As a consistent source of ship type development and innovation, this research direction is of vital importance to researches concerning the new fore-and-aft resistance reducing and efficiency increasing technology of main ship types such as bulk carriers, oil tankers, container ships, theory and design of high efficient and energy-saving propeller, ship energy-saving devices, ship-machine-paddle match characteristics, etc. All these researches are inseparable from the study and innovation of basic theory of ship hydrodynamic performance and control technology. Ultimately this research direction is a basic research aiming to interpret the complex flow phenomena and to predict and control ship strong nonlinear/ dynamic loads and response. It mainly consists of modeling, fine measurements and CFD research techniques.
1. Prediction of Ship Resistance and Optimization of Hull Form
Through model testing, we verify the validity of theoretical methods, such as forecast performance, optimization of hull form and optimization of layout. As a result, we obtain a better and optimized hull form. The successful completion of a number of ministerial level research projects helped many research, development and optimization of design work for some important domestic ship design institutes with good effects.
--Prediction theory and software on resistance and effective horsepower suitable for mono-hull, catamaran and trimaran.
--Optimization methods for mono-hull, catamaran and trimaran.
--Optimization methods of hydrodynamic layout for trimaran.
Comparison between effective horsepower calculation and test result
2. Two-half dimension theory for predicting high-speed ship motion
Based on the slender demihull characteristics of high-speed hull and multihull, we propose two-half dimension definite solutions problem adopting two-dimensional Laplace equation and three-dimensional free surface conditions with speed. Though time and space conversion, the definite solutions problem is transformed into a object plan nonlinear problem in the two-dimensional time domain. A complete object plan boundary integral equation based on two-dimensional transient free surface Green¡¯s function is also given. Compared with international solution using discrete free surface and simple Green¡¯s function of object plane, the new theory greatly improves the accuracy and efficiency of the flow field solution and gives the algorithm of hydrodynamic stability. Certain programs based on the innovation and development of the new theory has been applied to high-speed monohull, catamaran, wave-piercing catamaran, and trimaran motion and wave loads prediction. Our theory successfully guides the design of high-performance vessel.
3. Deepwater floating structures coupling and external load analysis
Our research targets are as follows: to improve the computing method about deepwater floating structures concerning nonlinear coupled motion and external load analysis; to develop a set of international level calculation software for deepwater floating structures coupled motion and load analysis with own intellectual property rights; to establish a related guiding principles, providing basic technical support for the development of deep sea engineering equipment. HEU has a oceaneering basic research and software development with the largest national investment.
4. Key Technology of the Sharp Sloshing Test of Liquid Tank¡ªliquid tank sloshing under horizontal SHM
Liquid tank sloshing is a sloshing phenomenon of liquid in the liquid tank because of severe sea conditions. Impact pressure caused by sharp sloshing will cause damage to tank bulkhead and other motion performance, even causing instability and overturning accident under severe conditions. The test mainly studies the top impact and rolled wave front phenomenon of the rectangle liquid tank with clapboard under the horizontal SHM (Simple Harmonic Motion). We measured the impact pressure of top corner and clapboard, recorded stress waveform and studied the change of impact pressure with a variety of filling ratio. Our research also studied the impact of clapboard location on impact pressure. This experiment was carried out in the Laboratory of Mechanical Structure of HEU. A test liquid tank was made, corner and clapboard were arranged and ten pressure sensors were installed. The test was completed with a successful result.
Future Research Directions:
(1) The R & D of digital pools technique;
(2) Research on analysis and prediction technology of trimaran hydrodynamic characteristics;
(3) Research on the key technology of internal wave pool;
(4) Research on new prediction and motor control technology of nonlinear loads under high sea conditions.