This paper attempts to analyze performance of the VAWT at different tip speed ratios (TSR), for different number of blades, at different velocities and blade pitch angles. The Double Multiple Steam Tube model was used to find the design parameter of the Giromill Vertical Axis Wind Turbine after analyzing the performance curves at different solidity ratios and tip speed ratios. The turbine with radius 1.12m, chord length 0.11m obtained from the DMST model was used for various 2D computational fluid dynamics simulations. The result showed that the DMST model over-estimates the value of coefficient of performance than the 2D CFD analysis. Simulation results shows the dominance of three-bladed turbine, in performance, over four-bladed turbine at different design parameters, by around 4.3% for same inlet wind velocity of 4m/s. Also, the performance of three bladed wind turbine is found to be better for different wind velocity and it increases at suitable negative blade pitch angle.