Apparent wind in knots and degrees. Note that a number of additional factors come into play when converting the measurements from the masthead anemometer into the true wind if a high degree of accuracy is required, including the following: In the presence of a current, the true wind is considered to be that measured on the craft drifting with the water over the bottom, and wind with respect to the sea bed as the "ground" or "geographical wind". The apparent wind on board (a boat) is often quoted as a speed measured by a masthead transducer containing an anemometer and wind vane
Tip-speed ratio wind turbine to be directly connected to a transmission system. However, from the figure above, we can see that the power coefficient is a function of the tip-speed ratio. By extension, the efficiency of the wind turbine is a function of the tip-speed ratio. Ideally, one would like to have a turbine operating at the maximum value of formula_7 at all wind speeds. This means that as the wind speed changes, the rotor speed must change to such that formula_9. A wind turbine with a variable rotor speed is called a variable speed wind turbine. Whilst this does mean that