Effects of hypersonic speed on the behaviour of normal shocks

In summary, there is a lot of discussion about the effects of oblique shock on hypersonic flow, but not much is mentioned about the normal shock at high Mach numbers. This is because the normal shock still follows the same rules as before and does not have significant interactions with a body. Both oblique and normal shocks can be affected by the boundary layer, known as the viscous-inviscid interaction or hypersonic viscous interaction. At high Mach numbers, molecular dissociation can also play a role in changing the gas quantity and species.
  • #1
TL;DR Summary
What happens to normal shocks at hypersonic speed
I am learning about hypersonic flow now and there seems to be a lot of discussion about the effects on oblique shock as the Mach tends to be very large.
I was wondering what happens to the normal shock as the Mach number tends to be high and I can't seem to find anything about it. Is it because it is not possible to have a normal shock at hypersonic speeds?
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  • #3
You don't find much on it because nothing happens. They still obey all of the same rules they did before, and since they aren't attached to a body, you don't have some of the fun interactions you can get with oblique shocks.

For that matter, so do oblique shocks. The issue is just that oblique shocks tend to get so close to the surfaces generating them that the effect of the boundary layer can no longer be ignored and the inviscid approximation typically used for supersonic flows breaks down. This is called either the viscous-inviscid interaction or the hypersonic viscous interaction.
  • #4
Does anything interesting happen with regards to molecular dissociation actually changing the gas quantity/species through the shock or anything like that, or is the energy still not quite high enough for that?
  • #5
It sure can but it all depends on Mach number and ambient conditions. You can be hypersonics with or without that.

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