An Exploration of Properties of Circulation Conserved Scheme and its Comparison with Other Viscous Diffusion Models

• Main Authors: Yung-Yu Chen, 陳永昱
• Other Authors: Mei-Jiau Huang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/11566202543623186149

碩士 === 國立臺灣大學 === 機械工程學研究所 === 90 === This thesis investigates will discuss the basic properties about Circulation Conserved Scheme (CCS) by performing numerical simulations. Because CCS does the correction to Viscous Diffusion Method (VDM), results of the two methods will also be compared and discussed. The stability, convergence and accuracy will be the issue of interest. Factors that dominate stability and convergence include the number and density of vortex particles, and size of material surface that conserves circulation in CCS. Two axisymmetrical flow fields, the Gaussian distributed and disk patch vorticity field, will be simulated and compared and discussed by using VDM, CCS and Leonard vortex blob methods. Simulation results show that the growth of core sizes of vortex particles is slower in all methods employing the viscous diffusion velocity compared to Leonard's. The CCS is more accurate than VDM methods, but because less stable as the the size of material surface are large, choosing material surfaces of zero size can not only solve this problem, but also significantly reduces the computations, and does little harm on the accuracy.