In this research paper we investigate, using numerical simulation, film cooling of a horizontal flat plate with its top surface exposed to hot mainstream air. We achieve film cooling by passing a coolant air in the cross-stream direction through a row of cylindrical film cooling holes drilled across the thickness of the flat plate. A parametric study on the complex interaction of film cooling jet and mainstream is critical for understanding the film cooling process, especially in the high free-stream turbulence conditions. To fulfil this objective, we develop a validated 3D virtual simulation framework using ANSYS Fluent. Realizable k − ε (RKE), SST k − ω, BSL k − ω, and Reynold Stress Model (RSM) RANS models are used to predict the effects of turbulence. To optimize the computational cost of the simulation, we reduce the computational domain size by the virtue of symmetry in the geometrical and flow conditions and by modeling the coolant flow without the plenum. We validate the developed numerical model against experimental data available in the literature for Turbulence intensity (Tu) values of 0.5% and 20%, momentum flux (I) and density ratios of 0.156 and 1.05, respectively. In the validation studies, we compare the obtained span-wise and stream-wise numerical thermal field data and report the discrepancies in the predictive capability of the chosen turbulence models. Finally, we draw a few conclusions on the merits and demerits of these models towards the accurate simulation of this application.