Скачать или смотреть Fluid Mechanics Lab: Flow Over a V-Notch-Exp07

The most common types of sharp-crested weir are the rectangular weir and the triangular weir.
The triangular or V-notch weir is preferable to the rectangular weir for the measurement of widely variable flows. In the case of a rectangular weir, the total weighted perimeter does not vary directly with the head, as the length of the base is the same for all heads. Therefore, the coefficient of contraction, which depends on the wetted perimeter, is not constant for all heads. But in the case of a V-notch, there is no base to cause contraction, which will be due to the sides only. The coefficient of contraction Will, therefore, be a constant for all heads. For this reason, the V-Notch is the most satisfactory type for flow measurement in canals.

Practical application

The V-notch weir is preferred when small discharges are involved because the triangular cross-section of the flow `nappe' leads to a relatively greater variation in the head. V-notch weir has the advantage that it can function for a very small flow and also measure reasonably larger flows as well.




#FluidMechanicsLab
#FMLabExperiment
#FlowOverVNotch