Deep bounce dive crushes micro bubbles?

[Cave Diver]

I ran across a "technique" on another forum that I can't recall ever hearing of before.

The idea was that some divers do a "deep" bounce for a few seconds and then ascend to their planned depth for the remainder of their runtime. The premise is that by doing the deep spike, it will crush microbubbles, presumably resulting in cleaner deco.

Has anyone ever heard of (or used) this technique?

 

[Scott L]

Definately outside my expertise but IMO if it makes any sence at all the spike in depth should occur after the period at planned depth just before the ascent to surface. I doubt it will be well received by those in the know..

 

[AzAtty]

I would think that whatever reduction in volume occurred on the spike would be reversed on ascent. However, I'd want to see the math before I'd outright dismiss the technique, since the stability of a microbubble is influenced by several factors. It could be that quickly crushing a microbubble to a certain critical radius allows the microbubble's surface tension to exert a force such that a relatively modest decrease in ambient pressure (i.e. ascending to planned depth) would not allow the microbubble to expand to its previous dimensions.

I'll be the first to admit that bubble mechanics aren't my strong suit, so my speculation may well be completely wrong. I seem to recall Wienke discussing something along the general line of "crushing" bubbles with relatively quick descents. Have you found anything at Rubicon on the practice?

 

[Scott L]

Fairly irelevant to me as 98% of my dives are to the bottom or fairly close...

 

[Cave Diver]

I seem to recall Wienke discussing something along the general line of "crushing" bubbles with relatively quick descents. Have you found anything at Rubicon on the practice?

I remember reading something about this as well and also thought it was from Wienke. I've been scanning through some other threads and reference in between other stuff but haven't run into anything worthwhile yet on the subject.

 

[Cave Diver]

Here are two articles I found that bear some relevance:

Rubicon Research Repository: Item 123456789/5325

Rubicon Research Repository: Item 123456789/5076

 

[Scott L]

Here are two articles I found that bear some relevance:

Rubicon Research Repository: Item 123456789/5325

Rubicon Research Repository: Item 123456789/5076

I have to ask. If agarose gelatin is a better medium for such experiments why was knox gelatin used in the study? No need to answer as I will not lose sleep over it...

 

[Cave Diver]

I have to ask. If agarose gelatin is a better medium for such experiments why was knox gelatin used in the study? No need to answer as I will not lose sleep over it...

As I read it, Knox gelatin was easier to obtain results in, but Agarose was used because it more closely models mammalian tissue. In order for the results to be valid, some "tweaking" of the experiment was needed to cause bubble formation in the Agarose gel.

 

[Scott L]

As I read it, Knox gelatin was easier to obtain results in, but Agarose was used because it more closely models mammalian tissue. In order for the results to be valid, some "tweaking" of the experiment was needed to cause bubble formation in the Agarose gel.

Thanks! Read too quickly during the first go-round. Feel free to ignor any posts I make after 11:00pm on weekends.

 

[AzAtty]

I remember reading something about this as well and also thought it was from Wienke. I've been scanning through some other threads and reference in between other stuff but haven't run into anything worthwhile yet on the subject.

Now that I think about it, I believe it was in Basic Decompression Theory and Application among the sections relating to bubble models. I remember there's a pretty decent slug of math in that section, and I had to re-learn mathematics I haven't dealt with in 15 years to read it. I'll dig out my copy and see what I find.