# Laws of aerodynamics after breaking the sound barrier

my knowledge of physics is not very extensive, so I hope my question isn't too stupid.

I know that when (for instance) a plane breaks trough the sound barrier, the laws of the aerodynamics change.

But I don't know why because the plane is still being carried by the same air, only it's travelling much faster and this creates a state where the air is (in relation to the plane) much more dense. But I can't make out how this would have an effect on these aerodynamic laws.

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## 1 Answer

It's related to the compressibility of the fluid and the change from laminar flow to turbulent flow.

At high speeds, the air flow around an airplane tends to change from the laminar to turbulent, and the pressure applied is enough to make the air sufficiently compressible.

Read the Laminar vs turbulent flow section of this wikipedia atcile to get a better understanding of laminar and turbulent flow: http://en.wikipedia.org/wiki/Fluid_dynamics

Read the Fluid dynamics section of this wikipedia article and you should get a better understanding of compressibility: http://en.wikipedia.org/wiki/Compressibility

Cheers!

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