Marine Hydromechanics
Marine Hydromechanics:
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.
Achievements:
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—liquid 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.