고속활주선의 워터젯 유입면 형상이 저항성능과 조종성능에 미치는 영향

Abstract

Waterjet propulsion system is popularly adopted for a high speed planning boat for its high propulsion efficiency at high speed. For a ship with a waterjet, waterjet intake shape is known to influence the waterjet performance greatly. In case of a planning boat, the waterjet intake shape influences also the resistance and manoeuvring performance greatly by changing stern pressure field and running attitude of the boat. In this study, the effect of waterjet intake shape on the resistance and manoeuvring performance is investigated for a high speed planning boat through model test and CFD analysis. Model resistance test was performed at high speed towing tank and manoeuvring test was done by free running test inthe lake. CFD analysis was carried out using SNUFoam which has been developed based on OpenFOAM. SNUFoam applies VOF(Volume Of Fluid) method to capture free surface. Since VOF method has some problem to get accurate free surface, such as interface smearing problem, SNUFoam adopts dynamic interface compression method to solve free surface accurately, which is very important for the computation of high speed planning boat. Test ship is a 3-ton class planning boat with a maximum speed of 45knots which has been developed for a USV(Unmanned Surface Vehicle) by KRISO. Three different waterjet intake shape was investigated to see their effects on the resistance and manoeuvring performance of the test ship.