RBC Flume Design
Two design goals determined the shape of the RBC flume: ease of manufacture and conformance to the normal shape of irrigation ditches and furrows.
As a result, the RBC flume has flat, constant trapezoidal cross-section and a flat-sided ramp rising up in the throat.
The trapezoidal cross-section make the RBC flume easier to adapt to existing channels (unlike the Parshall) as it eliminates the need to either set the flume above the channel floor or modify the downstream channel.
RBC Flume Dimensions
RBC flumes are scale models of each other with the base width the determining factor for all other dimensions.
The dimensions for the RBC flume are set for in:
- Clemmens, A., Bos, M., and Replogle, J., Portable RBC Flumes for Furrows and Earthen Channels, Transactions of the ASAE, Vol. 27, No. 4, July/August 1984
Note that the dimensional tolerances of the throat are critical as a different of 1% error in throat cross-section will cause an error in the discharge measured of 1%.
Throat length and ramp length have more margin for dimensional tolerance, but the intersection between the flume floor / ramp / throat must be distinct.