29. Drifting Velocity Sensor This scattergraph displays data from a flow monitor with a drifting velocity sensor. Note that the reported flow velocity drifts over a wide range without a corresponding change in depth. This flow monitor was equipped with an electromagnetic velocity sensor, which is subject to fouling from […]
Monthly Archives: November 2018
38 posts
28. Drifting Depth Sensor Most flow monitoring data can be described by the Manning Equation using either the Design Method, the Lanfear-Coll Method, or the Stevens-Schutzbach Method. Data that do not lie on a pipe curve generated by one of these methods indicate that either the hydraulics are different or […]
27. Undular Jump A hydraulic jump or other transcritical flow condition may reduce the accuracy of a flow monitor. However, this effect is not strictly limited to critical flow (Fr = 1), but may also occur within a wider range of near-critical flow conditions. Research by Chanson, Hager, and others […]
26. Hydraulic Jump This scattergraph is from a site that experiences a hydraulic jump. This condition occurs when flow transitions from supercritical to subcritical flow. In this example, the hydraulic jump is located upstream from the monitor at lower flow rates, and the subcritical side of the hydraulic jump is […]
25. Iso-Froude Lines The Froude Number (Fr) is a dimensionless number used to describe flow conditions and is analogous to the Mach Number defining supersonic flight. If the Froude Number is less than one, flow conditions are described as subcritical. If the Froude Number is greater than one, flow conditions […]
24. Sewer Amusement These data are from a flow monitor installed on one of three interceptors arriving at a wastewater treatment plant (WWTP). This unusual and entertaining pattern was created during a rain event when one of the larger interceptors overpowered this one. The Stevens-Schutzbach Method is used to define […]