Abstarct: Wind turbines are highly complex structures for numerical flow simulation. Today, developments and increasing use of wind energy in the world has created a demand for progressively more accurate and efficient models for wind applications. Wind turbine wakes have significant effects on decreasing the produced power and blades fatigue loads, thus, the study on wake turbulence has great importance in wind turbine simulations. Actuator line model (ALM) is one of the most accurate models for characterization of the flow field and the turbulent wakes created by the turbines. ALM does not require boundary laxyer resolution and is therefore significantly more efficient than the fully-resolved computations. ALM can accurately simulate the wakes of wind turbines operating in a flow field without any need to create the turbine CAD model and just by using turbine parameters. In this thesis, the ALM with a novel gaussian spreading width baxsed on the blade's aspect ratio, local chord length and grid resolution, is implemented in openFOAM to be employed in combination with large eddy simulation (LES) as an effective numerical tool to carry out the study of the EU project ''MEXICO'' turbine. Results including wake study, blade forces and performance parameters, are validated against the experimental measurements and it is observed that the ALM results agreed fairly well so that the turbine's thrust had 9.9% difference while the torque and power showed difference by 10.3 and 1.1% respectively.