Author(s): C. Sousa; R. Lopes; J. Matos; M. Do Ceu Almeida
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Keywords: Reaeration; Circular channel; Vertical free-fall drop; Hydraulic jump
Abstract: Experimental investigations have been conducted in a hydraulic recirculating circular channel assembled at the Laboratory of Hydraulics of the Technical University of Lisbon, IST. In the present paper, the research is focussed on the reaeration at vertical freefall drops in circular channels. In particular, subcritical flow conditions were established at the downstream end of the flume leading to the formation of an hydraulic jump immediately downstream of the drop. The experimental results emphasise that the deficit ratio increases with the drop height or with the total energy loss in the drop and the hydraulic jump, and suggest that the influence of discharge is less significant. Empirical equations were derived for predicting the deficit ratio on vertical free-fall drops along with hydraulic jumps in circular channels, similarly to those proposed by other researchers for sewer drops (e.g., POMEROY and LOFY 1977, MATOS 1991, ALMEIDA et al. 1999).
Year: 2003