جستجوی مقالات مرتبط با کلیدواژه "طول پرش هیدرولیکی نسبی" در نشریات گروه "آب و خاک"

In the last decade, the use of gabion structures in hydraulic engineering for stabilizing the structure due to its high density and weight has become widespread. Also, the material's roughness and porosity cause it to be used in energy dissipation and drainage projects. This study evaluates the relative energy dissipation of gabion structures downstream of the ogee spillway in the conditions of a submerged hydraulic jump. The evaluated parameters in this study were Froude number, gabion height, gabion thickness, and material diameter. The experiments were performed with three average diameters of 1.5, 2.2, and 3 cm for rock material, three gabion heights of 10 and 20 cm, and Max. The end sill heights were 10, 20, and 30 cm. The operated discharges were regulated from 20 to 40 l/s. The results showed that by decreasing the average diameter of gabion aggregates, the amount of relative energy dissipation increases in all tested models, so that in gabion with a 1.5 cm average diameter of aggregates, the amount of energy dissipation increased by 3.6% in comparison with using the diameter of 3cm for the average diameter of the material. Increasing the height of the gabion to the extent that the flow is entirely inward can have up to 33% more relative energy dissipation than the gabion with a height of 10 cm. Also, by increasing the diameter of the gabion from 10 cm to 30 cm, relative energy dissipation increases up to 15%.

In this research, experimental evaluation of different hydraulic conditions on the performance of gabion sill in dissipating energy at downstream of Ogee spillway has been investigated. The parameters evaluated in this study included: Froude number, sill height, the amount of opening in the sill width and the diameter of the aggregates. The experiments were conducted by using flow discharges of 20 to 40 liters per second with two heights of 5 and 10 cm and openings of 10, 15, 20 and 30 cm in fixed sill widths with and without openings. The results showed by increasing the height of the sill, the relative length of the hydraulic jump increases and the amount of relative energy dissipation also increases. Also, by increasing the diameter of aggregates, the relative length of hydraulic jump and the amount of relative energy dissipation decreased. The highest amount of energy dissipation was related to aggregates with an average diameter of 1.5 cm in which the amount of energy dissipation and the length of hydraulic jump were 9 and 8.3 % more than the ones in 3 cm diameter of aggregates, respectively. The results also showed creating an opening and increasing it across the sill reduces the relative energy dissipation. So that the relative energy dissipation in the gabion with 30 cm opening was about 7% and its relative hydraulic jump length was about 9% less than the ones in sill without opening.