Aerospace/Aviation/Aerodyanamics

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Expert: - 1/31/2011


Question

smoke trail
Sir,
as u can see in the picture of f-22 raptor that there is a smoke trail over the wings of the plane.I am sure that this smoke is not coming out of the plane's engine because the smoke trail is starting over the top of the rudder and at the edge of the wings.
So can u please tell me the cause of this smoke trail.I have also noticed that this smoke trail generates only when the plane turns or increase/decrease altitude.
Plz help
Thank You
Shatanu

Answer
At the tip of all lifting surfaces (wings, rudder, horizontal stabilizer...) there is a vortex...  in the core (center) of the vortex the pressure is low...  any moisture in the air will condense and form water droplets (fog or a cloud)...  that is what you are seeing...  the atmospheric conditions have to be right for this to happen, but it happens even for large commercial jetliners (off of some of the flap surfaces upon landing for instance)...

Hope this helps,
mj

Mark Janus

Expertise

I can answer questions regarding aerodynamics, fluid flow, and computational simulations.

Experience

turbomachinery flow analysis, computational fluid dynamics

Organizations
Mississippi State University

AIAA

SIAM

Publications
AIAA SIAM

Education/Credentials
Ph.D. in Aerospace Engineering

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