The physics flows come faster than furious photons in this one. Features none other than Weird Al as Isaac Newton! And a special cameo from Jurassic 5’s Chali 2na as none other than Neil deGrasse Tyson.
(Hint: We did, all of us, because this is awesome)
Neil deGrasse Tyson won.
Last night I walked across the stage as a student for the last time, receiving my PhD in aerospace engineering and getting hooded by my advisor in a tradition with roots back to medieval scholars. Even more so than the defense, it marked an official end to my PhD. None of that is really fluid dynamical, but I wanted to use the opportunity to thank each and every one of you who read and support FYFD. This blog began on a whim while I was a graduate student waiting for an opportunity to do the experiments I needed. I never could have predicted at the time the impact it would have on my life. FYFD became a part of my daily life, and thanks to you, readers, it became a source of inspiration and motivation for me as I pursued my studies. I have learned so much more about fluid dynamics in writing FYFD and answering your questions than I would ever have on my own. I have had opportunities to travel, to communicate and even meet with people from all corners of the globe who share some of my enthusiasm for the subject. It has been a wonderful experience so far, and I hope for many more ahead. Thank you all for being a part of it! (Photo credit: J. Mai)
So Wednesday’s post was really only a warm up for today’s! This is a fantastic super-super slow mo of a shock wave in our supersonic wind tunnel. Shock waves are very thin regions where the flow properties rapidly change. The oscillation of these shock waves can cause damage or fatigue to aeroplanes or other supersonic vehicles, so the study of this oscillation can be very important.
Here the flow is from left to right and the dark, vertical, black line is the normal shock while the slightly fainter lines are oblique shocks coming from the contraction. The actual video was 8 minutes long but represented only 0.5 seconds in real time. That’s slowed down by almost 1000 times! As with Wednesday’s post the shock waves are visualized using Schlieren photography.
(The movement seems mesmerising, perhaps good for a screensaver?)
What kind of set-up inside the tunnel is generating the pattern of oblique shocks and the unsteady normal shock? It’s almost like this is video from inside a diffuser section of the tunnel if the flow is moving left to right. Or are you still adjusting the geometry to reliably start the supersonic flow in the test section?