The Relevance Study Between The Parameter Changes Of Pressurized Area And Vortex-induced Vibration Of Marine Riser

There has quite a number of valuable research results among the mechanism of VIV,but among these results,there are few studies covers the relevance between fluid state of pressurized area and VIV.Firstly,from the theory of boundary layer,this article divides the fluid domain into three area:wake area & boundary layer & external potential area,and makes a detailed analysis of the shape variation of fluid for VIV.Then establish a numerical analysis program and verify its reliability with the use of ICEM and CFX.Secondly,this article makes the research of VIV by single cylinder within the scope of low Reynolds number,which focuses on the changes of fluid form in pressurized zone.The results showes that,with the increase of Reynolds number,the gradient of the fluid pressure in the pressurized area is increasing,and the scope of the pressure oscillation is also continuing to increase by a linear trend.Thirdly,this article makes the research under the condition that the wake region with or without fairing device to anslyse the effect of the changes of fluid in pressurized area to VIV.The results showes that,whether there is a direct interference in wake zone,when the same kind of interference pattern is applied in pressurized area,if the distribution of its pressure and vibration amplitude along the surface of riser becomes more gentle,the weaker of the intensity of VIV.This relevance may be separately described by comprehensive factor ￡ and comprehensive suppression effect Ω,that is,the greater the ￡,the smaller the Ω.Lastly,on the basis of summary of the structure characteristics of typical suppression devices,and associate with the analysis conclusions of the relevance between the ￡ and the Ω,a new suppression device named “the subsidiary tubes with helical panel”was proposed by this paper.Through simulation experiments,we found that the new suppression device have good suppression effect for the fluid flows in different directions,and the relevance between its suppression effect and fluid parameters of pressurized area is the same as the relevance between the ￡ and the Ω.