Discharge coefficient of a semi-elliptical side weir in subcritical flow

Kaya N., Emiroglu M. E. , AĞAÇCIOĞLU H.

FLOW MEASUREMENT AND INSTRUMENTATION, vol.22, no.1, pp.25-32, 2011 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 22 Issue: 1
  • Publication Date: 2011
  • Doi Number: 10.1016/j.flowmeasinst.2010.11.002
  • Page Numbers: pp.25-32


A labyrinth weir is an overflow weir, folded in plan view to provide a longer total effective length for a given overall weir width. The total length of the labyrinth weir is typically three to five times the weir width. In this study, a semi-elliptical labyrinth weir was used as a side weir structure. Rectangular side weirs have attracted considerable research interest. The same, however, is not true for labyrinth side weirs. The present study investigated the hydraulic effects of semi-elliptical side weirs in order to increase their discharge capacity. To estimate the outflow over a semi-elliptical side weir, the discharge coefficient in the side weir equation needs to be determined. A comprehensive laboratory study including 677 tests was conducted to determine the discharge coefficient of the semi-elliptical side weir. The results were analyzed to find the influence of the dimensionless weir length L/B, the dimensionless effective length L/l, the dimensionless weir height p/h(1), the dimensionless ellipse radius b/a, and upstream Froude number F-1 on the discharge coefficient. It was found that the discharge coefficient of semi-elliptical side weirs is higher than that of classical side weirs. Additionally, a reliable equation for calculating the discharge coefficient of semi-elliptical side weirs is presented. (C) 2010 Elsevier Ltd. All rights reserved.