선박의 추진기에 의한 흐름발달과 저면변화에 대한 연구

Abstract

The flow zone through propeller jets is used in evaluating the environmental and constructional effects of navigation on the waterways. Water in this zone can go through the propellers but not all water in this zone will go through the propellers. It relies on the characteristics of ships and water depth. A numerical model using the momentum theory of the propeller and Shield's diagram was developed in a restricted waterway. Equations for discharge are presented based on thrust coefficients and propeller speed and are the most accurate means of defining discharge. Approximate methods for discharge are developed based on applied ship's power. Equations for discharge are as a function of applied power, propeller diameter, and ship speed. Water depth of the waterway and draft of the ship are also necessary for the calculation of the grain size of the initial motion. The velocity distribution of discharge from the propeller was simulated by the Gaussian normal distribution function. The shear velocity and shear stress were from the Sternberg's formula. Case studies to show the influence of significant factors on sediment movement induced by the ship's propeller at the channel bottom are presented. The first case is for large ships passing through the navigation channel and berthing and unberthing at container terminal at Kwang Yang harbor.

Eleven ships are considered, including naval ship, tanker and bulk carriers.

The second case is for the commercial moving tow and the barge. The combined effects of the propeller jet and the wake flow a moving barge are investigated.