Monday, April 27, 2009

Fluid dynamics of the local stream

The first genuinely warm day of Spring. The Sun opens up the landscape into a buzzing, multi-hued repository of beauty and intricately detailed physical process. The garden is stratified by colour: three blood-red tulips surge vertically against an emerald background of lawn, hedge and tree, themselves shouldering an aquamarine sky.

Taking a walk to the local stream, limitless complexity abounds. Where the flow is shallow, and the bed is pebbly, a series of undulations appear in the surface flow; standing waves perhaps? Fronds of vegetation protrude into the waterway, and small vortices spin off their tips, passing a short distance diagonally down the streamflow. In places, the flow is narrow, and vegetation chokes both sides; here, the vortices cross-hatch the surface.

Some parts of the stream are silent and languid; others tinkle and babble, and here the flow is turbulent. Sudden irregularities and constrictions cause small waves to break, and jets to impact the water, trapping bubbles of air; cavitation creates bubbles of water vapour where the water impacts upon rock and stone; the bubbles oscillate, creating sound waves in the water, which propagate to the surface, and thence transmit to the air as a tranquilising murmur.

Each square metre of this totally unremarkable watercourse, is worthy of its own treatise; each unit area deserves its own magnus opus from a fluid dynamicist.


Sean said...

When I get home from a hard days toil I like to watch something totally pointless, something that anesthetizes the mind, reboot the old CPU.

Clangers is a favourite, Magic roundabout, or if I dont mind having to engage a few brain cells, Michael Bentines potty time.

Then cleansed and refreshed I can go out for a nice evening walk now the nights are longer, without having to rationalise the world that I see, and just delight in its aesthetic being.

Mine is a simple life :0)

Gordon McCabe said...

Ah, you see, there's where you're going wrong: it's the hard day's toil. If you didn't do that in the first place you wouldn't need to watch Ivor the Engine et al when you get home.

Sean said...

Dont count on it, I would probably extend the listings a little, but not much.

And anyway someone has got to pay the Chinese their money back.

Strangely enough I have this year noticed more butterfly than normal even though we are still having some very chilly nights. A hurricane in Antigua must be on its way?