Study of the Inception Length of Flow over Stepped Spillway Models

  • S Munta
  • JA Otun
Keywords: Stepped spillway models, skimming flow, development length, practical method, chute angle


This study is the modification of Bauer’s development length in order to determine the excess in his length which has not been investigated by earlier researchers. The observations were performed in the non-aerated flow region of wooden stepped spillway models fabricated and installed at the Hydraulics Laboratory of the Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Zaria-Nigeria. A total of 40 experiments were conducted over three different chute geometry to determine Bauer’s development length which were plotted on a drawing paper to a scale of 1:1 to obtained the development length in this study. The results showed that the inception (development) length increases as the unit discharge increases and it decreases with an increase in both stepped roughness height and chute angle. The ratio of the development length, in this study, to that of Bauer’s was found to be 4:5. Finally, SMM-5 produced the least velocity of flow and the highest depth of inception; indicating that it could be employed optimally, considering this study, in curbing or preventing cavitation as a flood controls structure.

Research papers

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eISSN: 2467-8821
print ISSN: 0331-8443