From: Ml10@aol.com Sent: Wednesday, July 26, 2000 4:38 AM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Supercavitating Submarines One thing that should be made clear is that this method of underwater propulsion is unsuited for manned vehicles for a number of reasons. The biggest problem with a manned vehicle would be surviving the vehicle stopping. Once the vehicles speed drops below the critical speed (the article states 50m/s but it really depends on the pressure of the surrounding fluid), the bubble collapses and drag increases exponentally. This causes very rapid deceleration (kinda like hitting a brick wall). The next largest problem is the energy required to form the bubble. A /. reader calculated for a 2m wide vehicle, it would require 2.5GW to form the bubble. Another problem would be the manuverablity (or lack there of) of sure a vehicle. Given how the bubble is formed turns would have to be very shallow, otherwise you'll risk collasping the bubble (which brings us back to problem #1). Given the speed and the turn radius, it will take tens of kilometers to make a simple 60 degree turn. Mike Z In a message dated Wed, 26 Jul 2000 4:38:15 AM Eastern Daylight Time, Myles Corcoran writes: << Ronald Johnson wrote: > > Here is an article discussing research into supercavitating torpedos, bullets, > and eventually submarines, that may break supersonic speeds underwater. > > http://www.newscientist.com/features/features_224813.html Apparently the US Navy have already experimented with unpowered supercavitating bullets that made about 5400 km/h in water using this method. (according that New Scientist article.) Note that guidance for a body immersed in a shell of water vapour (from cavitation) is difficult, as any control surfaces only serve to slow the whole thing down. I was disappointed, though not surprised, that no mention was made in the article of the environmental effects of the sound of supercavitating bodies in water. Bringing it back to Poseidon for a moment I suspect that the Aborigines would respond in some fashion to any one making that much noise in the water. Or maybe supercavitating bodies just happen to mimic the love call of the Greater White? Myles -- Myles Corcoran - Alcatel Ireland Ltd., Bandon, Cork, Ireland 023 20469 (w) - 023 20481 (fax) - 021 503904(h) myles.corcoran@ck.cit.alcatel.fr - mylesc2@eircom.net *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Myles Corcoran [myles@irls3101.ck.cit.alcatel.fr] Sent: Wednesday, July 26, 2000 3:33 AM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Supercavitating Submarines Ronald Johnson wrote: > > Here is an article discussing research into supercavitating torpedos, bullets, > and eventually submarines, that may break supersonic speeds underwater. > > http://www.newscientist.com/features/features_224813.html Apparently the US Navy have already experimented with unpowered supercavitating bullets that made about 5400 km/h in water using this method. (according that New Scientist article.) Note that guidance for a body immersed in a shell of water vapour (from cavitation) is difficult, as any control surfaces only serve to slow the whole thing down. I was disappointed, though not surprised, that no mention was made in the article of the environmental effects of the sound of supercavitating bodies in water. Bringing it back to Poseidon for a moment I suspect that the Aborigines would respond in some fashion to any one making that much noise in the water. Or maybe supercavitating bodies just happen to mimic the love call of the Greater White? Myles -- Myles Corcoran - Alcatel Ireland Ltd., Bandon, Cork, Ireland 023 20469 (w) - 023 20481 (fax) - 021 503904(h) myles.corcoran@ck.cit.alcatel.fr - mylesc2@eircom.net *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Christopher Gribbon [c.gribbon@dundee.ac.uk] Sent: Wednesday, July 26, 2000 6:18 AM To: blue_planet@lists.imagiconline.com Subject: [BLUE PLANET] - Bouncing messages By the way - was I the only one to get about 60 zillion copies of a couple of messages last night? It was two copies of messages from Jeb Boyt. I came in this morning and crashed three computers trying to open my email account. Hopefully the problem is an easily preventable one? Christopher Gribbon Vision Research Laboratories Medical Sciences Institute University of Dundee Dundee DD1 5EH UK (01382) 344 229 ____________________________________________________________________ "A scientist is meant to be disinterested, pure; his ambition merely to descry the cement of the universe. He isn't meant to use it to start laying his own patio!" - WILL SELF, The Quantity Theory of Insanity *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Gareth Hanrahan [hanrahag@iol.ie] Sent: Wednesday, July 26, 2000 5:23 AM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Bouncing messages On Wed, 26 Jul 2000, Christopher Gribbon wrote: > By the way - was I the only one to get about 60 zillion copies of a couple of messages last > night? It was two copies of messages from Jeb Boyt. Stop exaggerating. It was only 200 messages or so. :-) But yeah, I think everyone got swamped. > Christopher Gribbon Gar *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Ville.Halonen@minedu.fi Sent: Wednesday, July 26, 2000 5:26 AM To: blue_planet@lists.imagiconline.com Subject: VS: [BLUE PLANET] - Bouncing messages Christopher Gribbon wrote: >By the way - was I the only one to get about 60 zillion copies of a couple of >messages last night? I was intending to ask the same question. Of course, it was nice to see for once that I had about 200 messages in my inbox. *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Poh tun Kai [pohtk@hitech.com.my] Sent: Wednesday, July 26, 2000 5:45 AM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Bouncing messages > By the way - was I the only one to get about 60 zillion copies of a couple of messages last > night? It was two copies of messages from Jeb Boyt. > I came in this morning and crashed three computers trying to open my email account. > Hopefully the problem is an easily preventable one? Yeah, that was annoying, and that's all I'm going to say about it, lest this be perceived as wasting bandwidth. All I want now is for someone to explain what happened, and how it can be prevented from happening again. Kai Poh Malaysian Lagomorph *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Heivilin, Jim [banzai@missouri.edu] Sent: Wednesday, July 26, 2000 8:55 AM To: 'blue_planet@lists.imagiconline.com' Subject: RE: [BLUE PLANET] - Bouncing messages > -----Original Message----- > From: Poh tun Kai [mailto:pohtk@hitech.com.my] > Subject: Re: [BLUE PLANET] - Bouncing messages > > All I want now is for someone to explain what happened, and > how it can be prevented from happening again. > Were I familiar with the email server and client Jeb were using I might venture an opinion. Being uninformed in those areas all I can do is speculate. I doubt it was something on our (the list server - majordomo) end (Rob usually keeps us - list owners - informed of those type of problems). Jeb, if you're listening, I'd say check your system for viruses and ask your email server administrator to look into it. Thanks and Sorry, everyone, for the inconvenience, Jim Jim Heivilin, Webmaster Biohazard Games http://www.biohazardgames.com *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Jeb Boyt [jeboyt@hotmail.com] Sent: Wednesday, July 26, 2000 1:13 PM To: blue_planet@lists.imagiconline.com Subject: RE: [BLUE PLANET] - Oh no! What have I done? (Was: Bouncing messages) Sorry about that. I knew that there was a problem when the message took forever to send and then there were 160 new messages in my inbox, with more there this morning. For the record, I was using a Mac running AOL 4.0 and sending through Hotmail (convoluted I know). On my end, I got a failure message from Hotmail saying that it had been unable to deliver the message. Hotmail was apparently resending the message because it thought that the message had not been received. I also received a Java error message when entering the composition page that may have been related. I have not had this problem sending to other addresses. I'm using a different system and ISP for this message, so hopefully there will be no problems. I'll scan for viruses and for the time-being not transmit messages to the listserv from my Mac. Thank you for your forbearance. Jeb PS - My review of Blue Planet v1.0 should be up on RPG.net this week or next. ----Original Message Follows---- From: "Heivilin, Jim" Reply-To: blue_planet@lists.imagiconline.com To: "'blue_planet@lists.imagiconline.com'" Subject: RE: [BLUE PLANET] - Bouncing messages Date: Wed, 26 Jul 2000 08:55:28 -0500 > -----Original Message----- > From: Poh tun Kai [mailto:pohtk@hitech.com.my] > Subject: Re: [BLUE PLANET] - Bouncing messages > > All I want now is for someone to explain what happened, and > how it can be prevented from happening again. > Were I familiar with the email server and client Jeb were using I might venture an opinion. Being uninformed in those areas all I can do is speculate. I doubt it was something on our (the list server - majordomo) end (Rob usually keeps us - list owners - informed of those type of problems). Jeb, if you're listening, I'd say check your system for viruses and ask your email server administrator to look into it. Thanks and Sorry, everyone, for the inconvenience, Jim Jim Heivilin, Webmaster Biohazard Games http://www.biohazardgames.com ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Chad Chirhart [seahawk@visi.com] Sent: Wednesday, July 26, 2000 1:30 PM To: blue_planet@lists.imagiconline.com Subject: Re: VS: [BLUE PLANET] - Bouncing messages On Wed, 26 Jul 2000 Ville.Halonen@minedu.fi wrote: > Christopher Gribbon wrote: > >By the way - was I the only one to get about 60 zillion copies of a couple > of > >messages last night? > > I was intending to ask the same question. Of course, it was nice to see for > once that I had about 200 messages in my inbox. I just though it was a really heated debate going on lastnight, well until I glanced at the sender. That article on supercavitation was really cool. So anything like that going to show up in BP2? Or should we start writing cool articles for Undercurrents. Speaking of fluid dynamics and such, anybody know of any good books on submarine design. I had plans on picking up a book on elements of ocean engineering. Chad Chirhart seahawk@visi.com *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Chad Chirhart [seahawk@visi.com] Sent: Wednesday, July 26, 2000 1:48 PM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Supercavitating Submarines I would be under the assumption that any vehicle trying to reach supercavitating speeds would vent gas to artifically create the field at first. The article made mention of the russion torpedo using this technique to keep it going. This technique could also be applied to slowing down and stopping so it wouldn't be quite like hitting a brick wall. Although how much time this would add to a vehicle trying to stop I couldn't say. The article did say something about research into turning an object but that it couldn't be discussed. Couldn't something similar to air brakes on airplanes be used? I would think the closer the brake pad got to the supercavitating barrier the more the resistance would increase and the quicker the craft would turn. The one thing that popped into my mind while reading is how would a craft using supercavitation be affected if decending? There would be greater pressure on a supercavitating bubble the further one decends and it was mention that the reason this whole effect occurs is because the pressure around the object decreases to a certain level to allow formation. Chad Chirhart seahawk@visi.com On Wed, 26 Jul 2000 Ml10@aol.com wrote: > > One thing that should be made clear is that this method of underwater propulsion is unsuited for manned vehicles for a number of reasons. > > The biggest problem with a manned vehicle would be surviving the vehicle stopping. Once the vehicles speed drops below the critical speed (the article states 50m/s but it really depends on the pressure of the surrounding fluid), the bubble collapses and drag increases exponentally. This causes very rapid deceleration (kinda like hitting a brick wall). > > The next largest problem is the energy required to form the bubble. A /. reader calculated for a 2m wide vehicle, it would require 2.5GW to form the bubble. > > Another problem would be the manuverablity (or lack there of) of sure a vehicle. Given how the bubble is formed turns would have to be very shallow, otherwise you'll risk collasping the bubble (which brings us back to problem #1). Given the speed and the turn radius, it will take tens of kilometers to make a simple 60 degree turn. > > > Mike Z > > In a message dated Wed, 26 Jul 2000 4:38:15 AM Eastern Daylight Time, Myles Corcoran writes: > > << Ronald Johnson wrote: > > > > Here is an article discussing research into supercavitating torpedos, bullets, > > and eventually submarines, that may break supersonic speeds underwater. > > > > http://www.newscientist.com/features/features_224813.html > > Apparently the US Navy have already experimented with > unpowered supercavitating bullets that made about 5400 km/h > in water using this method. (according that New Scientist > article.) Note that guidance for a body immersed in a shell > of water vapour (from cavitation) is difficult, as any > control surfaces only serve to slow the whole thing down. > I was disappointed, though not surprised, that no > mention was made in the article of the environmental effects > of the sound of supercavitating bodies in water. Bringing it > back to Poseidon for a moment I suspect that the Aborigines > would respond in some fashion to any one making that much > noise in the water. Or maybe supercavitating bodies just > happen to mimic the love call of the Greater White? > > Myles > > -- > Myles Corcoran - Alcatel Ireland Ltd., Bandon, Cork, Ireland > 023 20469 (w) - 023 20481 (fax) - 021 503904(h) > myles.corcoran@ck.cit.alcatel.fr - mylesc2@eircom.net *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message. From: Atti2dboy@aol.com Sent: Wednesday, July 26, 2000 4:55 PM To: blue_planet@lists.imagiconline.com Subject: Re: [BLUE PLANET] - Re: Robots >From: postmaster@mail.hotmail.com > >To: jeboyt@hotmail.com > >Subject: Delivery Status Notification (Failure) > >Date: Tue, 25 Jul 2000 21:48:02 -0700 It did not fail. I received at least 100 copies of the e-mail. THX-1138, indeed! Rich "The truly hungry man does not question the nature of the food on his plate." *************************************************************************** To unsubscribe from this list send mail to majordomo@lists.imagiconline.com with the line 'unsubscribe blue_planet' as the body of the message.