The semi-submersible with three circular columns is an original concept of efficient multifunctional platform, which can be used for marginal oil, gas field, and Floater of Wind Turbines (FOWT). However, under certain flow conditions, especially in uniform current with specific velocities, the eddies will alternatively form and drop behind columns, resulting in the fluctuating lift force and drag force. Consequently, the semi-submersible will subject to the Flow-Induced Motions (FIM). Based on the Detached Eddy Simulation (DES) method, the numerical studies were carried out to understand the FIM characteristics of the three-column semi-submersible at two different parameters, i.e., current incidences (0°, 30°, and 60°-incidences) and reduced velocities ($4\le U_r\le 14$). The results indicate that the lock-in range of $6\le U_r\le 10$ for the transverse motions is presented, and the largest transverse non-dimensional nominal amplitude is observed at 60°-incidence, with a value of $A_y/D=0.481$. The largest yaw amplitude $A_{yaw}$ is around 3.0° at 0°-incidence in the range of $8\le U_r\le 12$. The motion magnitude is basically the same as that of a four-column semi-submersible. However, smaller responses are presented compared to those of the three-column systems revealing the mitigation effect of the pontoon on FIM.

三圆柱半潜器是高效多功能平台的独创概念，可用于边缘油气田和风力涡轮机浮子（FOWT）。然而，在一定的流动条件下，特别是在特定速度的均匀流中，涡流会交替形成并落在柱子后面，导致升力和阻力波动。因此，半潜器将受到流动诱导运动 (FIM) 的影响。基于分离涡模拟 (DES) 方法，进行数值研究以了解三柱半潜器在两个不同参数下的 FIM 特性，即电流入射角（0°、30°和 60°-发生率）和降低的速度（$4\le {你}_r\le 14$）。结果表明，锁定范围为$6\le {你}_r\le 10$ 对于横向运动，最大横向无量纲标称振幅在 60° 入射处观察到，值为 ${\mathrm{一种}}_{是}/D=0.481$. 最大偏航幅度${\mathrm{一种}}_{是\mathrm{一种}瓦}$ 在 0° 的入射角范围内约为 3.0° $8\le {你}_r\le 12$. 运动幅度与四立柱半潜器的运动幅度基本相同。然而，与显示浮桥对 FIM 的缓解作用的三柱系统相比，呈现的响应较小。