stbtiger87

Yea, if that's real CFD of a transonic tic-tac, its bad real CFD of a transonic tic-tac. There's no business putting the boundaries that close.

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Dudes in this thread have all aced Fluid dynamics and chaos theory.

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The latter was probably called non-linear dynamics

I have one in engineering. The other people I know with Ph.D.'s definitely tend to run on the interesting side personality-wise but are generally well adjusted. I only know of one guy out of the dozens from school that went to academia. The vast majority in my field are working in areas related to defense, aerospace, or technical software.

My career day speech is that you don't do a Ph.D. because you want to make a boatload more money, you do it because you want an interesting career. Opportunity cost of being in school for that long vs making money for six to eight years is real. You do get free tuition and a stipend typically for engineering though.

Email sent

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You're not concerned with those wood 6x6s warping over time with the constant tension?

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You're probably not wrong that they may warp some over the years but they've been loaded up for about a year and half now and haven't budged. When I load up the shade on the posts, the posts barely move. Probably doesn't hurt that they're loaded up along the diagonal of the post.

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Im having a hard time wrapping my head around how those simpson bases are able to secure those 6x6 with no movement. You are far more brave than I attempting that.

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Those things are beefy and can take some shite. You can only see about half of the base above the concrete and each one has twenty something screws in the post. I designed the pier similar to the recommended reinforced concrete installation from Simpson's catalog. My thought was that I might eventually go from a sail shade to a pavilion or pergola and I wanted something wooden that could handle the sail shade torque on it. Either way, a steel post is about as solid as anything you'll get if that's the answer. Just wanted to toss out there that there's a wood solution if you like the look better.

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That's how I was thinking of it, and that's why I don't see much difference between increasing temperature by molecules bumping each other under compression, or friction shearing or "rubbing" each other.

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Yeah I mean at some point its just a bunch of shite bumping into each other and transferring energy. I think the point to make here is: sure, if you zoom in close enough it a change in temperature all looks the same but in most physics problems the most important implications are because of the boundary conditions of the problem.

If this shite interests you, look up how gas dynamic lasers work. Runs the full gamut of temperature decrease due to expansion, non-equilibrium thermodynamics, and stimulated emission. The last one is waiting for an OT style mom joke.

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Isn't it just semantics though? Doesn't compression just create more friction between air molecules, which creates heat?

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Nope not semantics, compression doesn't create more friction between air molecules.

If you're in a diesel piston before the compression stroke, air is sitting in the piston at some temperature and pressure. That pressure is the force resulting from air molecules colliding with each other and the walls of the cylinder. When you compress the piston, the number of molecules stays the same but you reduced the room that they have to live in so they hit the walls of the piston more often and it higher velocities and as a result the pressure is higher.

Temperature is more complicated in terms of what it actually is but its related to the local kinetic energy (translational and rotational) of the molecules. When you compress the piston, because the molecules have less room they're going to collide more often and their velocity RMS goes up. Overall the temperature is going to increase either way because you put work into the air when you compressed it.

This video helps visualize it

So I actually have a similar perspective to OP - went to LSU for undergrad and finished my Ph.D. @ ND a few years ago. Notre Dame attendance has a few things going for it:

1. When the game starts, all on-campus tailgates at ND have to shut down. There's no going back to the Powalski's (or whatever midwest last name) tailgate to eat brats and simultaneously watch the Irish beat down the Lobos AND watch USC lose to BYU on the second TV.

2. There's not too many places to go right near campus to go do something else. Things improved massively during my tenure there but still there's only a handful of places (Brother's, O'Rourkes, the Backer, ?) right at the edge of campus to eat/drink/watch football.

3. Most of the undergrads live on campus so the alternative to leaving the game is to go back to the dorms. Added to this is since most of the students graduate in four years, about 50% can't legally go out and get boozed up.

4. Most of the non-student tickets are people from out of town. I knew a lot of the season ticket holders would come in from at least Chicago, a big part from well beyond there. If you're making the trip, you're watching the game.

Idk, overall its just a different atmosphere. Tailgating is a little stale sometimes - you could only set up tailgates in the parking lots, drinking games on campus are banned, but you really can't beat the scenery and the history. It felt like college football Disney World sometimes. Night games there where pretty tight though and things could get rowdy.

Mach # = velocity/sound speed. The speed of sound is less in the upper atmosphere and the air is pretty rarified so attaining those speeds doesn't cause the same problems as it would at sea level.

Just look at the HiFiRE missle and X-51 programs - air-breathing hypersonic missles in the dense lower atmosphere is still a very active area area of research partially because of the high temperature you get from air friction on the missle surface.

Conveniently located near the gigantic book store on the south part of campus there's the Eck Visitor Center that has a bunch of really cool historic Notre Dame sports stuff but that might be as close as it gets to a museum. Legend's, one of the on campus restaurants, has some jerseys hanging and some memorabilia. Be sure to catch the stadium and touchdown Jesus (Hesburgh Library) too.

You can usually take a tour of the stadium on Friday's and Saturday's but unfortunately it looks like they're not doing it this weekend because there's something going on.