VPM Overview

[Robert Helling]

On 11.03.2014, at 15:17, Robert Helling <helling at atdotde.de> wrote:

> I have more to say about the later parts of that web page (from “applying VPM to diving”). But have to rush now.


Here is a continuation:

Regardingt the derivation of eqs. (19)/(20): I have tried very hard but only got something somewhat close but distinctly different. I have the strong suspicion that there is typo in (18a), the cube just looks so wrong (not only unit wise). With a slightly modified (18) I believe i could obtain (19).

You say, you confirmed (19). Could you show me how? Doesn’t need to be typed, could be handwritten an scanned as well.

I haven’t gotten around completely understanding the derivation the quadratic equation that leads to (40). But maybe I once again I haven’t tried hard enough.

I also have to admit all the talking around the bubble regeneration with tau_R sounds fishy to me: given it the half-time is 20160min which happens to be two weeks. This is much longer than any timescale encountered in recreational (and recreation tech) diving. Thus it could equally well taken to be infinite. In particular things like exp(-t/tau_r) where t is any diving relevant time, I am sure can be safely approximated by 1. Such a long timescale should not influence anything in diving. Making this simplification makes a lot of things shorter.

Regarding “more intert gases”: what is said around (42) sounds to me to speak against the theory of different bubbles for different gases.

I still have some reading of the python code to do. These ultra long variable names don’t help readability.

So much for now.

Best
Robert
 
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Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
                      Phone: +49 89 2180-4523  Theresienstr. 39, rm. B339
                      http://www.atdotde.de

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