Showing 4 results for Hydrodynamic Analysis
Mr Hamid Sarlak, Mr Mohammad Saeed Seif, Mr Majid Abbaspour,
Volume 6, Issue 11 (9-2010)
Abstract
The important characteristic of sea waves is their high energy density, which is the highest among renewable energy sources. Having up to 2700 km. of shoreline, Iran has a great potential in construction of offshore wave buoys (hereafter called OWB). In this article a OWB model with the possibility of assembling different buoy configurations is introduced. The system is exposed to regular and irregular waves which are generated using wave maker in a 2D wave tank. Wave energy can be extracted from vertical oscillation of its floating buoy. The device is so designed as to operate in rotational (pitch) mode in addition to vertical (heave) motion.
Some experiments are also conducted to demonstrate system performance. Experimental results in different conditions are presented and the effect of different buoy configurations on the system efficiency is studied. Numerical simulations that obtain the hydrodynamic coefficients and dynamic response (the Response Amplitude Operator or simply RAO) of each buoy in waves validate test results that the buoy with highest transfer function obtained in simulations has highest efficiency in power extraction. It is finally shown that the horizontal buoy is the most efficient configuration among other constructed buoys for extracting wave energy. The non-dimensional groups are studied and the output power of a full scale OWB is obtained based on similarity laws.
Parastoo Zamani Mofrad, Saeid Kazemi,
Volume 15, Issue 29 (4-2019)
Abstract
Single Point Mooring (SPM) are floating Structures that are deployed in deep water which their duties are vessel mooring and transferring oil and gas productions by pipelines from shore to petroleum tankers and conversely. One of the most important components of SPM is mooring system. Which bears not only environmental loads but also petroleum tanker loads which conducted by two thick ropes. Mooring system of SPM regarding the important responsibility it has, has been pay attention to a lot. Proper mooring system leads to efficiency improvement in different environmental conditions and mooring system life increase.
In this research SPM with four mooring lines are simulated by ANSYS AQWA Software and forces on the SPM calculated diffraction theorem and Boundary Element and mooring lines are calculated by Morrison theorem.
Marzieh Sayyadi, Mohammad Reza Zareei,
Volume 17, Issue 34 (12-2021)
Abstract
The mooring design of floating structures is one of the important parts in the design process of offshore structures. To design and evaluate the performance of mooring lines, criteria such as ultimate strength and fatigue have been defined. In real conditions, mooring forces are random variables, so to check the strength, the statistical distribution of mooring forces under the influence of environmental condition must be calculated at first. In this article, a statistical study of the mooring force of a semi-submersible offshore wind turbine, which is stabled by three catenary-chain mooring lines, has been considered. Hydrodynamic analysis of the structure was performed by ANSYS-AQWA software and the environmental characteristics of the area were extracted from the DNVGL standard for the Mediterranean Sea. During the life of the structure, due to corrosion, the diameter of the mooring chain decreases. Therefore, in this research, the condition of the mooring lines from the perspective of tensile forces has been investigated by considering the corrosion at a constant annual rate. During the life of the structure, due to corrosion and as a result the reduction of the axial stiffness, the tension of the mooring lines will be reduced. This amount of reduction for the critical mooring line in 10-year intervals of its 30-year lifetime is 5.4, 13.1 and 21.3 percent, respectively.
Mohammad Javad Eslahi, Saeid Kazemi, Mojtaba Ezam, Madjid Ghodsi Hassanabad,
Volume 19, Issue 41 (12-2023)
Abstract
A study was conducted on the initial stages of floating wind turbines design, which face significant challenges. The research focused on the comprehensive investigation of the aerodynamics of wind turbines, hydrodynamics of floating platforms, and dynamics of mooring lines. The study also examined the interaction between these components and their effects on each other. The research introduced a new design for the heave plate, optimizing its dimensions for supporting a 5-MW wind turbine in deep offshore waters near Jask Port in the Oman Sea. Through numerical simulations, the study evaluated the coupled dynamic responses of the floating wind turbine system to wave loads, currents, tides, and winds. The findings demonstrated that the optimized heave plate effectively met operational requirements under normal and severe conditions. Additionally, the study highlighted the superior performance of the optimized heave plate in the structural-wave interaction, providing satisfactory results.
