Dan Ruggirello wrote:

Hi Paul,
Here is profile R7.  My rational here was to use your concave wedge since it seems like it does a
good job of evening out the pressures across the radiator.  Also, in order to get a bit more flow

>from the left of the radiator, the opening behind the vent takes advantage of the vaccuum

developed from the air flow around the cowling, drawing more air through the left of the
radiator.  Actually, it looks like a bit too much air!  This configuration leaves the question of
how and where to install cowl flaps.  I think I will try a run with a full vent to see how that
differs from this one.

Dan

I am a bit suspicious of that velocity data under the aircraft. I think the boundaries
are too close or the overall flow field is not correctly modeled.
Try increasing the over all length of the model and moving the lower boundary
further away from the bottom of the aircraft. Twice as far. In fact I still
don't think it is velocity at all. I still think those plots are pressures.
Something wrong there. Makes good sense if you consider these plots pressure.
The pressure plots are believable on the other hand.

Also try the flaps at a
15 degree angle instead of 30 degrees as I initially drew. I can revise
the drawing if necessary. The concave diffuser shape was recommended
by Kay's & London. I also did some full scale test with that configuration with
good results several years ago.

If you can scan that paper and send it to me perhaps we can get it translated.

Paul Lamar

I forgot something. Make the lower boundary horizontal as well.
That will more closely simulate the real world.


Paul Lamar

Can Dan analyze this?  It is a pusher LEZ, this is a very approximate
drawing of my oil cooler installation.  I've probably tried a dozen
different things over the years and oil still doesn't cool very well.
The exit on top of the cowl is now basically open, just several  "fixed
cowl flaps" at a 45 degree angle.

Perry

Perry, what is the distance from the scoop opening to the leading edge of
the strake? That will have a strong effect on the boundary layer thickness
and consequently the simulation. Perhaps you should redraw it to scale.

Paul Lamar

 
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