Research On Theoretical Calculation And Simulation For The Maneuerability Index Of Inland Navigation Ships

In recent years, with the flourish of the world's seafaring, our country's seafaring is rising rapidly. Our country inland waterways navigation mileage is up to 1.33 million kilometers, accounting for about 32 percent of the overall length of rivers. There are more than 1,300 inland ports in the nationwide, in which about more than 200 are berths of DWT, and their water comprehensive transportation capacity is the first all over the world. After years of construction and development, the Yangtze river route has become the busiest and largest traffic volume of rivers in the world's waterway transportation. Especially after the Three Gorges Project completed and started to retain water, the water level of the inland channel in Yangtze River 's upstream rises, then the 10000 ton class fleets can sail through smoothly, furthermore water transportation is more convenient from inland to coast. But most inland channels in our countries are circuitous and changeable, meanwhile the current condition are complicated, consequently, once the ships confronted with collision or touch-and go, even worse, when crude oil or chemicals leak , environmental pollution and ecological damage will follow, in addition, the life of people who live along the river suffer most directly. So that the inland waterways ship navigation safety is of much importance.Research on the conditions of inland channel ship navigation by using small scale self-propelled ship model is a new technology which has been used in shipping-developed countries. It can reflect navigation conditions of channel more actually and directly and is an effective means to improve the quality of inland navigation conditions research. It also has played an important role on research of inland navigation conditions, such as Three Gorges etc. Using small scale self-propelled ship model to study problem of navigation must meet certain navigation conditions,besides geometric similarity, dynamic similarity, and displacement similarity, there is an important link to meet maneuerability similarity with model ship and real ship. Due to the influence of scale effect and so on, the deviation exist between small scale self-propelled ship model and real ship. So it is necessary to obtain the maneuerability index of real ship,such as K and T etc, which serve as the foundation of ship model maneuerability 's calibration and correction. The usual practice is to use real ship test to obtaini maneuerability index K and T of real ship .However, due to the confine of objective conditions, it is often unable to get K and T index through the real ship test.Therefore, the K and T index of the real ship maneuverability that we get from the method of simulation which serve as the foundation of ship model maneuerability's calibration and correction seems particularly meaningful.In order to acquire actual maneuerability index,according to present frontier research on ship's maneuverability and derivation of equation on hydrodynamic force derivative of ship's maneuverability, combined with some empirical equation, authors list equation of motion on ship's maneuverability at the base of the ships' stressing condition,furthermore, they use highly intensive cubiccorrected rungekutta'smethod to compile computer program and carry on analogically simulated computation with reference to actual ship parameter .In addition, complemented with research trial on self-propulsion small-scale ship model ,they analyze the restriction of rudder areal to ship's maneuverability and find out the connection of rudder with ship's maneuverability, in that way, the rudders can match best with ships as a reference to enhance the operating characteristic of the ships.In this paper,ship's maneuverability mobility (10°) Z-shaped graph obtained from analogically simulated computation through Microsoft Visual Basic program is generally the same to the (10°) Z-shaped graph derived from the full scale test, and there is some deviation between K′index and T′index, the maximum of the K′index's deviation is -2.52%,,while the minimum is -1.34%,,the maximum of the T′index is -8.22%,while the minimum is +2.76%, still, relatively ideal effect is acquired and can be the reference of ship model calibration.In the analyze of the relation between rudder area and ship's maneuverability, a conclusion that ship's maneuverability doesn't get better as the rudder area grow larger is summarized. there is a critical value between rudder area and ships, so the best configuration between rudder and ships should be confirmed according to the influence from the shapes and draught of the ships.