Machine-translated by Google. Questions are authored in English.
Top

Discussion

The central difficulty of subsonic wind-tunnel testing is that

  • A.Forces are too large to measure
  • B.Reynolds and Mach numbers cannot both be matched
  • C.Models cannot be built accurately enough
  • D.Air cannot be made to flow steadily

Answer: B

A small model needs a higher speed to match the Reynolds number, but raising the speed also raises the Mach number past the value being simulated. Escaping the conflict means changing the density or viscosity instead, which is why pressurised and cryogenic tunnels exist.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.