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.


7 comments:

Zouk Delors said...

Garibaldi? Fluid dynamics? That takes the biscuit!

Synchronicitously (synchronously?) a "fluid dynamicist" was Jim Al-Khalili's guest on BBC R4's The Life Scientific this morning. Amongst other things, she helps the police work out where and when bodies found in rivers and canals must have entered.

Mike C. said...

Well, I'm glad someone chose to bite on that one, but will anyone remember Semprini?

Mike

Zouk Delors said...

Of course! Noted for the fluidity and dynamism of his music.

Mike C. said...

And for a Monty Python sketch, of course...

Mike

Gavin McL said...

It's Osbert Reynolds you're looking for - he was interested in the transition between laminar and turbulent flow. He's most famous (amongst fluid dynamicists ) for his number which you can use to identify when flow will become turbulent.

Mike C. said...

Gavin,

Wot, not even Reynoldi? Where's the fun in that? Well, at least we've got his number!

Mike

Zouk Delors said...

Haha! Yes, I'd forgotten about that. Let me know if you need bailing out!