Author(s): M. M. Clark; D. M. Admiraal; J. A. Gonzalez-Castro
Linked Author(s): Juan A. González-Castro
Keywords: No Keywords
Abstract: A 6.26:1 scale model of a control structure comprised of a weir and a gated culvert was built to study the shifting of hydraulic control between components over the range of operating conditions of the structure. Records of concurrent measurements of headwater and tailwater stages, sluice gate openings and discharges made at the prototype structure were available for model calibration; however, measurements of head losses associated with the inlet weir, sluice gate, and corrugated culvert were not available and could not be isolated from the prototype measurements. Fortunately, discharges were measured in the prototype culvert using an Acoustic Doppler Flow Meter (ADFM), which relies on the measurement of velocities to estimate discharge. In this paper, calibration of culvert roughness in the physical model based on ADFM data is discussed. The prototype culvert roughness was assessed from the velocity profiles measured with the ADFM. The transformation used to transform velocity profiles measured with the ADFM to cylindrical coordinates is described in the paper. Furthermore, the roughness of corrugated culverts resembles d-type roughness (typical of surfaces with riblets and wavy boundaries) more than k-type roughness (typical sand-grain roughness). The choice and placement of roughness elements in the model culvert and the dynamic similarity between the velocity profiles in the model and those in the prototype are also discussed.
Year: 2009