다층유동장 해석을 이용한 라이저 VIV의 유체구조 연성해석 프로그램 개발

Abstract

The vibration due to vortex shedding affects on the life time of riser. It is not realistic to simulate the whole riser directly because the length of riser is much larger than the diameter. In this paper, an effective method to analyze the Vortex Induced Vibration (VIV) of riser including Fluid-Structure Interaction (FSI). Several thin fluid regions in various heights are used to present all fluid region. It is assumed that each region does not affects on other regions. Thesolver fluid regions is developed by modifying the pimpleDyMFoam, a standard solver of OpenFOAM. The riser structure is modeled as Linearized Tensioned Beam (LTB). The second and fourth order differential coefficients of riser displacementare calculated by Discrete Fourier Transform (DFT). The riser of each region is moved by the resultant force of the structural and fluid force. For strong coupling of fluid and structure, the fluid and structure are calculated iteratively three or four times in each time step. To verify the present developed solver, simple riser is calculated with eleven 2-D fluid regions.