How to Calculate the Tip Speed Ratio of VAWT

Since the invention of the sailing ship in ancient Egypt, mankind has harnessed wind power for transport, leisure, farming and energy generation. Wind turbines evolved from early windmills that ground grain and powered farm water pumps in rural areas. The blades of a vertical-axis wind turbine (VAWT) rotate around a shaft that is perpendicular to the ground; thus, VAWTs require no specific orientation for wind direction. The tip-speed ratio, a measure of the speed of rotation relative to the wind speed, is heavily dependent on blade design.

Calculator
Tape measure

Instructions

- 1
  Note the wind speed in mph for which you need the tip-speed ratio. Divide this figure by 2.24 to convert to meters per second (mps) and make a note of your answer. For example, if the wind speed is 35 mph, the answer is 15.63 meters per second.
- 2
  Note the length of the VAWT blades in feet. If you do not have this figure, measure one blade from hub to tip. Divide the length by 3.28 to convert to meters and make a note of your answer. For example, if the length is 4 feet, the answer is 1.22 meters.
- 3
  Note the rotational speed of the turbine in revolutions per minute (rpm). Multiply the speed by 6.2832 and divide by 60 to convert to radians per second. Make a note of your answer. For example, if the speed is 500 rpm, the answer is 52.36 radians per second.
- 4
  Multiply the rotational speed in radians per second by the length of the turbine blade in meters and divide by the wind speed in meters per second. Make a note of your answer. For example, if the rotational speed is 52.36 radians per second, the blade length is 1.22 meters and the wind speed is 15.63 meters per second, the answer is 4.09.
- 5
  Check each step of the calculation. Record the result, which is the tip-speed ratio for your VAWT.

How to Insulate a Basement in Michigan

Dense Blown Insulation Vs. Foam Insulation

Energy Efficient Homes