STUDY THE EFFECT OF ASPECT RATIO AND INLET CONFIGURATIONS ON THE HYDRAULIC OF BOX CULVERT UNDER INLET CONTROL.

The feature and configuration of culvert entrance beside the aspect ratio (span/rise) have a key role in determining the hydraulic performance of culver. The conveyance along with the permitted height of head water can be determined mainly by the effect of the entrance factors on it. The present study aim to investigate the entrance feature and configuration on the hydraulic performance of culvert operated at inlet control for both unsubmerged and submerged entrance. Different aspect ratios with just head wall of square edges entrance have been tested experimentally by a wide range conditions to perform both unsubmerged and submerged flow. However, a new shape of inlet transition structure that proposed by Howes et al., 2010 have been adopted as the inlet approach to achieve a gradual contraction of stream lines before entrance. The results showed that improvement in performance through adoption of the actual measurements of contraction coefficients which leads to extract a new practical equations and design charts. However, the traditional limitations of the zone between unsubmerged and submerged flow at the entrance were developed through using a new shape of the inlet transition as the approach section to square edges entrance.