Introduction
A vessel floating in water reacts to its environment with motion. It has six degrees of freedom, three translational and three rotational. When the floating vessel is attached to appendages, which in this case is mooring lines and risers, these attached slender structures also have effect on how the vessel reacts to the environmental loads. This study is to understand how these effects are analysed. In this chapter, the solution of the uncoupled and coupled analysis is going to be discussed.
Cases for Analysis
Two systems are developed for two cases of analysis. Case I: 500 m water depth Case II: 1000 m water depth
Case I and II varies in water depth to represent the shallow water and deepwater. Comparing the two cases will …show more content…
The dimensions of the FPSO are decided based on a sample ship. The Sea Rose FPSO from White Rose field located offshore Canada is taken as a prototype for the model. Also, information on the White Rose FPSO such as the general arrangement layout of the vessel is obtained from SNAME which can be used as a guide for the form of the …show more content…
The typical mean wind speed for different regions is given by DNV-OS-E301. The wind load has two components: the steady load and time-varying gust wind load. The gust wind is simulated with a standard spectrum. The 100-year mean wind speed at 10 m height in Gulf of Mexico with NPD/ISO gust wind spectrum is used in the analysis. Current
DNV recommends a surface current with 10-year return period to be used in the mooring design analysis. One-hour wind speed at 10 m height can also be used to estimate the wind-generated current velocities with the following equation where statistical data is not available. V_(C_Wind )=0.015∙U_(1 hour,10 m) Equation 3.1
Directions
The non-collinear environment as specified in DNV-OS-E301 is used in the analysis. The wind is at 30° relative to the waves while the current is applied at 45°. The Pierson – Moskowitz spectrum is used for the random waves. For wind, the ISO spectrum is used. The current profile is assumed constant with time. The magnitude and the directions of the wind, wave and current are as shown in Table 3.5 and Figure 3.8
A vessel floating in water reacts to its environment with motion. It has six degrees of freedom, three translational and three rotational. When the floating vessel is attached to appendages, which in this case is mooring lines and risers, these attached slender structures also have effect on how the vessel reacts to the environmental loads. This study is to understand how these effects are analysed. In this chapter, the solution of the uncoupled and coupled analysis is going to be discussed.
Cases for Analysis
Two systems are developed for two cases of analysis. Case I: 500 m water depth Case II: 1000 m water depth
Case I and II varies in water depth to represent the shallow water and deepwater. Comparing the two cases will …show more content…
The dimensions of the FPSO are decided based on a sample ship. The Sea Rose FPSO from White Rose field located offshore Canada is taken as a prototype for the model. Also, information on the White Rose FPSO such as the general arrangement layout of the vessel is obtained from SNAME which can be used as a guide for the form of the …show more content…
The typical mean wind speed for different regions is given by DNV-OS-E301. The wind load has two components: the steady load and time-varying gust wind load. The gust wind is simulated with a standard spectrum. The 100-year mean wind speed at 10 m height in Gulf of Mexico with NPD/ISO gust wind spectrum is used in the analysis. Current
DNV recommends a surface current with 10-year return period to be used in the mooring design analysis. One-hour wind speed at 10 m height can also be used to estimate the wind-generated current velocities with the following equation where statistical data is not available. V_(C_Wind )=0.015∙U_(1 hour,10 m) Equation 3.1
Directions
The non-collinear environment as specified in DNV-OS-E301 is used in the analysis. The wind is at 30° relative to the waves while the current is applied at 45°. The Pierson – Moskowitz spectrum is used for the random waves. For wind, the ISO spectrum is used. The current profile is assumed constant with time. The magnitude and the directions of the wind, wave and current are as shown in Table 3.5 and Figure 3.8