【摘 要】
：
Flow-induced vibration (FIV) of a group of long,flexible cylinders involves a complex interaction between fluid and structures.Although a substantial number of studies have been devoted to assessing FIV response behaviours,fatigue damage features of stagg
【机 构】
：
State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 30007
论文部分内容阅读
Flow-induced vibration (FIV) of a group of long,flexible cylinders involves a complex interaction between fluid and structures.Although a substantial number of studies have been devoted to assessing FIV response behaviours,fatigue damage features of staggered flexible cylinders are not fully understood.Moreover,the wake-induced flutter constitutes an intricate hydrodynamic behaviour that frequently occurs when one cylinder is in the vicinity of another one.Unfortunately,existing studies on the fatigue damage caused by wake-induced flutter are incapable of achieving better results.This paper,therefore,estimates the FIV fatigue damage of two staggered flexible cylinders with an aspect ratio of 350 and a mass ratio of 1.90 based on normal S-N curves according to Det Norske Veritas (DNV)regulations.Twelve staggered cases (cross-flow spacing ratios of 2.0,3.0,4.0,and 6.0 and in-line spacing ratios of 4.0,6.0,and 8.0) are discussed for comparison,and fatigue damage caused by wake-induced flutter is thoroughly considered.Fatigue damage results indicate that the variation of the cross-flow (CF) spacing ratio has a greater influence than that of the in-line (IL) spacing ratio on the CF fatigue damage of the upstream cylinder.Lower IL fatigue damages of the upstream cylinder are observed when reduced velocity Vr≥ 15.03 due to the wake flow patterns with different IL spacing ratios.Moreover,wake interference,especially wake-induced flutter,predominates the fatigue damage characteristics of the downstream cylinder.When Vr=8.77-11.27,wake-induced flutter enhances the IL fatigue damage of the downstream cylinder and slightly affects that of the upstream body.Furthermore,wake-induced flutter causes considerable IL fatigue damage disparity between the two staggered cylinders by suppressing the IL fatigue damage of the upstream cylinder when Vr≥20.04.
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