raoulsttexas
Contributor
First off, pardon my ignorance on the technicalities of the below scenario. I'm not a physics guy, nor even an engineer.
I was watching a documentary on the evolution of submarines. They mentioned that the props used to cause a huge problem in that they would create bubbles, and therefore sound, and be easier to detect. Evidently, this is called "cavitation". Modern subs have a proprietary blade which reduces cavitation.
So, as I understand it, caviation is caused when the water on the "backside" of a blade creates a low pressure point and the water boils due to the decrease in pressure. O2 is extracted and produces a bubble.
I'm sure there are man MANY details in the above that I am not mentioning nor aware of, but assuming I'm in the ballpark of the above being correct then how about this scenario:
Cave diver is caught in an OOA situation and finds a cavity that is large enough for him/her to keep their head out of the water and is filled with air (big assumption...i know). I'm picturing something around 2'x2'x2'.
The question is, how much oxygen could be generated by waving one's hand, fin, or any other object on a normal scuba rig, and would that be enough to sustain life?
I'm guessing that enough air could be generated to prolong life, but only minimally. I've seen my hand make those bubbles when I wave it quickly in water, but they're small bubbles. The documentary mentioned that the average sailor on a sub needs 400cf of air per day to survive. That seems ridiculously low to me. They MIGHT have said 400cf of O2, and that would make more sense.
Either way, any of you physics gurus want to chime in on this one?
I was watching a documentary on the evolution of submarines. They mentioned that the props used to cause a huge problem in that they would create bubbles, and therefore sound, and be easier to detect. Evidently, this is called "cavitation". Modern subs have a proprietary blade which reduces cavitation.
So, as I understand it, caviation is caused when the water on the "backside" of a blade creates a low pressure point and the water boils due to the decrease in pressure. O2 is extracted and produces a bubble.
I'm sure there are man MANY details in the above that I am not mentioning nor aware of, but assuming I'm in the ballpark of the above being correct then how about this scenario:
Cave diver is caught in an OOA situation and finds a cavity that is large enough for him/her to keep their head out of the water and is filled with air (big assumption...i know). I'm picturing something around 2'x2'x2'.
The question is, how much oxygen could be generated by waving one's hand, fin, or any other object on a normal scuba rig, and would that be enough to sustain life?
I'm guessing that enough air could be generated to prolong life, but only minimally. I've seen my hand make those bubbles when I wave it quickly in water, but they're small bubbles. The documentary mentioned that the average sailor on a sub needs 400cf of air per day to survive. That seems ridiculously low to me. They MIGHT have said 400cf of O2, and that would make more sense.
Either way, any of you physics gurus want to chime in on this one?