Rijke Tube Gauze Placement
Most recent answer: 12/26/2013
- Ayush (age 20)
The Wikipedia article on the Rijke mechanism is so nice that I think we should just steer you to it for the basics: .
There is actually a pressure node near the bottom since the tube is open. So by Rayleigh's description the sudden increase in pressure when cool air is heated by the gauze wouldn't drive the wave if the gauze were at the bottom. At the middle, a velocity node, there's no periodic velocity change, so you get almost no periodic driving from the heating of the air flow. In between there's some periodic velocity and some periodic pressure, so that's where the heating has a periodic component that can drive pressure changes that build up the wave. I think the exact optimum position varies as the ratio of the periodic velocity changes to the steady upward flow changes.
(published on 12/26/2013)