김용환 교수

The present paper introduced a computer program, called WISH, which is based on a time-domain Rankine panel method. The WISH has been developed for practical use to predict the linear and nonlinear ship motion and structural loads in waves. The WISH adopts three different levels of seakeeping analysis: linear, weakly-nonlinear and weak-scatterer approaches. Later, WISH-FLEX has been developed to consider hydroelasticity effects on hull-girder structure. This program can solve the springing and w

The flow field created by a vibrating cantilever plate was studied using phase-resolved particle image velocimetry measurements as well as a smoke visualization technique. The cantilever is 38 mm wide, 31 mm long, and is actuated by a piezoelectric material. It is immersed in initially quiescent air, i.e., no free stream velocity is imposed on the system. The cantilever’s vibration frequency in these experiments is set to 180 Hz—the fundamental natural frequency of cantilever. The flow is quite

A computational study on the sloshing problem coupled with ship motion in waves is introduced. The ship motion excites the sloshing flow in the ship's liquid cargo, and the slosh-induced forces and moments affect the ship motion in return. This study applies a numerical method to solve the coupling problem of the ship motion and sloshing flow. In particular, it concentrates on the anti-rolling tank, which has the most significant coupling effects of two problems. The three-dimensional sloshing f

This paper introduces a real-time digital twin for ship operations in seaways. The concept of the digital twin is becoming popular, and it is adopted for ship operation systems in this study. In particular, this paper introduces a new and innovative concept of the digital twin to predict ocean waves and hydrodynamic performances, such as seakeeping and maneuvering, which enables the risk and optimum route to be forecast in real time. An essential element in the realization of such a real-time di

This paper proposes a numerical method for analyzing whipping using a fully coupled hydroelastic model. The numerical analysis method utilizes a 3-D Rankine panel method, 1-D/3-D finite element methods, and a 2-D generalized Wagner model, which are strongly coupled in the time domain. The computational results were compared with those of a model test of an 18 000-TEU containership. The slamming pressures and whipping responses to regular waves for bow flare and stern slamming were compared. Furt

The present paper introduced a computer program, called WISH, which is based on a time-domain Rankine panel method. The WISH has been developed for practical use to predict the linear and nonlinear ship motion and structural loads in waves. The WISH adopts three different levels of seakeeping analysis: linear, weakly-nonlinear and weak-scatterer approaches. Later, WISH-FLEX has been developed to consider hydroelasticity effects on hull-girder structure. This program can solve the springing and w

This study deals with a benchmark test on the performance of seakeeping analysis codes, which was carried out as part of the 2nd ITTC–ISSC joint workshop in 2014. Eleven institutes participated in the benchmark test with seventeen analysis codes. The target ship was the 6750-TEU containership, and the test of its flexible scale model was conducted by KRISO. A test matrix was composed of one condition for linear responses and three conditions for nonlinear responses. Participants were requested t

The effect of different bow shapes on the added resistance in waves was observed through a series of model tests. To this end, three different hull forms of KRISO Very Large Crude Carrier 2 were considered: an original hull form and two modified hulls with different bow shapes, called ax-bow and leadge-bow. The model tests were conducted for a wide range of wavelengths with two wave amplitudes in a regular head-sea condition at the design speed. Each test condition was imposed at least twice in

This study considers a comparative study on pressure sensors for the measurement of sloshing impact pressure. For the comparative study, four pressure sensors are used: one piezoresistive sensor, one piezoelectric sensor, and two integrated circuit piezoelectric (ICP) sensors. For the comparative study, the sensors are installed on tank wall and ceiling of a rectangular tank with narrow breadth. Several types of comparative studies are carried out, including the sensitivity to temperature differ

In this paper, the added resistance of a large tanker is estimated experimentally and numerically in oblique sea. Experiments on ship motion response and added resistance in oblique sea are performed in the SSPA seakeeping basin. The experiments are conducted using the self-propulsion test for seven wave directions between 180° and 0°. In the self-propulsion test, the added resistance is estimated from the difference between the thrust of the propeller in calm water and waves. In the case of the