Jeff Spitzer wrote:

Vance and Emily Jaqua wrote:

thrust remains mass flow times the

increase in velocity. The exit can also be equated
to horsepower (usually lots of it ) by using mass
flow times velocity squared divided by 2 times
the 550 ft lbs a sec that is one of Watt's tiny
English ponies - Vance

 Thrust is actually mass flow times change in
velocity PLUS integrated pressures around the control volume under
consideration.  It's not a trivial fact.  If you select the control volume
well beyond the inlet and outlet you can ignore the pressures but you must
know the actual cross sections of the streamlines that pass through the
duct at the far field conditions.  Not easy.  Easier to define the control
volume as the duct boundaries and then you must integrate pressures.
Sheesh, Paul, I'm surprised you let him get away with this.  After all,
you're the lip suction guy :-)

Jeff Spitzer

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