This report provides a detailed analysis of wind turbine aerodynamic theory and simulation. It begins with an introduction to wind energy extraction, focusing on different types of wind turbines, including horizontal and vertical axis designs, and the major parameters used in wind energy calculations. The report then reviews existing literature on wind energy calculation methodologies and the Blade Element Momentum (BEM) technique. The methodology section explains the BEM method and momentum theory in detail. A significant portion of the report is dedicated to 2D and 3D CFD simulations, including results and discussions for both. The report also presents BEM results and compares them with simulation results, offering insights into the aerodynamic performance of wind turbines. The conclusion summarizes the findings and highlights the importance of aerodynamic principles in wind turbine design and efficiency. This report is a comprehensive study of the aerodynamic aspects of wind turbine technology.