| With the acquisition and development of deep-sea oil and gas,traditional offshore platforms are no longer adapted to the requirements of deep-sea oil production because of cost and self-weight.Many floating platforms have gradually replaced them,such as semisubmersible platforms.Due to the complex environment of the deep sea,the safety of the platform is deeply jeopardized.Wave creates run-up around the platform pillars,creating a strong slamming effect on the columns and even the deck.Therefore,it is very important to study the wave run-up law,slamming effect,near-field interference and factors affecting wave run-up of semi-submersible platforms.In this paper,the CFD software FINE/Marine based on viscous flow theory is used to carry out numerical prediction of wave run-up,near-field interference and column slamming on semi-submersible platforms in two modes(fixed mode and mooring mode),combined with self-programming software Matlab processes and analyzes the numerical results.The specific research work and conclusions are as follows:Analyze the wave run-up change of the front column and the front column and the influence of the platform mode on the wave run-up;discuss the influence of the wave steep parameter KA and the scattering parameter KR on the wave run-up of the platform column;study the nonlinearity of the wave around the column affect the wave run-up of the column.The results show that the wave climbs up with the decrease of the distance from the column;the wave run-up in the week is “W”;the larger KA and KR have a certain influence on the wave run-up;the wave is nonlinear around the column.Features are constantly increasing.The influence of the six-degree-of-freedom motion of the platform on the slamming of the column is analyzed.The general law of the slamming pressure of the column in different modes is discussed.The near-field interference of the platform in the different modes is studied.The wave front distribution characteristics inside the platform during interference.The results show that the column slamming has periodicity and is consistent with the wave period;the mooring mode exacerbates the column slamming effect and the internal wave front fluctuation.Aiming at the influence of main factors of semi-submersible platform on wave climbing of columns,the wave climbing changes of front and rear columns of semi-submersible platform with different column shapes(square,chamfered,circular)and the distance between front and rear columns(2.0D,2.4D,2.8D)in fixed mode are compared and analyzed,and the opposition between column shape and distance is discussed.The influence of wave climbing around the column and the influence of different column shapes and spacing on the wave surface distribution in the inner field are investigated.The results show that the shape of the column mainly affects the wave-front surface of the column and the wave-climbing in one week,and the spacing between the columns seriously affects the wave distribution between the two columns.The shape and spacing of the column have a great influence on the peak value of the wave surface and the variation of the wave surface in the internal field. |
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