Numerical Simulation and Analysis of the Cavity Flow Field at Variously Geometric Cylinder and Rearrangement

• Main Author: 高江俊
• Other Authors: 莊書豪
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/97264001825762954823

碩士 === 國立中興大學 === 機械工程學系 === 92 === Abstract In this study, the numerical simulation and analysis method of a computational fluid dynamics (CFD) code of PHOENICS and according to SIMPLEST algorithm with the Hybrid Scheme was used to calculate the two-dimensional cavity flow field and these influences of the contour, the characteristic scale, the rearrangement of variously geometric cylinder upon the cavity flow field, which had be described and analyzed in the qualitative analysis of these physical properties of the cavity flow field. The simulated parameters in this study were described as follows: inlet work fluid of free stream velocity (U∞), length/depth ratio of cavity (L/D), shape of geometric cylinder, horizontal distance between geometric cylinder and cavity (XL.E/L), vertical distance between geometric cylinder and cavity (H/D). From the calculating results of the numerical simulation and analysis show that the upper shear layer and inner recirculation zone was effected by these factors of the region of wake flow, the vortex structure, the turbulent strength, and the vortex street of variously geometric cylinder, when the position of geometric cylinder was especially located near the upstream corner of the cavity. The phenomena of strong interaction between the vortex street, turbulent effect of geometric cylinder wake flow and unstable self-sustaining oscillation of the cavity shear layer was shown, when the vertical and horizontal distance between geometric cylinder and cavity are H/D≦1.0, XL.E/L≦0.7, respectively. From the present study and the phenomena of the flow field show that the upper shear layer and inner recirculation zone structure of cavity are effected by the wake flow, vortex shedding, vortex period of geometric cylinder flow field, and vertical and horizontal distance of between geometric cylinder and cavity. The findings herein establish a fundamental numerical study of two-dimensional cavity flow field at variously geometric cylinder and rearrangement and a basis for further analysis of the associated cavity flow for more complicated cylinder arrangement.