# Why is the flow ahead of a shock wave chaotic?

Here is the image of a shock wave on a cone in a small supersonic wind tunnel, the white lines are the condensations formed in the test chamber due to flow expansion.

Why are the condensations so chaotic ahead of the shock wave?

I know that the flow shouldn't fall down on the cone but still, why is it so chaotic?

Note: the chamber is 4-5 cm long.

• turbulence at supersonic speed does not travel upstream so the turbulence must be created by the wind tunnel design would be a good addition to the answer. – Koyovis Aug 25 '19 at 6:19