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.

3 comments:

  1. 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)

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  2. 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.

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  3. 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?

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