Tricks to Decode Weird Looking Flow Survey Data.

Joseph Pang

ABSTRACT

This paper describes several procedures that utilize mean velocity profile, depth, velocity, and flow time series, and Froude Number to aid in the selection of flow survey locations and analysis of flow survey data.

These procedures are only applicable to flow survey data collected by Area/Velocity (A/V) flow meters as depth and velocity time series, and the resulting flow time series are the primary basis for analysis. In these procedures, the time series and theoretical results calculated from them by using Manning’s and Froude Number equations are plotted onto specially configured graphs. By noting the location of field survey data and their relative position to theoretical results on the graphs, the graphs can be used by engineers to identify key properties of the monitored flow such as flow regime, occurrence of hydraulic phenomena such as hydraulic jump and the magnitude of the resulting conjugate depths, and whether the flow is controlled or free. These types of hydraulic information of a flow survey location and properties of flow data are useful when the collected flow data are used for model calibration and other purposes such as hydraulic structure design and retrofit.


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