PPRuNe Forums - View Single Post - Wet adiabat and speed of sound in cloud
View Single Post
Old 27th August 2008 | 17:15
  #13 (permalink)  
chornedsnorkack
 
Joined: Aug 2005
Posts: 834
Likes: 0
From: Estonia
With the pressure changes associated with sound waves propagating through the air, the water droplets will not have time to evaporate and condensate to any significant degree with the small pressure variations caused by the sound waves. In other words, (dry) adiabatic compression.
The chord of a wing is just a few metres. The inlets of engines are just a few metres across at most, and less than that in depth. Yet clouds are commonly seen in low-pressure areas above wing and in engine inlets ahead of fan.

A parcel of air moving at hundreds of m/s past an airframe or into an engine spends just a thousandth or a few thousandths of seconds in the low pressure areas. Yet it is enough time for the moisture to condense.

The latent heat of this condensation must be going somewhere.
chornedsnorkack is offline  
Reply