Three-dimensional Numerical Simulation Of The Wave Characteristics Within A Chamber Of Ship Lift During In The Docking

In order to reduce the power of the marine electromechanical system and the project cost, in the process of ship lift's design, on the premise of meeting the design ship dimensions and freight volume, it always puts the ship reception chamber size and compartments inside to minimize the depth of the water, Its direct consequences are resulting the ship reception chamber very narrow, and the depth of the chamber is shallow. When the ship enters or leaves the ship reception chamber, only one side gate is opened, the narrow water area in the ship reception chamber is semi-enclosed. The velocity of water around the ship is accelerated when the ship is traveling in the reception chamber, so the pressure is reduced, the water level of prow side is rising, and the stern side water level is declining, the waterhead between ship's front and back is formed, then the ship is tipped and sank following with the fluctuations of water. On the one hand, the ship is prone to bottoming due to sinking, which is extremely unfavorable to the deck; On the other hand, when the ship entering and leaving the ship reception chamber, it will cause the fluctuations of water, this then will lead to the ship lift's emphasis and longitudinal tilt torque, and the water surface fluctuations must under a certain limit, once exceeded the limit may lead to ship lift's imbalance and cause accident. Therefore, the research of hydraulic characteristics of ship entering and leaving the ship reception chamber has great practical significance.This paper relies on a typical shiplift project in China, and uses the large commercial CFD software Flow-3d, Three-dimensional numerical simulation study was carried out to analyze the water fluctuation characteristics and the maximum sinking amount of the ship under different ship speed, water depth, ship type, and the following are the results:(1) The maximum sinking volume of the ship is mainly related to the speed, the ship's tonnage and the water depth. When the ship's tonnage and the water depth are the same, the maximum sinking amount increases with the increase of the speed of the ship.When the ship's speed and the water depth are the same, the maximum sinking amount of the ship increases with the increase of the tonnage When the ship's tonnage and speed are constant, the maximum sinking amount of the ship decreases with the increase of the ship's water depth..(2) By analyzing the wave characteristics of the water in the vehicle, it is found that the influence of the speed of the ship, the tonnage of the ship and the depth of water on the fluctuation amplitude of the water surface is similar to that of the ship's maximum sinking amount. But in comparison, the speed of the ship has the most obvious impact on surface fluctuations and the maximum sinking amount of ship.(3) The coupling relationship between ?, v, H and n is obtained by dimensionless processing of the ship's maximum sinking amount ?, velocity v, water depth H and ship section coefficient n, Calculation formula of maximum sinking amount of 3500t ship:?/H=1.493×V2/2gH×[(n/n-1)2-1]+0.035 , Calculation formula of maximum sinking amount of 3000t ship: ?/H = 1.457×V2/2gH×[(n/n-1)2-1+0.029 , According to the formula, the maximum amount of ship sinking 8 is predicted for different ship-lift projects, and a reasonable ship safety speed is given to guide the engineering design.