An interface control principle is proposed for unsteady fluid-structure in- teraction (FSI) analyses. This principle introduces a method of explicitly controlling the interface motion in the temporal direction to minimize the residual force on the interface, which is defined as the discrepancy between the fluid and structural forces. The interface model is constructed using a data-driven approach that involves sparse identification of nonlinear dy- namics with control to evaluate the residual force. The interface model is subsequently subjected to control theory in order to minimize the residual force. Following the convergence of the residual force, the interface state is controlled to be that of the original unsteady FSI system. The fluid and structural simulations can be conducted independently without communication, as the interface state information is predetermined as inputs for each system. The proposed method is applied to the vortex-induced vibration (VIV) of a cylinder at a Reynolds number of 150 under several reduced velocity conditions corresponding to the lock-in regime with limit-cycle oscillations. The results demonstrate that the residual force is sufficiently minimized in time, and when the residual force is close to zero, the predicted fluid force and structural displacement of the VIV show good agreement with the reference FSI simulation.

翻译：本文针对非定常流固耦合分析提出了一种界面控制原理。该原理引入了一种在时间方向上显式控制界面运动的方法，以最小化界面上的残余力，该残余力定义为流体与结构力之间的差异。界面模型采用数据驱动方法构建，该方法涉及含控制的非线性动力学稀疏辨识，以评估残余力。随后对界面模型施加控制理论以最小化残余力。在残余力收敛后，界面状态被控制为原始非定常流固耦合系统的状态。由于界面状态信息已预先确定为各系统的输入，流体与结构模拟可独立进行而无需通信。所提方法应用于雷诺数为150的圆柱体涡激振动，在对应极限环振荡锁定区的多种折合速度条件下进行了验证。结果表明，残余力在时间上被充分最小化，且当残余力趋近于零时，预测的涡激振动的流体作用力与结构位移与参考流固耦合模拟结果高度吻合。