附属管线对隔水管涡激振动影响的数值模拟研究

涡激振动现象会引起海上钻井平台隔水管发生结构失稳和疲劳破坏。针对附属管线安装位置对隔水管的涡激振动影响开展了三维数值模拟，采用CFD大涡模拟计算方法，对不同来流角度α、直径比d/D和间距比G/D情况进行数值模拟，得到隔水管所受的升力和阻力变化情况并对其进行频谱分析。模拟结果表明:隔水管所受的升力和阻力对来流角度的变化很敏感，阻力系数CD和升力系数均方根CrmsL随来流角α的增大而减小，并在α值为30~45°范围内降至最低；用来表征隔水管后方漩涡脱落频率的St数随α的增大略有增大，但总体稳定保持在较低值范围。根据模拟结果，附属管线在直径比d/D值应在0.2~0.3范围内，间距比G/D值在0.3~0.4范围内的布置方式对隔水管涡激振动的抑制效果最为理想。

Numerical simulation on influence of affiliated pipes to vortex-induced vibration of drilling riser

The phenomenon of vortex-induced vibration will cause the structure instability and fatigue failure of drilling riser on offshore drilling platform. The three-dimensional numerical simulation was performed to study the effect of the affiliated pipes on the vortex-induced vibration of drilling riser. The numerical simulation was conducted with different parameters, such as incoming flow angle α, diameter ratio d/D, spacing ratio G/D by using the CFD technique through Large Eddy Simulation (LES). The change of lift force and resistance received by the drilling riser was obtained and analyzed by spectral analysis. The results showed that the lift force and resistance received by the drilling riser are very sensitive to the change of incoming flow angle, both the resistance coefficient CD and the root mean square of the lift force coefficient CrmsL decrease with the increase of incoming flow angle, and decrease to the lowest when α is in the range from 30° to 45°. The number of St used to characterize the vortex shedding frequency behind the drilling riser increases slightly with the increase of α, but remained stable in the range of lower value overall. It was considered that the arrangement method of the affiliated pipes with the diameter ratio of d/D in the range from 0.2 to 0.3 and the spacing ratio G/D in the range from 0.3 to 0.4 is the best to suppress the vortex-induced vibration of the drilling riser.