The Method For The Estimation Of Motions Of Box-shaped Ship In Waves

The project ship took the special ship an important branch, in the national economy modernization is essential ship style. Along with our country harbor, the route scour, the water conservation renovates as well as the ocean development enterprise vigorous development, the project ship function can more and more remarkable, it will include the variety and the type application will be also more widespread.Regarding some tow-boats and the ferryboats in inland rivers, in the sea each kind of work platform ship and the project ship as well as the boat bridge all may regard as the box-shaped ship, the box-shaped ship is one of project ship fundamental modes. Quite of length and breadth is small, even approaches 1. Quite is serious as a result of this kind of ship style fluid motion three dimensional influence, therefore the traditional strip theory is difficulty to give the precise result. Therefore this article uses approach of longitudinal and transverse strip dividing to calculate the ship motion of length and breadth ratio to1 in wave, proposed one project estimate method. So-called longitudinal and transverse strip dividing, is when calculates the hydrodynamic coefficient or the wave force of the ship, either uses traditional the transverse strip dividing, either uses with it vertical longitudinal strip dividing, or uses two some kind of mean value.First calculates the hydrodynamic coefficient of the single section plane in the frequency range, including added mass and damping coefficient. Using the approach of longitudinal and transverse strip dividing we can obtains the hydrodynamic coefficient of the ship. Then the computation single section plane wave force, according to this approach, calculates the entire ship the wave force. Establishes the movement equation of the ship, and then considerate the revision of the damping. Compare result of the calculation with experimental value will confirm this method the feasibility. And the change length and breadth, the discussion different length and breadth compares under the condition the box shape ship in wave state of motion. The motions in sea can be treaded as stationary random process .This paper use spectral analysis to predict the statistical values of motions accelerationThe present paper's theoretical calculation is based on longitudinal and transverse strip dividing, it is one project estimate method, two-dimensional section plane hydrodynamic coefficient collects the distribution method solution by the source. Although theoretically is not really strict, but may obtain with the experiment down to the three dimensional theoretical calculation quite result. Therefore the paper research work has the project application significance.