSMV committee's report.