In the present study, numerical investigation is performed on a H-Darrieus wind turbine under turbulent flow conditions. The turbine contains 3 rotor foils, NACA-0012 with 0° angle of attack, placed at 120° apart from each other, with rotor casing close to the airfoil. The inlet is considered to be velocity inlet and outlet to be pressure outlet while the side walls are given symmetric boundary conditions, as the walls are considered to be infinity. The airfoils are rotating at 150 R.P.M. The meshing is done using Hexa-Dominant element to capture the flow very precisely and inflations are given wherever necessary. The problem is considered as two-dimensional, and the analysis of the model under the condition of turbulent flow is modeled using S.S.T-k-ω turbulence model. Simulation is performed using finite volume solver Ansys Fluent 2019-R2. The performance of the H-Darrieus wind turbine is analyzed, by varying the wind speed and turbine rotational speed. The further investigations are performed by comparing the flow characteristics between a stationary and rotating turbine. The results are analyzed by plotting the streamlines, velocity and pressure contours. The flow is analyzed at 6m/s, 8m/s, 10m/s as inlet freestream velocity and also by varying the rotor dimension, which was initially made as small as possible. The results indicate that the wind speed and rotational speed significantly influences the significant aero characteristics of the model of the wind turbine. The present results are validated and are in good accord with the benchmark results available in literature. © Published under licence by IOP Publishing Ltd.