Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m in the Liwan 3-1 area of the South China Sea. Firstly, the seake...Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m in the Liwan 3-1 area of the South China Sea. Firstly, the seakeeping ability is acquired in the frequency domain by calculating the hull's hydrodynamics and comparing with a semi-submersible platform. The random wave analysis for 100-year, 10-year and 1-year return periods in Liwan 3-1 distinctly shows lower heave but larger surge and pitch re-sponses of the Truss Spar than those of a semi-submersible. Secondly, 3-hour motions of the Truss Spar are predicted and compared in the time domain under 100-year return period conditions in Liwan 3-1 and the Gulf of Mexico. Thirdly, the hull/mooring line cou-pled and uncoupled models are compared. Finally, the responses of the Truss Spar under 10-year and 1-year return period conditions are assessed. The results reveal that the mooring line damping reflected by the coupled model distinctly decreases the low frequency motion. The maximum heave response for 100-year return period waves is 1.23m and below 0.1m for the case of 1-year return period.展开更多
Eco-sensitivity evaluation is the basis for land development and has practical significance to the establishment of environmentally-friendly economic and social development models. Compared to simple geomorphic region...Eco-sensitivity evaluation is the basis for land development and has practical significance to the establishment of environmentally-friendly economic and social development models. Compared to simple geomorphic regions, complex geomorphic regions are limited by a higher number of eco-sensitivity factors under a land exploitation context. Further still, these factors have complicated spatial characteristics and affect each other. Based on published data, we focused on the city of Qinzhou in Guangxi Zhuang Autonomous Region, China and developed an eco-sensitivity assessment system spanning land ecology, water ecology and plant ecology. A systematic comprehensive assessment of all watersheds was done using qualitative classification, spatial quantitative modeling, remote sensing and GIS technology. We were able to group Qinzhou’s 273 watersheds into three types： high sensitivity areas, medium sensitivity areas and low sensitivity areas. We propose a limit on land exploitation activities in high sensitivity areas and an ecological security network. The methods utilized here can help determine eco-sensitivity characteristics in complex geomorphic regions and with this knowledge governments wil be able to develop robust scientiifc policy to protect regional ecological security.展开更多
基金the supports from National Sci-Tech Major Special Item (No. 2008ZX05056-03)
文摘Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m in the Liwan 3-1 area of the South China Sea. Firstly, the seakeeping ability is acquired in the frequency domain by calculating the hull's hydrodynamics and comparing with a semi-submersible platform. The random wave analysis for 100-year, 10-year and 1-year return periods in Liwan 3-1 distinctly shows lower heave but larger surge and pitch re-sponses of the Truss Spar than those of a semi-submersible. Secondly, 3-hour motions of the Truss Spar are predicted and compared in the time domain under 100-year return period conditions in Liwan 3-1 and the Gulf of Mexico. Thirdly, the hull/mooring line cou-pled and uncoupled models are compared. Finally, the responses of the Truss Spar under 10-year and 1-year return period conditions are assessed. The results reveal that the mooring line damping reflected by the coupled model distinctly decreases the low frequency motion. The maximum heave response for 100-year return period waves is 1.23m and below 0.1m for the case of 1-year return period.
基金the National Water Special Project(2012ZX07101)the National Natural Science Foundation of China(41071085)
文摘Eco-sensitivity evaluation is the basis for land development and has practical significance to the establishment of environmentally-friendly economic and social development models. Compared to simple geomorphic regions, complex geomorphic regions are limited by a higher number of eco-sensitivity factors under a land exploitation context. Further still, these factors have complicated spatial characteristics and affect each other. Based on published data, we focused on the city of Qinzhou in Guangxi Zhuang Autonomous Region, China and developed an eco-sensitivity assessment system spanning land ecology, water ecology and plant ecology. A systematic comprehensive assessment of all watersheds was done using qualitative classification, spatial quantitative modeling, remote sensing and GIS technology. We were able to group Qinzhou’s 273 watersheds into three types： high sensitivity areas, medium sensitivity areas and low sensitivity areas. We propose a limit on land exploitation activities in high sensitivity areas and an ecological security network. The methods utilized here can help determine eco-sensitivity characteristics in complex geomorphic regions and with this knowledge governments wil be able to develop robust scientiifc policy to protect regional ecological security.
