Re: Coyote Wake Turbulence

From: Bob Prevett (prevett@shreddr.engr.sgi.com-DeleteThis)
Date: Sat Jul 12 1997 - 11:02:30 PDT

Next message: David R. Fielder: "Berkeley Yesterday"
Previous message: Bob Galvan: "Re: Tiki's Death"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Mail actions: [ respond to this message ] [ mail a new topic ]

From: "Bob Prevett" <prevett@shreddr.engr.sgi.com-DeleteThis>
Message-Id: <9707121102.ZM13369@shreddr.engr.sgi.com-DeleteThis>
Date: Sat, 12 Jul 1997 11:02:30 -0700
In-Reply-To: JRG3%EngSta%GS@bangate.pge.com-DeleteThis "Coyote Wake Turbulence" (Jul 11,  5:13pm)
References: <vines.uN87+ndglnB@go50.comp.pge.com-DeleteThis>
To: wind_talk@opus.hpl.hp.com-DeleteThis
Subject: Re: Coyote Wake Turbulence
Content-Type: text/plain; charset=us-ascii

On Jul 11, 5:13pm, JRG3%EngSta%GS@bangate.pge.com-DeleteThis wrote:
> Subject: Coyote Wake Turbulence
> I became a believer in small waterspouts / tornadoes generated by heavy
> aircraft on final approach into SFO, after seeing them myself within 30'.
> (Wasn't previously sure whether to believe others when they spoke of this...)
>
> My understanding is that heavy aircraft wake turbulence is generally
> believed to consist of horizontal axis rotation, not the vertical axis we see
on
> the water while sailing.
>
> Any of you ever develop theories or research this? Heavy aircraft captains I
> know are interested in our observations or knowledge, and concede that wake
> turbulence is poorly understood by NASA, pilots, et al.

Here's some wind_talk email from Spring '95 on Coyote whirlwind observations:

Date: Mon, 27 Mar 1995 11:24:11 -0800
From: "Bob Prevett" <prevett>
To: Multiple recipients of list <wind_talk@opus.hpl.hp.com-DeleteThis>
Subject: mini-tornados at Coyote Pt...

This saturday at around 5pm I was cruising along on a starboard reach about
halfway in from the orange cone marker at Coyote when out of the corner of my
eye I see a bunch of spray kick up. Two little whirlwinds, each about 30 feet
tall and 10 feet wide were spinning around, were sucking up spray from the
waters' surface. They were moving about 10mph downwind on a collision course
with me! My first instinct was to unhook and prepare to get launched, but then
I realized I had enough speed to get by them. So, I rehooked and bore off on
broad reach and went past the little twisters. About 20 seconds later they
fizzled out.

My theory is that the whirlwinds were caused by a large plane that had just
landed about a minute before I saw them. Horizontal turbulence vortices from
the wing may have turned vertical and touched down.

Has anyone else ever experienced this phenomenon at Coyote Pt?

BobP

Date: Mon, 27 Mar 1995 11:45:50 -0800
From: James.Paugh@Eng.Sun.COM-DeleteThis (Jim Paugh)
To: Multiple recipients of list <wind_talk@opus.hpl.hp.com-DeleteThis>
Subject: Re: mini-tornados at Coyote Pt...

> From: "Bob Prevett" <prevett@shredder.esd.sgi.com-DeleteThis>
>
> My theory is that the whirlwinds were caused by a large plane that had just
> landed about a minute before I saw them. Horizontal turbulence vortices from
> the wing may had turned vertical and touched down.

That's exactly what they were, I've seen them a few times, but not while
I was sailing. It would probably not be real fun to go through one though.

What were you sailing on at Coyote? It sounds like it didn't come up till
late on Sat based on the wind_thresh reports. Was it light?

~Jim

Date: Mon, 27 Mar 1995 12:51:07 -0800
From: "Matt O'Yamaguptakov" <matt@hpwsurf.cup.hp.com-DeleteThis>
To: Multiple recipients of list <wind_talk@opus.hpl.hp.com-DeleteThis>
Subject: Re: mini-tornados at Coyote Pt...

> Has anyone else ever experienced this phenomenon at Coyote Pt?

Yes, I have seen several of these at Coyote Pt. Out of curiosity I once
tried to sail through one. It was not a pleasant experience. As I
approached the whirlwind, the wind became very strong and gusty. When I
reached the center of the whirlwind, it picked me and my board up off
the water, backwinded me and then slammed me down into the water. Like
I said, not a pleasant experience. I am a trained, professional
thrill-seeker - don't try this at home :-).

-matt

-- 
Bob Prevett (prevett@engr.sgi.com-DeleteThis)	Silicon Graphics Computer Systems
(415) 933-5315				M/S 43L-998

Next message: David R. Fielder: "Berkeley Yesterday"
Previous message: Bob Galvan: "Re: Tiki's Death"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Mail actions: [ respond to this message ] [ mail a new topic ]

This archive was generated by hypermail 2b29 : Mon Dec 10 2001 - 02:32:13 PST