Fluid–Structure Interaction Numerical Simulation of Bridge Wind-Induced Vibration Based on CV Newmark-β Method

Abstract

Two kinds of numerical solution of differential equations were first introduced to solve the problem of wind-induced vibration of bridge structures. Fluid-structure interaction (FSI) numerical simulation of a streamlined bridge section was realized using ANSYS Fluent as the computing platform and embedding user-defined function (UDF) in Fluent. Theoretical analysis indicated that the displacement gained by the FSI calculation model, where the grids near the bridge section were driven by conventional Newmark-beta (β) program embedded in UDF, differs from that of grid motion updated in Fluent. A corrected velocity method (i.e., CV Newmark-β) was proposed in this work to eliminate such an error. The corresponding FSI simulation model was then set up through the abovementioned method. For a concrete bridge section, the FSI simulation under low and high wind speeds was obtained by the models set up using conventional Newmark-β and CV Newmark-β programs. Result showed that the displacement time history curves obtained using different calculation models are consistent while the bridge section takes a small amplitude motion. The error from the displacement of conventional Newmark-β program and actual grid motion is small. In addition, the error of the displacement mismatch effect between this algorithm and the real motion of the grid can be ignored under low wind speed. While the bridge section takes a large amplitude flutter motion, the disparities of the displacement time history curves obtained using different calculation models are large. The error of the displacement mismatch effect between the conventional Newmark-β algorithm and the real motion of the grid must be considered under high wind speed. The displacement gained using the FSI calculation model set by the CV Newmark-β program is consistent with the real motion displacement of the grid motion updated in the Fluent program whether under low or high wind speed. Therefore, such a mismatch effect must be considered to establish a reasonable FSI calculation model while taking the numerical simulation of bridge flutter.