Abstract The drag and added mass coefficients of a flexible pipe undergoing vortex-induced vibration (VIV) in an oscillatory flow are investigated experimentally with maximum reduced velocities ranging from 4 to 7.9 and Keulegan-Carpenter (KC) numbers ranging from 10 to 178. The strain responses are measured by fiber bragg grating sensors. By using displacement reconstruction and inverse analysis methods, displacement response and hydrodynamic force are identified. Then, through least square method, drag and added mass coefficients are extracted. The results show that drag coefficient varies with both the maximum reduced velocity and KC number. It is stable in cases with large KC numbers but significantly amplified in the cases of small KC numbers. The maximum value of the drag coefficient can reach 3.5 at kC

中文翻译：

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在振荡流中经历涡激振动的挠性管的阻力和附加质量系数

摘要 通过实验研究了在振荡流中经受涡激振动 (VIV) 的挠性管的阻力和附加质量系数，最大折减速度范围为 4 到 7.9，Keulegan-Carpenter (KC) 数范围为 10 到 178。应变响应由光纤布拉格光栅传感器测量。通过位移重建和逆分析方法，确定了位移响应和水动力。然后，通过最小二乘法，提取阻力和附加质量系数。结果表明，阻力系数随最大折减速度和 KC 数而变化。在 KC 数较大的情况下它是稳定的，但在 KC 数较小的情况下会显着放大。kC时阻力系数最大值可达3.5