固液連成界面における波動伝播の２次元軸対称解析

抄録

Fluid-structure interaction (FSI) and wave propagation occurred in engineering structure may cause severe damages and result in a deadly accident such as explosion of pipe-lines in a plant. However, how the FSI affects the wave propagation is still not fully understood. From the previous studies, a disagreement was reported between the induced pressure value on the solid-fluid movable interface and predicted value with the classical one-dimensional theory due to the effect of two-dimensional wave propagation. To address this problem, in this paper, two-dimensional axisymmetric simulation of wave propagation across solid-fluid interface with fluid-structure interaction was conducted. The simulation was carried out using ANSYS AUTODYN with Lagrangian solver for solids and Eulerian solver for water. The results showed that the transmitted pressure is attenuated near the tube wall due to the rarefaction wave generated by the tube and fluid's expansion. The averaged pressure distribution after the transmission gradually converged to one-dimensional acoustic theory as the pressure wave propagating away from the interface. Consequently, it was indicated that a transition region for the transmitted pressure existed immediately after the solid-fluid interface to the axial direction until the point of 0.38 in ratio to the inner diameter of the tube. In this region, the transmitted peak pressure can be estimated with normal wave speed in the unconfined fluid in the sight of safety engineering.