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Rehbocks Formula:
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Rehbocks Formula is an empirical equation used to calculate the coefficient of discharge for weirs. It provides a more accurate assessment of discharge coefficient by accounting for the relationship between water height above the weir crest and the crest height itself.
The calculator uses Rehbocks Formula:
Where:
Explanation: The formula accounts for the ratio of water height to crest height and includes a correction factor for very small water heights.
Details: Accurate coefficient of discharge calculation is crucial for determining actual flow rates over weirs, designing hydraulic structures, and conducting water resource management studies.
Tips: Enter height of water above crest and crest height in meters. Both values must be positive and non-zero for accurate calculation.
Q1: What is the typical range of coefficient of discharge values?
A: For sharp-crested weirs, the coefficient of discharge typically ranges from 0.60 to 0.75, depending on the weir geometry and flow conditions.
Q2: When is Rehbocks Formula most applicable?
A: Rehbocks Formula is most applicable for rectangular sharp-crested weirs with moderate to high head-to-crest ratios.
Q3: What are the limitations of Rehbocks Formula?
A: The formula may be less accurate for very low head-to-crest ratios or for weirs with significant approach velocity effects.
Q4: How does water temperature affect the calculation?
A: While Rehbocks Formula doesn't explicitly account for temperature, water properties (density, viscosity) change with temperature, which can indirectly affect discharge characteristics.
Q5: Can this formula be used for other weir types?
A: Rehbocks Formula was developed specifically for rectangular sharp-crested weirs and may not be accurate for other weir types such as V-notch or broad-crested weirs.