Timeline for Why do shockwaves extend past the body that created them?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 4 at 4:49 | comment | added | Rob McDonald | Yes, not in a major way, but enough that if you work for NASA and you are doing detailed calculations about how a sonic boom from an overhead aircraft will be experienced on the ground -- you care and it matters. | |
| Apr 3 at 23:49 | comment | added | Wyatt | (strength of shock) | |
| Apr 2 at 17:33 | comment | added | Wyatt | I see. So basically weather, temperature, and wind changes will change the flow turning aspects changing strength? | |
| Apr 2 at 15:40 | comment | added | Rob McDonald | Shock propagation to the ground is a complex thing. The shock's strength will change as it goes through different layers of the atmosphere. Temperature changes are most important, but humidity and wind also have an effect. But basically yes, near the aircraft, there are different interactions that change the shock. Once you get to some mid-distance away, the remaining shock structures are parallel and won't interact anymore (because they don't collide). Those tend to extend until they reach the ground. They also spread out to the sides. | |
| Apr 2 at 15:35 | comment | added | Wyatt | Ah okay. So after the expansion fan, does the shock keep its strength until it reaches the ground? | |
| Apr 2 at 15:23 | comment | added | Rob McDonald | There is an expansion fan. And in general, the shock does extend to infinity. That is why the shock around a 50 foot long aircraft will hit the ground as a sonic boom when the aircraft is lying at 50,000 ft altitude. | |
| Apr 2 at 3:35 | comment | added | Wyatt | Late comment on here, but I was thinking, what will stop the shockwave from extending to infinity? (Considering there’s no expansion fan) I tried looking this up and all I got was stuff about car shock absorbers 😂 | |
| Mar 14 at 19:49 | comment | added | Wyatt | Ah I see, I think I get what you're saying. Thanks again! | |
| Mar 14 at 19:00 | comment | added | Rob McDonald | Usually the normal shock on the surface of a transonic wing only has very short extent. This is because the region of supersonic flow is limited to a bubble on the upper surface of the wing. Once you get to the edge of this supersonic bubble, there is no reason to terminate the bubble with a shock. This is in contrast to the supersonic aircraft -- where the supersonic freestream is everywhere. | |
| Mar 14 at 17:37 | comment | added | Wyatt | Extending parallel meaning outwards. Basically the same thing as the original question was asking. I understand that the high pressure is a result of the shock, but does that high pressure, in any circumstances, help the shock extend outwards? I'm mainly referring to the normal shock on the surface of a wing. | |
| Mar 14 at 17:27 | comment | added | Rob McDonald | I really don't understand what you mean by 'extend parallel'. Shocks are not because of the pressure. Shocks happen because of the turning -- the pressure jump is a result of the shock. | |
| Mar 14 at 16:31 | comment | added | Wyatt | Also something I’ve been thinking about: Because shocks aren’t going to expand perpendicular, is it possible for them to extend parallel? They obviously do, but is it possible for them to because of them being high pressure? | |
| Mar 14 at 16:12 | vote | accept | Wyatt | ||
| Mar 14 at 16:11 | comment | added | Wyatt | That actually makes a lot of sense! I never had thought about it that way. Thanks for your answer! | |
| Mar 14 at 5:16 | history | answered | Rob McDonald | CC BY-SA 4.0 |