I would like to conduct a survey regarding your intuition regarding a question.
The simple idea: instead of turning a thin propeller, I push back a solid disc which opposes the wind much more!
In the following diagram, visible here:
,
we see a wind turbine which sweeps a surface S and a vector V0 perpendicular to S, this is the wind.
On the right, a disk D with the same surface S but full is represented. This disk is like the wind turbine opposed to the wind.
Let us assume that the wind turbine produces each duration T, an energy E1.
Let us also admit that for the same duration T the disk pushed by the wind moves backwards
at speed V1 over a length d and we can recover the energy that the work of the force F which
grows product. This work, therefore this energy, is worth E2=dF
Without doing any calculations Which of E1 or E2 do you think is greater?
