Airflight Vortex

Guang-Xing Li

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Vortex

• Curl of Velocity

• Angular momentum carried by the flow

Observations Travel from Beijing to Hailaer, summer, 2010 Boeing 737, Cloudy day

Wing Structure

Zooming in--Launching

One Possible Explaination

Vortex Due to Wing Shape

One Possible Explaination

Vortex Due to Wing Shape

One Possible Explaination

Vortex Due to Wing Shape

Fluid Motion

Rotation Axes

Aileron

Wing Flap

Change of Pressure Pressure change due to vortex

Phase transition(water vapor condensation) due to Pressure deviation

Vapor Phase Transition

Vapor Phase Transition

For 0.004 atm, we need relatively humidity of 0.985 (Reasonable)

Summary

• Wing configuration can generate vortex

• The pressure inside the vortex will drop, due to rotation

• Pressure difference induced by vortex rotation is enough to drive water condensation

Wing-Tip Vortex

Wing-tip Vortex

Vortex Evolution

G. Huppertx’s ppt

• Vortex can be generated during the flight

• Sometimes visible, due to water vapor condensation

• Sometimes invisible, can be observed through dynamical effects

– Dangerous for small aircrafts

Vortex Diffusion

G. Huppertx’s ppt

Summary

• Wing configuration can generate vortex

• The pressure inside the vortex will drop, due to rotation

• Pressure difference induced by vortex rotation is enough to drive water condensation

• Other ways to generate vortex during air flight?

How they fade: diffusion?

• Diffusion equation.

• Difficulties:

– Re ~ 10^3, Turbulent Diffusion

– Vortex-Turbulence Interaction, Vortex-Vortex inter.

• Lasts for a few minutes

• Complicated Interaction in later stages