One-way flap-valves for parafoil ram-air inlets are gaining in popularity (eg. HQ Hydra). There is a far larger AWES application possible for the flap-valve mechanism in large kite meshes.

Imagine a kite skin that is composed of flap-valves. It would act as a one-way gate to flow. In a turbulent wind field, the valves can sort scrambled flow into a coherent force polarity. A simple way to make a valved-skin is with a back-up mesh covered with fabric flaps on one side. The mesh supports the flaps in closed mode, and the flaps open freely when the flow reverses. A similar case is a kite with an elastic aft-bridle to comply with gusts.

A particular megascale application opportunity is to tap the Intertropical Convergence Zone (ITCZ). While its horizontal flow is often weak, its vertical instability is full of energy. A megascale tent-like dome made of an open mesh of flap-valve surfaces could self-sustain flight and aggregate wind-power. The thermals within its area would propel it upward, while the down-drafts would by-pass. The lattice must span the characteristic dimension of the turbulence cells to ensure the presence of lifting air. Note that with rising air, the greatest Drag-to-Weight ratio is favored. The lifting force is already in the flow.

This idea has slowly emerged to try to solve ITCZ AWES design challenges. Its rather grand to be able to contemplate an airborne lattice-work that thrives in a stormy vertical convection fields by the simplest of embodied logic

• CC BY NC SA        ~Dave Santos         1March2013              AirborneWindEnergy/message/8726 

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• Terms and aspects:   
  • ITCZ
  • One-way flap-valves
     
• Related links and concepts:
  •  http://en.wikipedia.org/wiki/Lapse_rate
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