Comparison of Methods for Predicting Discharge in Straight Compound Channels Using the Apparent Shear Stress Concept

Authors: TÜLAY ÖZBEK, MÜSTEYDE BADUNA KOÇYİĞİT, ÖNDER KOÇYİĞİT, KAĞAN CEBE

Abstract: Some experimental results from the SERC Flood Channel Facility at Hydraulic Research, Wallingford, UK, were used for computing apparent shear stress and discharge in symmetrical compound channels with varying floodplain widths. Three assumed interface planes (vertical, horizontal and diagonal) between the main channel and the floodplain sub-sections were considered. The apparent shear stresses across those interfaces were computed and the ratios of these stresses to the average main channel shear stresses were determined. Then discharge values in the sub-sections and in the whole cross-section were evaluated. The results showed that the performance of these computation methods depends on their ability to accurately predict apparent shear stress. Diagonal and horizontal division methods provided better results than the vertical division method, with the diagonal method giving the most satisfactory results.

Keywords: Compound channels, Division channel method, SERC-FCF, Apparent shear stress.

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