Numerical Simulation of Turbulent Diffusion over Non-homogeneous Terrain

• Main Authors: Tsung-Han Tsai, 蔡宗翰
• Other Authors: 謝正義
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/92279828809483443589

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 94 === The present study is based on a two-dimensional turbulence diffusion model, in which the passive-mixing in neutral atmosphere boundary layer is simulated. In the numerical model, two-dimensional standard k-ε turbulent model is employed to simulate the flow field. The passive transportation of water vapor passing by solid structure and permeable structures is discussed. The parameters in the present numerical model include horizontal wind velocity, vertical wind velocity, total pressure, turbulent kinetic energy, turbulent dissipation rate, turbulent viscosity, and water vapor concentration. In the research, forest density is classified into three levels: high, medium and low. The result shows that the characteristics of flow field in high and medium dense forest are obviously different from that in low dense forest. The height of mixing layer and the aggregate value of vapor concentration grow with the forest density. Furthermore, density levels of the forest also cause different diffusion effect in the flow field.