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.

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Published in: on May 2, 2009 at 7:05 pm  Comments (2)  

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2 CommentsLeave a comment

  1. Yes, but where are the fluid dynamicists when you need them?

  2. They’re a turbulent and unpredictable bunch.


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