To determine the speed of the wind on a Savonius wind turbine based on the speeds of vehicles passing by, we need to consider the relative wind speed created by the movement of the vehicles.
Assuming the vehicles are moving at a constant speed of 100 km/h (or 27.8 m/s), and we want to find the wind speed at the turbine's rotor diameter, we can use the concept of wind speed ratio.
The wind speed ratio is the ratio between the effective wind speed experienced by the turbine and the actual wind speed. It can be calculated using the following formula:
Wind speed ratio = (Turbine rotor speed) / (Vehicle speed)
In this case, the turbine rotor speed is determined by the circumference of the rotor, which is given by:
Circumference = π × Diameter Rotor speed = Circumference × Angular velocity
Now, assuming the Savonius wind turbine has a rotor diameter of 0.5 meters and considering a typical angular velocity of 2π radians per second, we can calculate the rotor speed:
Circumference = π × 0.5m = 1.57m Rotor speed = 1.57m × 2π rad/s = 9.87 m/s
Finally, we can calculate the wind speed ratio:
Wind speed ratio = 9.87 m/s / 27.8 m/s ≈ 0.354
Therefore, the speed of the wind experienced by the Savonius wind turbine, based on vehicles moving at 100 km/h and a rotor diameter of 0.5 meters, would be approximately 35.4% of the vehicle speed or 9.87 m/s.