Air Flow Measurement

[Anthony Tsakiris]

>>The response to a step increase is faster than a step decrease in airflow.

 > Ok, I though about it alot, and finally talked to all of my ME/ESM buddies
and none of us can think of why this happens.  If you have two Pt elements,
one to measure ambient, and you heat the other to some constant delta-t
above ambient and use the energy lost to find mass flow, there is no
physical phenomenon to say this should work asymetrically with a step change
in the airflow. <

The dissipated energy is dissipated via heat transfer.
The heat transfer can be both convective and radiant.
The convective heat transfer component will change 
markedly with changes in flow; the radiant heat 
transfer will not.  This might lead to different
responses for increasing and decreasing flows.

Anthony Tsakiris