Weirs

(Short) broad crested weirsThin plate (sharp-crested) weirs

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Weirs

• (Long) broad crested weirs Streamlined above crest A. (long) broad crested weirs: water

downstream influences negatively the discharge B. (long) broad crested weirs: water

downstream does not influence the discharge

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Weirs

• (short) broad crested weirs• Not streamlined above crest (no hydrostatic pressure on

crest)

• Measuring the discharge with Thin plate (sharp-crested) weirs

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(Short) broad crested weirs

• Not stream lined above crest• Effects of no stream lining in discharge

coëfficient• h > ⅔H• h ≤ ⅔H• Shape of the crest

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Thin plated weirs

• Used for discharge measurement• Sharp crest• H = h• Measure H up stream where it is stream

lined• Pressure under nappe is atmosferic

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Thin plated weirs

• Rehbock weir• Romijn weir• Weir of Cipoletti (trapezoidal)• Circular shaped weir• Thomson weir (V-shaped)

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Films Macedonië

• Hydrosystem “Strezevo”• Film field trip september 2009• http://vimeo.com/album/157465/video/7895

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