Water-drawing Nozzles. Based on the Venturi effect, this nozzle uses the speed of the propelled water to draw water from the basin which is then mixed with the initial stream to form a much greater mass of water than before. Looking at the diagram the jet of water discharged out of the central pipe is seen to draw in the water around the pipe. This effect causes an under-pressure that draws water from the basin. The jet propelled through the pipe when mixed with the drawn water forms a large mass of water discharged over the nozzle.
The first outcome is that there has to be a means of controlling the water level in the basin of the fountain to prevent the diameter and height of the water jet from fluctuating. But as the jet falls back into the basin, it causes waves and the waves create continuous changes in the level and consequently a fluctuation in jet diameter and height. To avoid this effect, a wave-deterrent needs to be provides (later we will look at different available systems) but there are those who claim that fluctuating jets are more "lively" and dynamic.
