you are wasting 40K of tuition for something that you can get from youtube, dear stranger if you think this guy can provide better education. oh i forgot, you need the paper :P
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
Yes, this is correct. I also realized that this video incorrectly states that the air velocity "speeds" up through oblique shocks and that oblique shocks have "little effect on drag". This is incorrect. Oblique shocks create less drag and flow deceleration than normal shocks or bow shocks, but the Mach number always decreases across an oblique shock. For a normal shock the Mach number after the shock must always be subsonic but through an oblique shock, supersonic flow can be maintained, but the Mach number will still decrease.
that is true, the velocity of the air only speeds up at convex corners which creates expansion waves. the complete opposite of oblique shockwaves. expansion waves are often referred to as the antithesis of oblique shock waves.
@@Kebab_with_extra_garlic_mayo The bad part is that he sounded so very sure of himself. Even worse, some people will believe him without checking his figures .
I think you might be thinking of the sweep being used to keep the wing leading edge behind the oblique shock from the nose. He was referring to an oblique shock on the leading edge of the wing I think - but still don’t agree that it accelerates the air!
@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.
Superb conceptual representation of knowledge based Shockwave phenomena, principles and patterns surfacing design decisions focused on applications areas.
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.
@@gerardoespino4382 it dependes on the angle of the shock wave and on the M1, there is no a general way to say " After the oblique shock wave the air is always subsonic"
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!
Have to point out another mistake. Supersonic means faster than the speed of sound, i.e. the speed at which mechanical wave propagates, NOT the speed of air molecules. This is a common misunderstanding
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.
Great video, it has some mistakes like the comment says but if the one watching has some logical thinking he will easily see that it’s a mistake. The biggest one that can misdirect people is the fact that you say the flow will accelerate past oblique shockwaves, this isn’t true. Airflow always decelerates with the encounter of a shockwave!!!
I learned more in this 8 minute than in the 4 lectures with prof
Your professor isn't very good then
bullshit
maybe you should put ypur phone away during lectures
you are wasting 40K of tuition for something that you can get from youtube, dear stranger if you think this guy can provide better education. oh i forgot, you need the paper :P
True brother.
I have Test tomorrow. Pray for me 🙏🏻😂
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
Yes, this is correct. I also realized that this video incorrectly states that the air velocity "speeds" up through oblique shocks and that oblique shocks have "little effect on drag". This is incorrect. Oblique shocks create less drag and flow deceleration than normal shocks or bow shocks, but the Mach number always decreases across an oblique shock. For a normal shock the Mach number after the shock must always be subsonic but through an oblique shock, supersonic flow can be maintained, but the Mach number will still decrease.
that is true, the velocity of the air only speeds up at convex corners which creates expansion waves. the complete opposite of oblique shockwaves. expansion waves are often referred to as the antithesis of oblique shock waves.
Best explanation of Shock Waves I've ever heard or seen. Bravo!
6:50. My understanding is that wing sweep is used to avoid shocks all together, not create oblique shocks instead of normal shocks.
thats true as it increases the percieved chord of the wing, I'm suprised by how many errors this video has
@@Kebab_with_extra_garlic_mayo
The bad part is that he sounded so very sure of himself.
Even worse, some people will believe him without checking his figures .
I think you might be thinking of the sweep being used to keep the wing leading edge behind the oblique shock from the nose. He was referring to an oblique shock on the leading edge of the wing I think - but still don’t agree that it accelerates the air!
@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.
Superb conceptual representation of knowledge based Shockwave phenomena, principles and patterns surfacing design decisions focused on applications areas.
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.
I have to say it… all this talk about waves and your audio for this video is killing my synapses!!!
Sorry you were mistaken about oblique shockwaves. M2T1, P2>P1 and rho2>rho1
I LEARNT MORE OVER HERE THAN MY ACTUAL CLASS THANK YOU!!!!!!!!!!!!!!!!!!!!!!!
everything is wrong here dude
2:30
thanks
always relate what you understood to something you know and you will never forget
@6:34 Shouldn't it be M>1 not M>0 for supersonic and vice versa for subsonic?
ya it should be M>1
5:15 you should revise that statement
I agree, I believe M1>M2. Per my understanding, through an oblique wave, M2 will still be supersonic, but lower than M1. Good video though.
@@gerardoespino4382 it dependes on the angle of the shock wave and on the M1, there is no a general way to say " After the oblique shock wave the air is always subsonic"
Can u explain that part im confused
exactly!
Terrific presentation for understanding shock waves.
many things in this video are wrong
4:46 looks like the notation on theta and beta is reversed
What a superb video.
So helpful
Superb video. Thank you.
This video is absolutely fantastic!
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!
Oblique shocks decelerate the flow. The expansion waves are the oblique waves which increase the mach number instead.
Great video, short and concise explanation!
Best explanation ever thank you.
This is a very simple but amazing way to demonstrate this phenomenon
This viedo is full of big mistakes. M
It's actually 0.3
@@gamersvalley M=0.3 is a boundary of compressible/incompressible flow
The expert in the first part, soundwaves/pressurewaves? Dont go faster than the wing they are simply just pushed out of the way.
Have to point out another mistake. Supersonic means faster than the speed of sound, i.e. the speed at which mechanical wave propagates, NOT the speed of air molecules. This is a common misunderstanding
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.
Why does the bigger fan suck more air and becomes slower in speed?
Fascinating. Thanks for posting. Liked and linked.
Good explanation
this guy still alive?
oblique shockwave decrease the Mach but is still supersonic please correct this video
Very informative video, although there are slight errors, overall the video is very helpful
That F-22 was not supersonic...
427 SuperSnake1
Thank you,
Yes, it was just loud .
Sound edit.
You sir please clear your concepts before teaching...@ 5:16 you mentioned M2>M1 which is incorrect. The shock wave causes flow to decelerate so M2
thumbnail shows this guy was literally shocked
Thank-you, concise and interesting.
Really good video, thanks!
this vdeos should be taken with some grains of salt, lots of simple errors here
Great video, it has some mistakes like the comment says but if the one watching has some logical thinking he will easily see that it’s a mistake. The biggest one that can misdirect people is the fact that you say the flow will accelerate past oblique shockwaves, this isn’t true. Airflow always decelerates with the encounter of a shockwave!!!
Pasted Picture
1:17
Sorry buddy, my religion forbids me from accepting potential flow theory's results of airflow around bluff objects.
Nice footage, but with false information.