Random Aerodynamic Oddity of the Day Thread

[freebeard]

It's all about the frontal area.

OSI SIlver Fox:

http://www.velocetoday.com/wp-conten...7/4Z5U5258.jpg

[euromodder]

Did the Abarth have a rear engine ?
Looks like cooling scoops ...

On the Prius, it looks a roof indent rather than a bubble - trying to keep the air on the roof instead of spilling over to the sides ?

[freebeard]

Abarth built on IIRC Fiat and Simca chassis. I'd call the Prius a Pagoda Roof , like the Mercedes 240-300SL. It's opposite to the Dan Gurney bubble:

https://www.thetruthaboutcars.com/20...urneys-bubbly/

[gone-ot]

Gurney "bubble" was so a 6-foot-4-inch driver could physically "fit" into the cockpit and behind the wheel, it had nothing to do with aerodynamics.

[freebeard]

The pagoda roof is also not. It has to do with ingress/egress.

edit:
My favorite aero oddity for today; a brick shaped trailer.


http://justacarguy.blogspot.com/2018...-of-color.html

[kach22i]

MORE random pics...... - Page 4560 - Pelican Parts Forums


Still fluid dynamics, right?

[cRiPpLe_rOoStEr]

Originally Posted by kach22i

Still fluid dynamics, right?

Sure, since the rudder of a ship still has a similar function to the one in an aircraft

[freebeard]

It's interesting. I presume the blister on the leading edge is to reduce leeward turbulence. But why the step above and below it?

Oh no, Pelican Parts thread, there goes the rest of my afternoon.

[kach22i]

Originally Posted by freebeard

It's interesting. I presume the blister on the leading edge is to reduce leeward turbulence. But why the step above and below it?

Oh no, Pelican Parts thread, there goes the rest of my afternoon.

Notice as well, a slight twist at the top root.

This rudder is also acting like a vane straightening stator.

I'm assuming the smaller lower section is simply to reduce the stress, a cantilever moment arm is what the rudder actually is.

Remember, the swirling rotation of the water coming off the prop is best met at by right angles. However if they did that it would turn really well in one direction, and not at all in the other direction. This design is a compromise of some sort.

https://www.cambridge.org/core/journ...91B3DCBB77B7FE


http://www.wavefront.co.jp/CAE/PumpL...propeller.html

https://www.youtube.com/watch?v=jLLnbWEL7CU

http://www.hhscott.com/evinrude/choosing_a_prop.htm

[freebeard]

I'm gathering parts for a 1Kw gravity vortex watermill. I've got a washing machine motor, a housing made from parts (a dog kennel and a ventilator!) and two outboard motor propellers to choose from (3-blade metal and 6-blade plastic). All I need now is a shaft to connect the propeller to the motor/generator and an optional extension tube that necks down from 14" to ~7".

Do you think it would be better to square the tips of the blades and put it in a duct, or leave the tips and put it below the end of the duct?