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How are shockwaves able to refract? As said in this,

When two shock waves collide, they interact with each other and produce complex patterns of compression, rarefaction, and reflection. The resulting behavior depends on the strength, speed, and direction of the shock waves, as well as the properties of the medium they are traveling through.

I understand how they might be able to pass through each other, but why would they refract? Light and optics are a bit different than aerodynamics at supersonic speeds I'd imagine.

Also, refracting meaning when a shockwave refracts off of another shockwave. I assume they have to be different densities to refract off of each other.

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    $\begingroup$ I'm not the down voter, but while the topic is interesting, as a Stack Exchange question this is currently low quality. If you hold a cursor over the down vote arrow the tooltip suggestion for that action is "This question does not show any research effort... Downvoting is exactly the correct action when a question does not demonstrate any effort to look for an answer first, before posting here. $\endgroup$
    – uhoh
    Commented Mar 31 at 2:11
  • $\begingroup$ Also, do you mean a shock wave refracts around higher/lower density air some distance away, or another shock wave, or light is refracted by a shock wave? It's not even clear what you are asking. What would the density profile of this shock wave look like, roughly? and How is the camera positioned for these plane-to-plane Schlieren images of shock waves? and What do the components of a shockwave's visual artefacts represent? $\endgroup$
    – uhoh
    Commented Mar 31 at 2:13
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    $\begingroup$ @uhoh I am mainly taking about the effect where shockwaves can refract off of each other. $\endgroup$
    – Wyatt
    Commented Mar 31 at 2:15
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    $\begingroup$ @uhoh I see. I was going to add something like a picture of it, but I personally couldn't find anything that looked acceptable. After a bit of research, I found where I initially got this idea from, adding it now! $\endgroup$
    – Wyatt
    Commented Mar 31 at 2:43
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    $\begingroup$ @uhoh, perhaps there are significant differences that would make it a poor comparison. Just asking in case observing waves interacting may shift perspective enough to create insight. $\endgroup$
    – Michael Hall
    Commented Apr 1 at 17:46

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The quote you cite does not say refraction. It says rarefaction.

Refraction (of light) is when light bends because it transitions from one material to another -- say air to water.

I do not think people talk about shocks refracting -- if you have an example, please post it and ask specific questions about it.

I found this image of a refracted shock. Here, an explosion occurred at the 'Source' above the ground. The initial shock spreads out spherically. When the shock hits the ground, there is both a reflection from the surface of the earth -- and also a transmission of the shock into the earth.

enter image description here

The shock will travel differently through earth than through air -- at a minimum, the speed of sound in a solid (or liquid) is much different than the speed of sound in a gas.

While this is a fascinating problem, I don't think it is what you're actually interested in.

Rarefaction is a process of becoming more rare -- spreading out -- weakening. Shocks can interact in a way that they weaken one another.

Instead of using the words Rarefaction, I believe I usually use the term 'Expansion Fan'

Here is an image of two shocks interacting that cause an expansion fan -- I think this could also be called a rarefaction zone.

enter image description here

As some of the criticism alludes, this question shows that you've put in very little effort. You're asking the answerer (us) to do more effort than you did. That is generally bad form. It is much better for you to come to us with small specific details after you've conducted extensive study.

Also, I saw that you posted this in Physics Stack Exchange. I believe it is bad form to cross post identical posts at the same time.

Unfortunately, there is no 'Aerospace Engineering' stack exchange. For the most part, Aviation SE is willing to tolerate us asking and answering Aerospace Engineering questions here, but we do occasionally get asked 'Is this Aviation'?

That said, Physics SE is not the right place either.

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    $\begingroup$ I see. So I understand that part, but if you look at the right diagram on this page from NASA, the shocks seem to bend as they cross. Is this considered rarefacting? - my usual way of asking questions is I will do my research (maybe not as much as I should), and then if I have specific questions I’ll come here and ask without providing evidence that I have done such research. I try to keep the question short and simple, but maybe I should $\endgroup$
    – Wyatt
    Commented Mar 31 at 5:22
  • $\begingroup$ Start providing the research. $\endgroup$
    – Wyatt
    Commented Mar 31 at 5:23
  • $\begingroup$ I rarely ask the same question twice, but sometimes I feel P.SE is more suited for some questions more related to physics (not that this one even is this time). Shouldn’t have done it, but at the time I thought it was a good idea. $\endgroup$
    – Wyatt
    Commented Mar 31 at 5:28
  • $\begingroup$ One last thing: if shocks going into the ground refract, why wouldn’t they do that going through other shocks? The formula for sound speed is $c=\sqrt{\frac Kρ}$. If density is higher, (in shockwave) wouldn’t that change the speed of sound, making the shock refract? $\endgroup$
    – Wyatt
    Commented Mar 31 at 15:41
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    $\begingroup$ The figure at the right in your image from NASA. Those shocks bending is not called rarefacting or refracting. That is just bending a shock. These two examples have great descriptions in the text on that NASA page. That kind of thinking is exactly how you should approach problems like this. $\endgroup$
    – Rob McDonald
    Commented Mar 31 at 22:35

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