• The Journal of the Acoustical Society of Korea
• /
• v.40 no.4
• /
• pp.314-319
• /
• 2021

The measurement of the Underwater Radiated Noise (URN) for the underwater vehicle should consider both the acoustic interference due to the surface reflection and the calculation of the Closet Point of Approach (CPA). In this paper, I tried to analyze the underwater vehicle's URN using the Lloyd's mirror effect. First, the theoretical Lloyd's mirror pattern was compared with the sea trial result, and the sea trial results corresponded well with the theoretical predicted pattern. And then the CPA distance could be estimated by the Lloyd's mirror pattern. As a results, acoustic source level shows the spectral fluctuation due to the acoustic interference of the Lloyd's mirror effect.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.131-136
• /
• 2017

High speed under water vehicle by using solid rocket motor, which is a natural cavitation type, was tested. The vehicle's speed and running distance was measured, and pressure sensors installed on the surface of the vehicle show pressure-time history of pressures according to the development of the supercavitation. Underwater cameras installed on the wall of the test pool recorded whole processes from the onset of the supercavitation to fully developed one. CNU-SuperCT based on 2-dimensional inviscid theoretical analysis was used to simulate the test result. In consideration of CNU-SuperCT does not include the control fins of the vehicle, simulation results agree with test results very well. Also, pictures from underwater cameras support the test results.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.4
• /
• pp.12-17
• /
• 2018

A natural cavitation-type high-speed underwater vehicle with solid rocket motor is tested, and its speed and running distance are measured. The outputs from pressure sensors on the surface of the vehicle reveal a pressure-time history reflecting the development of supercavitation. Underwater cameras installed on the wall of the test pool record the entire process from the onset of supercavitation to its full development. CNU-SuperCT, based on two-dimensional inviscid theoretical analysis, is used to simulate test results. Considering CNU-SuperCT does not include the control fins of the vehicle, simulation results agree with test results very well. Additionally, pictures from underwater cameras support the test results.

• Journal of Navigation and Port Research
• /
• v.29 no.8 s.104
• /
• pp.679-684
• /
• 2005

In this paper, 6-DOF motion equations of UUV (Unmanned Undersea Vehicles) are derived Moreover, the hydrodynamic maneuvering derivatives are found from the oblique towing test of the 2m Manta type UUV model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.63-68
• /
• 2005

In this paper, 6-DOF motion equations of UUV (Unmanned Undersea Vehicles) are derived Moreover, the hydrodynamic maneuvering derivatives are found from the oblique towing tests of the 2m Manta type UUV model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2016.05a
• /
• pp.110-112
• /
• 2016

In this paper, the captive model test of submerged body using RA test was carried out at the Square Basin. The target model is a submarine with four different types. For the comparison between theory and measurement, hydrodynamic coefficients are calculated according to the described method and compared with RA measurements on Submarine models. in addition, horizontal stability index of underwater vehicle was checked.

• Journal of the Society of Naval Architects of Korea
• /
• v.32 no.2
• /
• pp.1-9
• /
• 1995

This paper suggests a numerical method that creates and varies hull form geometry of underwater vehicle. That is, it induces the cylindrical underwater vehicle from principal dimensions-total length, the length of parallel middle body, the coefficient defining entrance & run parts etc.-and represents using NURBS curve. Also, each section of hull form is varied by user interface and Sectional Area Curve is generated.

• Journal of the Korea Society for Simulation
• /
• v.31 no.4
• /
• pp.11-22
• /
• 2022

Unlike a short-range, a long-range underwater acoustic communication(UWAC) uses low frequency signal and deep sound channel to minimize propagation loss. In this case, even though communication signals are modulated using a covert transmission technique such as spread spectrum, it is hard to conceal the existence of the signals. The unconcealed communication signal can be utilized as active sonar signal by enemy and presence of underwater vehicles may be exposed to the interceptor. Since it is very important to maintain stealthiness for underwater vehicles, the detection probability of friendly underwater vehicles should be considered when interceptor utilizes our long-range UWAC signal. In this paper, we modeled a long-range UWAC environment for analyzing the detection performance of underwater vehicles and proposed the region of interest(ROI) setup method and the measurement of detection performance. By computer simulations, we yielded parameters, analyzed the detection probability and the detection performance in ROI. The analysis results showed that the proposed detection performance analysis method for underwater vehicles could play an important role in the operation of long-range UWAC equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.83-85
• /
• 2015

The Purpose of this paper was to carry out basic study on development of real-time submarine-hnadling simulator. The author adopt the Unmanned Undersea vehicle(UUV), which has taken the shape of manta[1]. They call here it Unmanned Undersea Vehicle(UUV). UUV is based on the same design concept as UUV called Manta Test Vehicle, which was originally built by the Naval Undersea Warfare Center, USA[1]. The present study deals with prediction of manoeuvring motion of UUV at general drift angles and large drift angles. The dynamic mathematical model with six degrees of freedom is revised and supplemented in order to describe accurately motion of UUV. The hydrodynamic derivatives related to motion are obtained from previous work[2].

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.11a
• /
• pp.8-9
• /
• 2011

본 논문에서는 수상 및 수중운동체의 안정성 및 안정화기법에 관해 고찰한다. 선박이 운동을 하게 되면 부가질량이 변하게 되고 대칭인 시스템행렬이 비대칭이 된다. 비대칭성에 따라 시스템의 안정성해석방법도 달라지는데 예를 들어 가속도 피드백을 통해 비대칭요소를 제거하여 대칭으로 변환시키는 것이 가장 대표적인 해석 및 안정화 기법이다. 시스템 모델자체는 어디까지나 모델이기 때문에 대상시스템을 명확하게 수식으로 표현할 수 없으므로 피드백에 의한 비대칭요소를 소거시키는 방법은 타당하지 못하다. 따라서 본 논문에서는 대칭행렬이 비대칭행렬로 변하는 제약에 구애받지 않는, 보다 일반성을 갖는 안정성해석법을 제안한다.