[nauman maldar]

Hello .. My question is related to the CFD simulation of ocean current turbines...I am trying to simulate a turbine in the flow velocities of 1 to 1.5 m/s...when i run the simulations and after completion when i calculate the tip-speed ratio for the turbine simulations for different velocities, all the values i get are in the range of 0.88-1 (like 0.87,0.89,0.92,0.97) ..even when the flow speed is as low as 0.5 m/s and also when its as high as 1.4 m/s....but in most of studies i see the graphs that have a uniform tip-speed ratio like 0.6,0.7,0.8,0.9,1 (with a uniform fixed interval of 0.1)... how do they get to control the tip-speed ratios so accurately? do they apply a fixed angular velocity of the turbine blades and then give the inlet velocity depending upon the tip-speed ratio value ? or is there any other way to control it.. ?