Application of numerical simulation of wind field in offshore domain

• Main Authors: Thanh Nhat TrieuNguyen, 阮趙日青
• Other Authors: Jiun-Jih Miau
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/j9e26r

碩士 === 國立成功大學 === 航空太空工程學系 === 105 === Wind resource assessment is the foundation of wind farm development. The wind farms depend on meteorological conditions, especially the magnitude of the wind speed. Thus, the wind energy is sensitive to the wind speed, to the requirement, a good quality anemometer as wind mast (tower). Unfortunately, there are some errors may occur in the measurements even with proper calibration caused by tower shadow, the nearby obstacles, or even the anemometer tower itself, may cause vibration of the instrument, resulting in measurement error. Previous studies showed that numerical simulation using a mesoscale meteorological model to verify the measurement data. However, the meteorological model has the inherent limitation as the simulation relies on National Centers for Environmental Prediction (NCEP) reanalysis data with relatively coarse resolution, and no data assimilation technique was adopted to improve the accuracy of the simulation. To couple the meteorological model as Weather Research and Forecasting (WRF) with a commercial computational fluid dynamics (CFD) software FLUENT, this study aims to verify the accuracy of measurement data from a wind mast erected offshore near the west coast of Taiwan. The WRF is used to provide velocity profile inlet for unsteady boundary conditions for FLUENT. The results show that FLUENT data output with smooth terrain is closer to measurement data than WRF data. Fluent with higher resolution and strong techniques such as Computer Aided Design (CAD), Finite Volume Method, and many turbulent modeling as Large eddy simulation (LES) and Detached eddy simulation (DES) combined with the appropriate boundary condition, it can provide wind field simulation results in more accuracy. In addition, this study also examined the physical characteristics of a turbulent boundary layer with the CFD methods employed. Particularly, the region near the wall where the viscous effect dominates can affect the results and fidelity of numerical solutions. However, the numerical results indicated that the affected region is rather insignificant in comparison with the entire thickness of the boundary layer.