Because stress isn't energy. A book sitting on a table puts a stress on the table, but no energy is being expended.
for your example, I agree since the stress is constant over time.
For Darrieus type turbines, the stresses vary during each turn. You do have a notion of time. It is possible to transform constraints into additional energy recovery.
http://www.cyberquebec.ca/_layout/?uri=http://www.cyberquebec.ca/normandajc/
To calculate the structure of the mast, this force is taken into account
Coef 1/2 rho S V^2
The coefficient is close to the one defined by Betz.
60% of the kinetic energy of the wind can provide energy, but 60% of the kinetic energy of the wind creates stress. Why is it not possible to transform...
Betz's theory is absolutely correct. It is calculated in relation to kinetic energy.
Using a relative velocity which is the combination of the rotational speed and the fluid velocity creates an induced force on the profile. Part of this force associated with the radius creates a driving torque...
I don't understand why it is impossible to transform constraints into additional energy recovery. It is potential energy that we transform into kinetic energy. Large wind turbines are stopped when the constraints are too high. That is, when the potential energy is too high. It is not the kinetic...
The normal force on the hydrofoils allows the sailboat to be lifted and makes it possible to counter the tilt. By this trick, we transform potential energy (stress on the keel) into kinetic energy.
"Not every law is created equal"
If we consider a trolley with a vertical plate exposed to the wind. If the trolley is free and without any resistance, it will move at wind speed and the vertical plate is not stressed.
If the wheels of the trolley are welded, the trolley speed is zero and the...
I never said that the keel allows you to speed up. On the other hand, replacing the keel with hydrofoils, allows for better performance on the sailboat.
"In fact, the turbine 'converts', if you will, this axial force in a torque, so the bending stress is directly related to the torque and rpm of the blade."
For a horizontal axis turbine, the bending stress is constant over time if the fluid velocity is constant. This is not the case for a...
How would this work? Because this is simply not true:
If I understand a sailboat equipped with hydrofoil can not go faster. A glider that goes against the wind cannot go forward. Yet this is possible because it is the relative speed that is the key to the mystery. For a Darrieus turbine, the...
If you put a wind turbine on a moving platform, you must consider the speed of the fluid the turbine receives. The relative velocity, not the velocity relative to the ground, should be considered.
The advantage of a Darrieus type turbine is that the stresses in the arms vary alternately from compression to extension during each revolution. The conversion system is a connecting rod and crank system. Instead of the piston moving, the crankshaft moves. The profile almost describes the path...