Tuesday, 22 March 2016
The Semprini Effect
These two contrasting scenarios – bright, rushing water and stagnant scum – are immediately next to each other, either side of the sluice that still exists on the Itchen Navigation, where St. Catherine's Lock and water-wheel used to be. You can stand on the lock, look down one side and see a grim accumulation of whatever has drifted downstream, and on the other be dazzled by the gleam of sunlight dancing on the foam and spray of a violent torrent of water. This has something to do with a principle of fluid dynamics established by Bernoulli, Venturi, Semprini, or possibly Garibaldi – one of those guys. Whoever, you really don't want to fall in, either side.