Участник:Эйхер/Песочница: различия между версиями
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Строка 112:
A vehicle with a blade rotor mechanically connected to the wheels can go both directly against the wind and downwind faster than the wind. In the first case (going upwind) the rotor is used as a wind turbine driving the wheels. In the second case the rotor is used as a propeller (airscrew) and is driven by the wheels. The source of energy in any case is the speed difference between two media - the air and the Earth.
It was shown by Ganuaa ''et al'' that with 100% efficiencies (i.e. no losses in the drivetrain, on the wind turbine or on the propeller) and with no drag other than associated with energy harvesting (e. g.
In both cases the two media travel in the same direction relative to the vehicle - backwards. In the case of going upwind the air is travelling faster than the Earth and in the case of going downwind faster than wind the Earth is travelling faster relative to the vehicle. For a given force imparted by a medium to the vehicle the power delivered to or gained from the meduim is directly proportional to the velocity of the medium relative to the vehicle. Therefore in accordance with the law of conservation of energy in order to sustain the motion the vehicle must harvest the power from the medium that moves faster relative to the vehicle and to deliver power to the slower medium.
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