The influence of upstream and downstream flow and its effect due to the operating wind turbine at various wind speeds are important in considering the wind turbine spacing in a turbine park. In this research paper study is made towards what extent the wind turbine with a rotor diameter D, influences the flow in upstream and downstream computationally. The reduction in the maximum power coefficient strongly depends on the distance between the turbines and the operating condition of the upstream turbine. Presently, the standard power curve measurements assumes that the turbine wind condition has negligible influence on the flow at two times the rotor diameter upstream. However, the upstream effect due to the operating wind turbine beyond two times the rotor diameter (2D) leads to the consequences of the power estimate for any given turbine and this leads to the wind farm for total power production. Similarly, the downstream of the operating wind turbine is equally important in terms of the power production of the wind turbine park. Numerical simulations are performed on a wind turbine with a rotor diameter of 80 m and the tower height of 100 m with various blade pitch angles. The NACA-63-425 aerofoil is selected for the blade profile in this analysis. The result shows that the influence of the pitch angle will not influence much difference in upstream flow and much difference in the downstream flow. However, at the distance more than two times (> 2D) of the rotor diameter upstream around 3% change in the velocity is observed when compared to the free stream velocity. In the downstream, velocity the influence of operating wind turbine extends up to 6.5D for a velocity of 20m\s. © 2017, Institute of Advanced Scientific Research, Inc. All rights reserved.