Pegasus Research Consortium

Breaking News => Breaking News => Topic started by: burntheships on October 12, 2011, 09:39:49 am

Title: Prandtl–Glauert Singularities and Vapor Cones and Moisture Trails Oh My!
Post by: burntheships on October 12, 2011, 09:39:49 am


Weather conditions were just right the weekend of
October 9, 2011, creating the opportunity for some fantastic
photography during the Air Show of Fleet Week, held in San Francisco, CA.

I was hoping to get to see this phenomenom first hand,
as I attended the event for a few days. No such luck.
However I did get some great video footage which I will post
soon, and some decent photos.

Fortunately, there are some very skilled
photographers who did get these interesting moments captured!

Mix together some high humidity and fast aircraft and you
get a a few shock collars (sometimes known as Prandtl-Glauert
singularities, shock eggs or vapor cones).
http://en.wikipedia.org/wiki/Prandtl%e2%80%93Glauert_singularity

Photo Montage from Fleet Week, San Fransico, CA October 2011

(http://files.abovetopsecret.com/files/img/ya4e95bed5.jpg)


These are pictures of planes traveling at transonic speed. Around the plane air is compressed into higher- and lower-pressure regions which cause instability in the flow. This builds up into a shockwave, and as the plane passes through it causes moisture to precipitate out of the air  - the shockwave of the plane creates high-pressure region in which moisture condenses producing the "shock collar". 



http://sfist.com/2011/10/10/photos_fleet_week_air_show_2011.php#photo-1  (http://sfist.com/2011/10/10/photos_fleet_week_air_show_2011.php#photo-1)

(http://files.abovetopsecret.com/files/img/pb4e95c658.jpg)

http://www.flickr.com/photos/agrinberg/6225347132/sizes/o/in/photostream/ (http://www.flickr.com/photos/agrinberg/6225347132/sizes/o/in/photostream/)
Title: Re: Prandtl–Glauert Singularities and Vapor Cones and Moisture Trails Oh My!
Post by: burntheships on October 25, 2011, 11:34:15 pm
Caught on video, Amazing!

[youtube]dpo72HkrBkw[/youtube]

http://www.youtube.com/watch?v=dpo72HkrBkw
Title: Re: Prandtl–Glauert Singularities and Vapor Cones and Moisture Trails Oh My!
Post by: Somamech on October 26, 2011, 12:01:44 am
Thats pretty awesome BTS.  Looks like the jet is coming through a stargate :D
Title: Re: Prandtl–Glauert Singularities and Vapor Cones and Moisture Trails Oh My!
Post by: burntheships on October 26, 2011, 07:26:55 pm
Thats a great word picture, a Stargate!
Yes, it looks likes its breaking in from another dimension!