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    Missile Defense

Russian military leaders have expressed concern about US plans for a national missile defense system. Will defense technology be limited by possibilities for a strategic imbalance? Is this just SDI all over again?

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rshowalter - 09:30am Mar 19, 2001 EST (#1167 of 1174) Delete Message
Robert Showalter

While I'm typing, I'd like to say that Steve was much interested in peacemaking. The account above is correct, but also a smoothing over of phyologically and emotionally significant detail. Discussion of one of the people involved, who died before Steve, was enough to make Steve wince with rage, right to the very end of his life. I liked that particular person very much, and had personal reasons to.

rshowalter - 09:42am Mar 19, 2001 EST (#1168 of 1174) Delete Message
Robert Showalter

Had I been a little luckier, he would have been my father in law.

rshowalter - 09:54am Mar 19, 2001 EST (#1169 of 1174) Delete Message
Robert Showalter

Correction, end of 1166:

"Indeed John Laufer who had initially been one of the most skeptical individuals about the visual evidence was kind enough, and of sufficient stature, that he wrote me saying that he had been very skeptical initially, but the results cited above had convinced him that what the Stanford group had said about the role of the ejections from the sublayer was at least largely correct."

. . . . . "partially" - which I typed before, was too weak.

rshowalter - 10:21am Mar 19, 2001 EST (#1170 of 1174) Delete Message
Robert Showalter

6. The Era of CFD (computational fluid dynamics) - - - 1986 - ?

“The era of CFD in structure studies began when computers became big enough and fast enough so that direct solutions of the Navier-Stokes equations (DNS, for “direct numerical solutions”) could be performed for at least some turbulent flows. …

Steve Kline’s student S.K Robinson, now an astronaut, made great progress in using CFD. Under Kline’s direct supervision, as part of his Ph.D. thesis, Robinson produced calculations associated with stunning pictures of eddies that look like experimental eddies, for a boundary layer. (Robinson has said that Steve was mercilessly demanding during this period. I was working with Steve also at this time, though not as his student, and I believe him.)

“Robinson used the data from the DNS solution for the plate by Spalart to sudy the structure of the boundary layer. He showed the wall layers do contain counter-rotating vortices oriented and tilted downstream” --- and much other breakthrough detail. “For further detail, see Robinson (1991) and its continuations in a paper by Kline and Portela in this volume.”

“While the shift from the Era of Statistics to the Structural Era involved a paradigm shift in much the way Kuhn suggests, the other two shifts in era did not. The reasons are different. The shift to the statistical era was a movement into uncharted territory where there had been no data and no theory. Hence there were no previous workers to resist the change. The shift to the CFD era did not involve a paradigm shift in the view of turbulence. It involved rather a large increase in the power available for computation.


almarst-2001 - 10:27am Mar 19, 2001 EST (#1171 of 1174)

rshowalter 3/19/01 9:19am

"“When two (or more) groups of scholars create conflicting solutions for a single problem, then it is likely that each group of scholars has some of the truth, but not all of it.”

Isn't it always a case? Do you believe it is possible to have ALL of the truth?

I am not sure how relevant the philosophy of science is to this forum but it is definetly a very exciting topic.

In my view, the science is an attempt to create an all encompassing model based on a limited number of observations taken with the limited precision using defined methodology, deemed to be constant and true. The model assumed to be true if it can predict the pattern of those observations during some (limited) validation period using the some deemed to be valid observation methodology.

As one can see, there are a too large of the number of assumptions in any scientific proposition to ever claim to be absolute true. All we can talk about is some degree of a relative truth.

Moreover, one of the main assumption is the stability of the model on a time dimension. In other words, we assume that our observations today using the same methodology would give us the same result at any point in time in the past or the future. Phylosophically, I am skeptical we can make such an assumption. In doing so, we deny the ability to develop and change to the non-organic "lifeless" matter. Such an assimetrical view does not look phylosophically correct. What if all the matter evolves, adupts and changes over time on all material levels from sub-atomic particles to the galaxies to the universe?

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