Aerodynamic Streamlining Mini-Course

[freebeard]

Look at the engineering Dyson put into their fan to keep it quiet. It has Helmholtz Resonators (sounds like something out of Star Trek). The hypothetical aircraft would shriek like a banshee. You may as well put a jet engine in the middle. Presto, you have a modern high-bypass turbojet aircraft engine.

The Dyson fan uses Coanda nozzles. Those can be applied to vehicles. The paper, Advanced Aerodynamic Devices to Improve the Performance, Economics, Handling and Safety of Heavy Vehicles, is currently paywalled but it's quoted here.

Hi, Sven7.

[aerohead]

Originally Posted by Otto

I've wondered if such phenom could be used to propel an aircraft.

I also wonder if instead of a hollow ring foil, linear airfoils with air ejection could be used for spoilers and diffusers on the rear of cars, to fill and fair the turbulence behind the car, reducing drag.

Thoughts?

*I think the high-bypass turbofan uses less power (fuel) so they've settled on that for now.
*For cars,I think Georgia Tech is still trying.So far the 'pump' uses more energy than is saved by the blown/suctioned modifications.
The Japanese have a STOL aircraft which uses slot technology.It requires a 5th jet turbine engine to make the wings work.

[freebeard]

Have you heard anything recently out of Georgia Tech/Englar?

These experimental results show overall aerodynamic drag reductions on the Pneumatic Heavy Vehicle of 50% using only 1 psig blowing pressure in the plenums, and over 80% drag reductions if additional blowing air were available.

This sounds like the requirement is mild, but it doesn't talk about the volumes involved. I have 1500cfm of hot air available under my back bumper but I don't know at what pressure.

[Big Dave]

Excellent stuff, Phil.