6,927 reputation
1424
bio website en.wikipedia.org/wiki/…
location United States
age 70
visits member for 2 years, 10 months
seen 1 hour ago

BS Mechanical Engr.
PhD CS(AI)
CS Prof (4yr)
Numerous consulting jobs.
15 yr at http://www.pharsight.com
Published book on CS & several articles
4 kids, 2 grand
Pilot(student)

P.S. The picture is a Beta-prime distribution. It shows the program speedup factors you can get if you see a problem twice in 2, 3, 4, and 5 samples.


1h
comment Is a falling, perfect sheet of fluid possible to create?
This would be a good experiment to try in micro-gravity. I think the only significant force would be surface tension, which you could minimize by a) making it large, or b) making it soapy :), or c) putting a solid ring around it.
1d
answered Stopping angular momentum to obtain a particular angle
Jul
18
comment Another layman blackhole question, pulling one end of a string out from behind the event horizon
You could just have a stationary scaffold around the entire black hole, and stand on that.
Jul
17
comment Add weight in front or behind the moving wheel?
@user55493: I see kids do it all the time. They go up-hill on their skateboards in a series of S-turns. Each curve of the S-turn, they are pushing sideways. It doesn't matter how many wheels they do it on, or whether their weight is forward or back. What matters is the sideways push.
Jul
16
revised Add weight in front or behind the moving wheel?
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Jul
16
answered Add weight in front or behind the moving wheel?
Jul
16
revised Add weight in front or behind the moving wheel?
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Jul
14
comment Does the Higgs boson give mass to ALL other particles?
Is it possible that the mass of nucleons is mostly the energy (over $c^2$) of the binding of their components, and not really anything to do with the Higgs field?
Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS: It's a great question you asked. In my pilot training, I was taught to be very aware of "wake turbulence" - those invisible vortices coming off heavy-plane wingtips.
Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS: I just googled "vortex merging" and a ton of high-quality stuff turned up!
Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS: Now I'm the one who's skeptical :) Any vortex has to have a central region of low pressure, so that the pressure gradient provides the radial acceleration keeping it circular, so when the vortices come close together, the pressure gradients have to superimpose, affecting the paths of particles. But the trouble is, if that were the only effect, then counterrotating vortices would also merge. Hmmm...
Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS: Well, as I said, when they come close together there will be counter-rotation between them. This will divert flow from each vortex to the other. If you're after a mathematical description of this process, maybe you should research it or better yet, construct it. For the other case, counter-rotating vortices, they don't merge because the physics are obvious, as Floris pointed out.
Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS. Then check Floris' answer. It's a simple matter of conservation of vorticity (i.e. angular momentum), and kinetic energy.
Jul
14
revised Why do co-rotating vortices coalesce, but not counter-rotating ones?
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Jul
14
revised Why do co-rotating vortices coalesce, but not counter-rotating ones?
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Jul
14
comment Why do co-rotating vortices coalesce, but not counter-rotating ones?
@BrysonS. Forget subsumption. They simply merge, because each little parcel of air follows a path.
Jul
14
revised Why do co-rotating vortices coalesce, but not counter-rotating ones?
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Jul
13
answered Why do co-rotating vortices coalesce, but not counter-rotating ones?
Jul
11
answered What is the mechanism of vortex angular acceleration?
Jul
11
comment Computing the force generated by a sail on a boat
@T.Kiley: I'm afraid you need to know how the sail functions as an airfoil - namely what is its chord, its angle of attack, and its coefficients of lift and drag as a function of those.