Generating lift at supersonic speeds

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    Lift Supersonic
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Discussion Overview

The discussion revolves around the generation of lift at supersonic speeds compared to subsonic speeds, focusing on the fluid mechanics involved and the implications for wing design. Participants explore the differences in lift generation mechanisms and the challenges posed by drag at high speeds.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant expresses confusion about how lift is generated at supersonic speeds, noting that traditional subsonic airfoils may not be suitable due to reduced viscous effects.
  • Another participant suggests that the angle of attack allows the wing to interact with the air without it being aware of the supersonic conditions.
  • A participant inquires about the specific forces acting on the wing during supersonic flight.
  • It is proposed that lift generation mechanisms are fundamentally similar between supersonic and subsonic speeds, but drag becomes a significant concern at supersonic speeds, leading to the preference for diamond-shaped wings.
  • One participant states that at supersonic speeds, camber has less effect on lift, with angle of attack being crucial, and describes the role of oblique shocks and Prandtl-Meyer expansions in pressure distribution around the wing.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specifics of lift generation at supersonic speeds, with multiple competing views and uncertainties remaining regarding the mechanics involved.

Contextual Notes

Limitations include potential oversimplifications in the descriptions of lift generation mechanisms and the need for wing shapes that accommodate both supersonic and subsonic flight conditions.

flirt
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Im having some trouble understanding how lift is generated at supersonic speed as apposed to subsonic speed. Viscous effects at high speed are greatly reduced and a normal airfoil from subsonic flight is not suitable for such applications.
I have had a good read on wiki and other sites but i can't find much regarding the fluid mechanics of it. I would think there would be a lot on this subject, so how is this lift being generated?
 
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if the wing hits the air at an angle then the air never knows that the wing is supersonic
 
I want to know too. Where are the forces on the wing?
 
Lift is generated more or less the same way - drag is the big issue at supersonic speeds. Drag is why you make diamond shaped wings instead of round wings for supersonic flight.
 
At supersonic speeds, camber no longer affects lift and angle of attack becomes the most important factor. You generate a high pressure below the foil with an oblique shock and the lower pressure above via Prandtl-Meyer expansions. Of course that is an oversimplification because a real supersonic aircraft would have highly swept wings and needs to have a shape that works both supersonically and subsonically.
 

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