Two near field methods, namely the integral method and differential method, were presented for giving second order mean drift forces and moments between two fixed submerged bodies in regular waves. For the integral ...Two near field methods, namely the integral method and differential method, were presented for giving second order mean drift forces and moments between two fixed submerged bodies in regular waves. For the integral method, with a series of mathematical manipulations, second order drift forces and moments could be easily expressed by distributed sources which could be calculated by source distribution techniques with the assumption that the amplitude of ship motions are small on the basis of the linear 3D frequency theory. For the differential method, drift forces and moments could be expressed by the derivative of velocity potential with respect to space coordinate. Because two bodies would behave as a single body while the clearance is very large, the numerical results of one sphere in such case were given and compared with analytical results of a single sphere which does not involve the effect of free surface. When submerged depth becomes enough large, a good agreement can be reached. Then the integral method was used to predict the second order drift forces and moments of two submerged spheres and spheroids with a small lateral separation distance in waves compared with the numerical results obtained by the differential method and they agree well. By comparison, it indicates the interaction effects between two submerged bodies have a profound influence on the drift forces and moments. In this paper, the forward speed effect on submerged spheres was also considered.展开更多
The problem of petroleum safety is closely related to national politics andeconomics security and becomes one of key for discussion in China. The floating oil storage systemhas been proposed as a new facility for Stra...The problem of petroleum safety is closely related to national politics andeconomics security and becomes one of key for discussion in China. The floating oil storage systemhas been proposed as a new facility for Strategic Petroleum Reserve (SPR) in our country. There aresome differences in solving this problem. Although many of domestic research institutions arestudying the project of SPR, the research is separate, and lack of comprehensive consideration, andfails to make a complete and scientific demonstration in many aspects, such as oil storage capacity,selection of storage sites, storage facilities, technologic and economic feasibility, riskassessment, etc. Therefore, no mature and systematic petroleum reserve theories have been formed upto now. Peoples argue the issue of objective of SPR, function, mode, cost, effect, etc. There arestill many bifurcations, so, it is necessary to make more detailed demonstration, and provide somescientific decision-making strategy for the governments. In this paper, several significant problemsare solved, for instance, the option of SPR facilities, the research on the principalcharacteristics of floating oil storage vessels, the a-nalysis of mooring system for oil storagevessels, the design of breakwater and the calculation of failure probability, the risk assessment offloating oil storage system, etc.展开更多
文摘Two near field methods, namely the integral method and differential method, were presented for giving second order mean drift forces and moments between two fixed submerged bodies in regular waves. For the integral method, with a series of mathematical manipulations, second order drift forces and moments could be easily expressed by distributed sources which could be calculated by source distribution techniques with the assumption that the amplitude of ship motions are small on the basis of the linear 3D frequency theory. For the differential method, drift forces and moments could be expressed by the derivative of velocity potential with respect to space coordinate. Because two bodies would behave as a single body while the clearance is very large, the numerical results of one sphere in such case were given and compared with analytical results of a single sphere which does not involve the effect of free surface. When submerged depth becomes enough large, a good agreement can be reached. Then the integral method was used to predict the second order drift forces and moments of two submerged spheres and spheroids with a small lateral separation distance in waves compared with the numerical results obtained by the differential method and they agree well. By comparison, it indicates the interaction effects between two submerged bodies have a profound influence on the drift forces and moments. In this paper, the forward speed effect on submerged spheres was also considered.
文摘The problem of petroleum safety is closely related to national politics andeconomics security and becomes one of key for discussion in China. The floating oil storage systemhas been proposed as a new facility for Strategic Petroleum Reserve (SPR) in our country. There aresome differences in solving this problem. Although many of domestic research institutions arestudying the project of SPR, the research is separate, and lack of comprehensive consideration, andfails to make a complete and scientific demonstration in many aspects, such as oil storage capacity,selection of storage sites, storage facilities, technologic and economic feasibility, riskassessment, etc. Therefore, no mature and systematic petroleum reserve theories have been formed upto now. Peoples argue the issue of objective of SPR, function, mode, cost, effect, etc. There arestill many bifurcations, so, it is necessary to make more detailed demonstration, and provide somescientific decision-making strategy for the governments. In this paper, several significant problemsare solved, for instance, the option of SPR facilities, the research on the principalcharacteristics of floating oil storage vessels, the a-nalysis of mooring system for oil storagevessels, the design of breakwater and the calculation of failure probability, the risk assessment offloating oil storage system, etc.
