On Aug 15, 12:28*pm, Bruce wrote:
On Fri, 14 Aug 2009 05:12:05 -0700 (PDT), Andy
wrote:



Really? Can you explain how turbulent air gets hotter without
friction?

You're talking about skin friction between the train and the air. *

Where did I say that? I just mentioned friction.

I'm talking about turbulence. *Two very different things, as I am sure you
will continue to fail to appreciate.

I majored in fluid flow at University.

Really and you are still talking ********, I'm impressed.

There is NO heating directly from the turbulent air. All the heating
which might arise from turbulence comes from fricton. Both between the
moving air and the tunnel walls and between air flows moving at
different speeds. Bulk flow of any fluid doesn't make it hotter; but
the interaction of different moving sections of air gives rise to
friction and it is this the friction that causing the air to get
hotter, not the turbulence itself.

You were the one saying that friction is the minority cause of heating
when, in fact, it is pretty much the only direct cause of heating.
Just to emphasize the point. TURBULENCE causes FRICTION which leads to
HEAT, which part don't you understand?