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This paper investigates experimentally the changing of a hydraulic characteristic of combined hydraulic structure owing to the existence of dike structure. Different models of combined structures are used with rectangular gates and rectangular weirs, respectively. Also, the location of the dike structure is considered. A dike is located upstream, downstream, and on both sides of the combined hydraulic structure. Discharge quantity, average downstream water depth, discharge coefficient, and Reynolds number are adopted to describe the alteration in hydraulic behavior of a combined structure. While the relation between upstream Froude number and downstream Froude number, as well as the relation between downstream Froude number with distance, are employed to illustrate the interactive response between dike and combined structure, From the study, the relation between Froude number at downstream and non-dimensional downstream distance as well as the relation between non-dimensional downstream water depth and non-dimensional distance reveal how the dike location effects on water depth and flow velocity, which lead to a change in the type of flow. Here, the dike position is shared in the form of a hydraulic jump at downstream of the combined structure. The experimental data were statistically analyzed to ensure their validity and reliability. The importance of this study is concentrated on how the location of the dike structure is shared in the alteration in the hydraulic characteristics of the combined hydraulic structure, especially the rise in the water depth at downstream, in addition to the change in the hydraulic jump height and energy losses. [ABSTRACT FROM AUTHOR]

A composite hydraulic structure can be described as a discharge structure constructed inside a river or an open channel. This experimental study is targeted at investigating the performance of the composite hydraulic structure in consideration of the existence of the longitudinal obstacle in the downstream region of the composite hydraulic structure. This study adopts two different lengths of the longitudinal obstacle. In addition, three different cross-sectional areas of the obstacle in the lateral direction are adopted. Also, the gate of a composite structure has a half-ellipse shape, while the weir of a composite structure has rectangular, triangular, and parabolic shapes, respectively. Seven cases are investigated experimentally. Here, six cases included the longitudinal obstacle, while the last case was without it. The influence of downstream Froude number on the average downstream water depth, downstream flow velocity, upstream Froude number, Reynolds number, and actual discharge is investigated. Also, the relationship between Reynolds number and downstream flow velocity, actual discharge and downstream flow velocity, discharge coefficient and upstream Froude number, discharge coefficient and Reynolds number, discharge coefficient, and actual discharge is investigated, respectively. The results illustrated that the longitudinal obstacle has a moderate influence on the hydraulic characteristics of the composite hydraulic structure regardless of the obstacle length and the obstacle cross-section area. Finally, the hypothesis test is performed to demonstrate the feasibility of the longitudinal obstacle. [ABSTRACT FROM AUTHOR]

Experimental investigations are carried out to study the physics of the flow that passes weirgate hydraulic structure and encounters obstruction with or without installation of downstream opening. This study approaches the comparison between two different options; the first option deals with free flow condition while the second option deals with submerged flow condition. Various cases are performed considering different hydraulics variables and dimensions variables to evaluate the existence of obstruction with or without openings. Overall the flow pattern is more sensitive to the presence of obstruction at downstream region than in its absence. The hydraulic variables that are considered in the study are divided into dimensional variables such as discharge, downstream flow velocity and water depths at downstream and non-dimensional variables such as discharge coefficient, Froude number and Reynolds number. The obstacles which are used in this study have variable heights with constant width and length. Constant spacing between the obstacles is adopted. Different arrangements of obstacles are considered in this study and it is found that a significant and reasonable result is different among the cases. The effect of rectangular opening in the obstruction on flow pattern is studied. The effect of obstacles with rectangular opening gives a noticeable result in the assessment of the discharge coefficient of the composite hydraulic structure. [ABSTRACT FROM AUTHOR]