Hydraulic investigation of venturi flumes

Venturi flume is a very popular measuring device. A particularly attractive version of such a device is a standing-wave-flume, as this enables determination of liquid discharge by one-point depth measurement only. However, it is necessary to underline, that some essential simplifications must be introduced into the theoretical description of this case. The paper contains the results of the control investigations of six existing Venturi flumes, installed in three functioning sewage-disposal-plants in Poland. It was shown, that some important mistakes can be committed, when somebody plans such a flume. These mistakes worsen the flow measurement accuracy. In conclusion it was stated that the standing-wave-flume must be designed very carefully, with the use of gradually-varied flow equations. An alternative, which is worth using, is a Venturi flume with two-point depth measurement.