The aeroelastic phenomenon of limit-cycle oscillations (LCOs) is analysed using a projection-based reduced-order model (PROM) and Navier–Stokes computational fluid dynamics (CFD) in the time domain. The proposed approach employs incompressible Navier–Stokes CFD to construct the full-order model flow field. A proper orthogonal decomposition (POD) of the snapshot matrix is conducted to extract the POD modes and corresponding temporal coefficients. The POD modes are directly projected to the incompressible Navier–Stokes equation to reconstruct the flow field efficiently. The methodology is applied to a plunging cylinder and an aerofoil undergoing LCOs. This scheme decreases the computational time while preserving the capability to predict the flow field accurately. The ROM is capable of reducing the computational time by at least 70% while maintaining the discrepancy within 0.1%. The causes of LCOs are also investigated. The scheme can be used to analyse non-linear aeroelastic phenomena in the time domain with reduced computational time.

中文翻译：

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通过基于投影的降阶模型进行时域非线性气动弹性分析

使用基于投影的降阶模型 (PROM) 和 Navier-Stokes 计算流体动力学 (CFD) 在时域分析极限循环振荡 (LCO) 的气动弹性现象。所提出的方法采用不可压缩的 Navier-Stokes CFD 来构建全阶模型流场。对快照矩阵进行适当的正交分解 (POD) 以提取 POD 模式和相应的时间系数。POD 模式直接投影到不可压缩的 Navier-Stokes 方程，以有效地重建流场。该方法适用于一个俯冲气缸和一个正在经历 LCO 的机翼。该方案减少了计算时间，同时保留了准确预测流场的能力。ROM 能够将计算时间减少至少 70%，同时将差异保持在 0.1% 以内。还调查了 LCO 的原因。该方案可用于分析时域中的非线性气动弹性现象，减少计算时间。