| This paper is using water dynamics software AQWA to analyse and research on hydrodynamic characteristics, stability and strength of floating tidal power generation platform. In this paper, the advantages and limitations of AQWA and seven modules of AQWA (AQWA-LINE, AQWA-FER, AQWA-LIBRIUM, AQWA-DRIFT, AQWA-GS, AQWA-NAUT, AQWA-WAVE) functions were stated in detail.Firstly, analyzing the hydrodynamic characteristics of the floating platform (including F-K+Diffraction force, Steady drift force, Free folating response amplitude operator, Added mass and Radiation damping coefficient etc). The following conclusions can be obtained through the calculation and analysis:the platform’s RAOs decreases with increasing wave direction angle in three degree of freedom(DOF) of surge, heave and pitch, the RAOs along with the increase of wave direction angle increases in two degree of freedom (DOF) of sway, roll. When platform translates (surge, sway, heave) the sway RAOs is the biggest and when platform rotates(roll, pitch, yaw)the roll RAOs is the biggest, respectively are 5.3m/m and 46.6°/m. The platform translational motion, when platform heave, the added mass, the radistion damping and the F-K+diffraction force is the biggest, respectively are 80878.9kg,145350. lkg/s and 276.6kN/m. When platform rotates, the yaw D-R, the roll m-A and the pitch F-K is the biggest, respectively are 498780.6kg/s,347430.3kg and 214.7kN.m/m. When platform surge, the steady drift force decrease with the increasing wave direction angle and when platform sway the steady drift force along with the increase of wave direction angle increase. The surge and sway F-S maximum value appeared in head sea and beam sea respectively, are 39.0kN/m2 and 41.7kN/m2. The yaw F-S maximum value appeared in 15° wave direction angle, is 63.4kN.m/m2.Secondly, after analyzing the time domain and response spectrum analysis of floating platform under random wave and rules wave and irregular wave respectively. Analysis results show:Under random waves, when encountering bow sea, head sea and beam sea the platform’s yaw, surge and sway motion response amplitude is one of the biggest respectively. Through comparing the motion response amplitude of platform in the damaged condition and complete conditions (the damaged condition has a mooring line breakage but the complete conditions is no). The result indicates, when the moment of the mooring line breaks, the motion response of platform in all directions has greatly increased, in which the yaw motion response amplitude in damaged condition is 6-7 times than complete conditions. Under the regular and irregular waves, the platform translational motion, when encountering head sea, beam sea and bow sea, the heave response amplitude is the biggest and the sway response amplitude is the minimum. The platform rotational motion, when encountering head sea and bow sea the pitch response amplitude is the biggest and when encountering beam sea the roll response amplitude is the biggest. Comparing the platform’s influence in two kinds of wave after can know the random wave is more suitable for the platform design. Under the complete conditions, when encountering head sea the platform’s response spectrum is bigger than that encountering bow sea and beam sea; under the damage work condition, complete self storage condition and damage self storage condition, when encountering beam sea the platform’s response spectrum is more bigger; under extreme conditions when encountering bow sea the platform’s response spectrum is more bigger.Last, the strength of platform was analysed by using the inertia release. Results show: When the platform encountering bow sea, the wave force is the biggest. The stress component of Z direction is larger than that of X and Y. Its stress position is mainly concentrated in the range of 0-600 nodes. Combined with the specification, we can draw a conclusion that its strength satisfies the safety requirements in working conditions. |
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