深水立管两向自由度涡激振动的数值分析

对更加符合实际情况的两向自由度涡激振动进行数值分析。研究四种不同质量比(m*=14.45，8.30，3.50和m*=1.87)情况时，流向振动与横向振动幅值和频率之间的关系。结果表明，在大质量比（m*=14.45，8.30）时，流向振动频率基本可以看做横向振动频率的2倍，并且流向振动幅值相对于横向振动幅值来说可以忽略不计，符合现有实验研究结果；当质量比较小（m*=3.50，1.87）时，顺流向振动幅值并不能被忽略，尤其在顺流向处于锁频时。两向振动的主频率基本维持2倍关系，但是除主频率外还具有相同或相似的振动频率。

Numerical analysis of two-degrees-of-freedom VIV of deepwater riser

For the more realistic case, a numerical method was used to analyze the two degrees of freedom vortex-induced vibration(VIV). To study the relationship between the in-line vibration frequency and the cross-flow frequency for four mass ratios (m*=14.45,8.30,3.50 and m*=1.87). The results show that the in-line frequency will be twice of that in cross-flow direction when the mass ratio m*=14.45 and 8.30, the response amplitude in in-line direction can be neglected compared with that in cross-flow direction, which is in accordance with the experimental results. When the mass ratio m*=3.50 and1.87, the in-line response amplitude can’t be neglected, especially when the in-line vibration is under a lock-in situation. The main frequency also remain the same relationship, but except for the main frequency, there are the same or similar frequency components.