Understanding Shock Waves in Aerospace Applications

David Sherwood
Created 5/3/15

This educational video is a student production of MIT's Experimental Study Group with assistance from the Department of Aeronautics and Astronautics. The purpose is to provide an exciting and interesting introduction to shock waves and their applications in supersonic flight for individuals at the undergraduate level.

With assistance from Professor David Darmofal, I introduce the concepts behind shock wave formation and delve into the difference between the three main types of shocks. Placing this analysis in the context of aircraft design helps students draw conclusions and hopefully sparks their interest about this crucial
topic.

For Additional information visit MIT OCW Aerodynamics:

Special Thanks to Dave Custer, Graham Ramsay, and David Darmofal

[najeebrazeq]

I learned more in this 8 minute than in the 4 lectures with prof

[MrClijun]

5:16 I don't remember the that the velocity downstream (after) the shock increases higher than the upstream (before) the shock, it's actually the opposite. from what I studied is the velocity component parallel to the shock will be the same before and after an oblique shock, but the velocity upstream will make an angle (Beta) with the shock, and downstream will make an angle (Beta - Theta) which causes the component normal to the shock of V2 will be less than its counterpart in V1, which make the magnitude of V2 less than V1

[samspade]

Best explanation of Shock Waves I've ever heard or seen. Bravo!

[ethanloewenthal]

6:50. My understanding is that wing sweep is used to avoid shocks all together, not create oblique shocks instead of normal shocks.

[paolomaldini]

Sorry you were mistaken about oblique shockwaves. M2<M1 but T2>T1, P2>P1 and rho2>rho1

[CharlesVanNoland]

@5:40 I know I'm 7 years late but this diagram of the engine doesn't take into consideration that when it's in flight the cone lifts up straight. It is pointed down as a side-effect of the spring loaded mechanism that causes airflow to retract it to optimize compression on air intake - and when it retracts it straightens out and no longer points downward. The downward slant of a stationary SR-71 engine cone is just a side effect of the retraction mechanism. It's basically just dangling out there when not cruising through the sky.

[womineer]

@6:34 Shouldn't it be M>1 not M>0 for supersonic and vice versa for subsonic?

[vikrantvijit]

Superb conceptual representation of knowledge based Shockwave phenomena, principles and patterns surfacing design decisions focused on applications areas.

[hakeemnaa]

2:30
thanks

always relate what you understood to something you know and you will never forget

[Fickoch]

I have to say it… all this talk about waves and your audio for this video is killing my synapses!!!

[ManualMaestro]

4:46 looks like the notation on theta and beta is reversed

[Thompsonje]

Terrific presentation for understanding shock waves.

[rajveerramesh]

I LEARNT MORE OVER HERE THAN MY ACTUAL CLASS THANK

[johno]

I remember my aero engineering instructor telling us after we had just studied subsonic aerodynamics to forget everything we just learnt as supersonic aerodynamics is completely backwards.

[erinlucassen]

At 6.55; "swept wings such that normal shocks behave like oblique shocks" is quite a glaring mistake. But other than that thank you for a very informative video!

[WorldEagleKW]

Great video, short and concise explanation!

[fulmen]

Oblique shocks decelerate the flow. The expansion waves are the oblique waves which increase the mach number instead.

[andreamarchionni]

This is a very simple but amazing way to demonstrate this phenomenon

[LordBagdanoff]

Why does the bigger fan suck more air and becomes slower in speed?

[ethanloewenthal]

3:50. Almost all of that is a "mach wave" traveling at the speed of sound. Only the area very near the ball is a "shock wave" traveling greater than the speed of sound, i.e. with the ball.