[gaiatechnician]

So, Just wondering if people can simulate the thing in my video. Airlift pump with and without the constriction. I develop very low pressure airlift pumps as a hobby and as a challenge. I use them in my garden to pump water (usually to circulate it to plants from a bucket up so it drips down through the soil. I think this grows things faster). One thing I did was test the limits of how high these could pump with very low pressure to power them. For instance I was able to pump 1.5 meters high with just 0.15 psi air pressure. In every really high pumping application I needed a constriction about 20 to 30 cm behind where the air was inputed to prevent a back and forth motion that wasted energy. I have never seen anything like it in designs from other people but it definitely works really well. I have used it for a few years now. Can anybody model this to explain it? (I have my own explanation but nothing, except intuition and observation to back it up). I did a video of one of my airlift pumps recently to demonstrate the effect. https://www.youtube.com/watch?v=LC41OjIcKow I used a little tap to close off the water in this video but usually I use a little length of aquarium air tubing to make a constriction. Thanks for the modeling help if anyone gives it a go. Brian White Victoria, BC Canada.