LMNO Engineering - Flumes

And now, a message from our sponsor. I asked Ken about Parshall flumes calcs, and Bingo, here it is.

The fluid flow calculations website: http://www.LMNOeng.com. LMNO Engineering has a newsletter you can subscribe to from their site, what is reproduced below is from their newsletter.

Paul

Flumes for open channel flow measurement

Flumes, as used in this newsletter, refer to open channel flow measuring devices. Within the next few weeks, we will have a new calculation on our website for four different flume types - Parshall, Rectangular, Trapezoidal, and U-shaped.

Flumes are available in various widths. Usually, the maximum expected depth is fixed by the channel characteristics where the flume is installed, and in no case should exceed 2 m.

Flumes are designed to force a transition from sub-critical to super-critical flow. Such a transition causes flow to pass through critical depth at the flume throat. At the critical depth, energy is minimized and there is a direct relationship between water depth and velocity (and flowrate). However, it is physically very difficult to measure critical depth in a flume because its exact location is difficult to determine and may vary with flowrate. Through mass conservation, the upstream depth is related to the critical depth. Therefore, flowrate can be determined by measuring the upstream depth, which is a highly reliable measurement.

Our flume calculators will be based on ASTM and ISO standards for flumes. These standards were developed from theoretical relationships and modified by experimental observations.

Thank you for your interest in the LMNO Engineering website, Ken Edwards, Ph.D., P.E. (Owner/Engineer/Programmer) LMNO Engineering, Research, and Software, Ltd. <a href="http://www.LMNOeng.com">http://www.LMNOeng.com</a>

ASTM is American Society for Testing and Materials. ISO is International Standards Organization. Received on Tue May 08 23:37:00 2001