IB Physics IA idea · Energy and the environment
IB Physics IA idea: does turbine power rise as the cube of wind speed?
Double the wind and you should get eight times the power. Measure how well a small turbine follows that.
These ideas are starting points, not an IA to copy. Never copy an idea blindly: make the question, method and analysis your own, and check your plan with your teacher.
Example research question
How does the electrical power from a small model wind turbine into a matched load depend on wind speed from 2 to 6 m/s at six or more fan distances, and how does the power coefficient compare with the Betz limit?
Change the system, the range or the method so the question is yours. Check it against the research question checklist in our Physics IA guide.
Variables
- You change
- wind speed from a fan, 2 to 6 m/s (6 or more distances)
- You measure
- electrical power into a matched load, 0.1 to 20 mW
- You keep the same
- rotor and blade angle
- load resistance
- fan setting
- measurement position
Method
Place a small model turbine in front of a fan at different distances and measure wind speed with an anemometer. Record voltage across the load and compute power.
Data analysis
Plot power against v^3; the gradient is half rho A C_p. Find C_p, compare with the Betz limit 0.59 and discuss rotor losses and flow non-uniformity.
How it works
You change Wind speed (m s⁻¹) and measure Electrical power (mW) in Model wind turbine and fan, keeping Load resistance, Rotor and blades, Turbine position the same. Expect a graph of Power P / mW against Wind speed v / m s⁻¹: Power climbs faster and faster with wind speed.
Make it yours
Change the pitch angle and find the best blade setting.
Safety
Take care with: sharp tools, mains or high-voltage electricity.
Rotating blades: guard the rotor; keep hair clear.
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