In the transonic speed regime the overall speed of an airplane is less than Mach 1 but some parts of the flow around the aircraft break the speed of sound. The photo above shows a schlieren photograph of flow over an airfoil at transonic speeds. The nearly vertical lines are shock waves on the upper and lower surfaces of the airfoil. Although the freestream speed in the tunnel is less than Mach 1 upstream of the airfoil, air accelerates over the curved surface of airfoil and locally exceeds the speed of sound. When that supersonic flow cannot be sustained, a shock wave occurs; flow to the right of the shock wave is once again subsonic. It’s also worth noting the bright white turbulent flow along the upper surface of the airfoil after the shock. This is the boundary layer, which can often separate from the wing in transonic flows, causing a marked increase in drag and decrease in lift. Most commercial airliners operate at transonic Mach numbers and their geometry is specifically designed to mitigate some of the challenges of this speed regime. (Image credit: NASA; via D. Baals and W. Corliss)
What a sad era when it is easier to smash an atom than a prejudice.
Ebola has a nasty reputation for damaging the body, especially its blood vessels. But when you look at the nitty-gritty details of what happens after a person is infected, a surprising fact surfaces.
Illustration credit: Lisa Brown for NPR
Sunsets and sunrises seen from the International Space Station.
Science Needs Women:
For Women in Science; the L’Oreal Foundation
I’m sharing this video on any platform I can because when I first found it last week it had something like 1,400 views, but it’s the most beautifully produced and succinctly narrated video addressing some of the most complicated issues facing women in STE(A)M fields I’ve found yet.
I’m sharing this for every time I’m called a “feminazi.”
…for every time I’m told that my concerns aren’t valid, our that our issues are imagined.
…for every time I hear “women just don’t like science,” or worse - “women just aren’t good at science.”
…for every time we’re told that we can have a family or a career, but not both - and for every time we feel like we have to decide between the two.
…and because we need more women mentors in these fields to stand up for issues that are not “women’s issues” - these are people issues that affect our collective society as a whole.
The women in this video are my heroes and they should be your heroes, too.
reality has a limited amount of information, like a Netflix movie when Comcast is not giving you enough bandwidth. So things are a little blurry and jittery