In this study, the effect of suspended load transport on the characteristics of submerged hydraulic jump (SHJ) in a rectangular channel was investigated experimentally. Sediment concentration and jet Froude numbers in the range of 0.424%-16.15% and 1.93-4.96, respectively, were considered. Tow grain size 0.15 and 0.03 mm were used in the experiments. Characteristics of submerged hydraulic jump including velocity and concentration distribution, length of jump, the submergence depth on the gate and the energy dissipation were studied. The results showed that the submergence depth on the gate and the energy dissipation are constant by increasing of sediment concentration. The length of the jump at the presence of suspended sediment is smaller than those due to clear water flow. Also, suspended sediment by decreasing of flow resistance is made to decrease flow velocity.

One of the ways to improve characteristics of hydraulic jump is using corrugated beds in location that hydraulic jump is occurred as the corrugated beds by causing strong turbulence in flow, increased Reynolds stress and reduced velocity and second depth of jump. In this study, by applying VOF method and turbulent models of k-e and RNG k-e, a series of hydraulic jumps on corrugated bed by 13 mm height and 68 mm wave length in a range of Froud number from 3.5 to 8.5 were performed and results were compared by some experimental data.Results of this research showed that the proposed model by applying RNG k-ε turbulent model that has fine ability to modeling flow with high shear stress, estimated second depth, length of jump and velocity distribution of hydraulic jump on corrugated beds, very well. In addition, the results indicated that the numerical model could estimate shear stress coefficient of jump on corrugated bed close to the experimental results. The estimated value of shear stress coefficient on corrugated bed by numerical model was 10 times of this value in classical hydraulic jump.

Many studies have been conducted on the characteristics of hydraulic jumps over horizontal basins. On sloping basins, however, few such studies have been performed so that issue requires more investigation. A significant number of studies has also been conducted on basins with positive slopes but comparatively few have been carried out on basins with negative slopes. This study was carried out to determine the characteristics of hydraulic jumps over negative slopes with negative steps. The results revealed that negative steps have significant effects on the stability of hydraulic jumps, while also increasing their length and conjugated depth.  

Hydraulic jump stilling basins are among energy dissipators which commonly designed at the downstream of spillways, chutes and sluice gates. The slab of the structure is effected by the hydrostatic pressure and uplift pressure in which during operation fluctuate. Therefore the effect of pressure fluctuation is an important aspect of slab design in which have not been considered in the past. In this study an extensive experimental program have been conducted to clearly define new design criteria. The experimental set-up consisted of a flume 20.0m long, 0.9m width. Tests were performed at the downstream of ogee spillway l.2m height. Six different discharges ranged from 30 to 170 lit/sec applied to produce different discharges numbers ranged from 5 to 12. For each test, the pressure fluctuation was recorded every 30 second resulted 108000 data. To determine the criteria for slab stability, three slabs in different sizes made of concrete were installed in the test section and each slab was tested under different hydraulic conditions. Applying the dimensional analysis, a general relation was developed. Using this relation and experimental data a formula was developed to be applicable for the design of slab at the base of hydraulic Jump stilling basins. The experimental program and results are presented. A comparison of the new method with previous method is presented also.

Hydraulic jump is an effective phenomenon which is used for dissipation of excess kinetic energy downstream of hydraulic structures such as drops, spillways, chutes and gates. During the past decades many studies have been conducted on characteristics of hydraulic jump on smooth floor. Recent studies have shown that corrugated bed can reduce the cost of hydraulic jump stilling basins. Therefore, the main goal of this study is to conduct an extensive experimental study program on this subject. Four different beds of trapezoidal corrugated shapes were tested under different Froude number ranging from 4 to 12. The results show that the required tail water depth and the length of jump have been reduced as compared to the jump on smooth floor. Computation of shear stress also shows that the bed shear stress on rough floor is 10 times the shear stress of classical jump. During the experimental tests, the velocity profiles were measured and it was found that the centerline velocity of the incoming jet is reduced which depends on the entrance velocity and the distance from the gate opening. The results of this study reveal that trapezoidal corrugated floor can reduce the cost of stilling basins.

Hydraulic jump phenomenon is a rapid variation in flow conditions that occurs during the transition of the flow from supercritical to subcritical conditions. During the hydraulic jump, flow depth rapidly increases within a short distance. The depth increase is accompanied by a relatively high energy loss and leads to a sharp decrease in flow velocity. Determination of hydraulic jump position in the construction of such structures as spillways and lower floodgates in dams, where the hydraulic jump is formed at the downstream, has particular importance in engineering perspective. Due to the relatively high costs of constructing basins for controlling the hydraulic jump, many researches have been conducted regarding applied methods for cost reduction, ensuring that the jump occurs at a specific location with the maximum energy dissipation. Controlling the hydraulic jump via the flow, itself, can be very cost effective. So far, considerable research has been conducted in this regard. The simplest type of hydraulic jump is the Classic (Type A), which happens in horizontal rectangular channels. The aim of present study is investigating the effect of the momentum transferred from rapid free jet on the hydraulic jump characteristics. For this purpose, a jet impingement was conducted at six different flow rates and four jet angles. The hydraulic jump characteristics (i. e., the primary and secondary depths, energy dissipation, and jump displacement) were compared, with and without the jet, at 7 primary Froude numbers. The experiments were conducted inside a laboratory of Mashhad University flume with the following dimensions: length=5 m; width=7. 5 m; and height=17. 5 cm. The flume has an adjustable slope which was set as 0. 0025 in the experiments. The flow rate was determined via the channel measuring system. To eliminate the scaling effect on the obtained results, several experiments were conducted with horizontal bed and rectangular channel to create hydraulic jumps to obtain the conditions for the control experiment. A control gate was implemented at flume downstream at the distance of 3. 75 meters from the upstream floodgate, in order to control and stabilize the classical hydraulic jump. The fast water jet was created via a nozzle installed at the end of the pipe attached to pumping system. The rectangular nozzle was 6. 8 cm long and 1. 5 cm wide. This device was fitted at the distance of 40 cm from the upstream gate. Four angles were considered for the jets with respect to the flume floor: 15, 30, 45, and 60 degrees. Six flow rates were produced for the jet. In the experiments, seven classical hydraulic jumps at various Froude numbers, namely, 1. 98, 2. 18, 2. 68, 3. 58, 3. 73, and 4. 76 were created and subsequently, fast impinging water jets were applied to them at different flow rates and angles. Many experiments have been conducted on a small physical model for qualitatively studying the effect of momentum transfer to a hydraulic jump by a fast jet. Although the results obtained from a small model cannot be generalized to the main prototype, the working process can be very helpful in larger models. By entering the jet into the flow under supercritical conditions, the hydraulic jump was moved along the upstream of the flow. At a constant jet angle, an increase in the jet flow rate would lead to a corresponding increase in the jump displacement. At constant Froude number and constant angular position of the jet, increasing the jet flow rate would lead to an increase in the secondary hydraulic jump depth (y2), as well as an increase in the dissipated energy. At constant jet flow rate, increasing the jet angle would decrease the secondary depth (y2) and the dissipated energy. At constant angular position of the fast jet, increasing the jet flow rate would lead to a corresponding increase in the jump length (Lj). By increasing the jet angle, the hydraulic jump length (Lj) follows a descending trend. At low Froude numbers, the dissipated energy is greater. At each hydraulic jump, a different optimum jet angle is obtained (depending on the main channel flow rate and the jet conditions) which shows the correct impingement point. Froude number (effect of gravity in the main channel) variations had the greatest and the jet impinging angle had the least effect on energy dissipation. The impingement point, where the jet hits the flow in the main channel, is significant in the displacement of the hydraulic jump and also the dissipated energy. At lower Froude numbers, the sensitivity of energy dissipation to Froude number dramatically decreases with increasing Froude number until reaches to the mean value. Thereafter, the sensitivity, once again, increases with a sharp slope.

The hydraulic jump has many usages in transport and treatment of water and wastewater. It may be considered macroscopically as a rapidly varied flow with strong vortices which generate macro turbulent fluctuations. The pressure fluctuation due to turbulence must be carefully considered in designation of hydraulic structures. In addition, cavitation, abrasion, and vibration due to the intense turbulence and pressure fluctuation may also contribute significantly to damage of a stilling basin. This paper discusses the characteristics of pressure fluctuation in submerged hydraulic jump downstream of spillways and also the effects of submergence ratio on the pressure fluctuation. The experiments were carried out in a rectangular conduit (constituted from a30o spillway, 1. 8m in height and a horizontal flume with 0. 3m width and 3m length), for the Froude number of 7. 07 and also different ratios of submergence. Pressure data were recorded by pressure transducers having sampling rate of 100 Hz. Experiments show that intensity of pressure fluctuation on the hydraulic jump bed is a function of Froude number a relative distance from basin’ s beginning and submergence ratio. Increasing submergence ratio decreases the coefficients of pressure fluctuation (C􀭮 􀬿 , C􀭮 􀬾 , C􀭮 􁇱 ), so that increasing the s. r. from 1 to 2, the C􀭮 􀱣 􀱗 􀱮 􁇱 decreases 89%. Also, the coefficient of standard deviation C􀭮 􁇱 and the extreme coefficients of pressure fluctuation C􀭮 􀬿 and C􀭮 􀬾 decrease by increasing the s. r., and maximum value of C􀭮 􀬿 and C􀭮 􀬾 occurs in the range of X/Y1  20. Therefore, this range has more importance from the structural designation view and the higher ratio of submergence supports the higher confidence for designation.

One of the most frequently encountered cases of rapid varied flow is the hydraulic jump. It occurs when a supercritical open channel flow changes into sub critical flow. In the present research, the experimental study of the hydraulic jump on seven sinusoidal corrugated beds with different wave steepness. The wave steepness of sinusoidal corrugated beds is in the range of 0.1667 to 0.75 and Froude number was in the range of 4.5 to 12.26.The results showed that the tail water depth of a jump on a corrugated bed is about 20% smaller than that on smooth bed in Froude number 12 and the length of jump on corrugated beds is about 35% less than that for smooth bed.

Due to limited resources in the field of hydraulic jump in compound channel, this laboratory research was performed by creating a stable and symmetrical jump.The study was implemented on an experimental channel with a length of 10 m, a width of 1 m, and a height of 0.8 m in the Hydraulics Lab at the Gorgan University of Agricultural Sciences and Natural Resources. 6 meters of the total length of the channel has been transformed into a composite channel. Also, the main cross-section and floodplains had adjustable depths and widths. The present study examined the effects of the relative width and initial Froude number. Three relative widths and three initial Froude numbers were studied in a total of nine tests. In each test, the initial Froude number was set to induce a hydraulic jump by changing the opening of the upstream opening height at a given flow rate.The present work experimentally induced hydraulic jumps in compound open channels and quantified the physical properties of hydraulic jumps (e.g., conjugate depths and hydraulic jump length) by point velocity, flow rate, and flow velocity measurements. The results indicate that the physical and hydraulic characteristics of the observed jump are different from the classical type and the use of classical jump equations leads to error.

In this paper differential equations of spatially varied flow with lateral outflow have been solved by the fourth order Runge-Kutta method. One of the probable conditions that requires a complicated analysis is the case in which a hydraulic jump occurs in the reach of the side weir. In this case, unlike other cases, which requires only one boundary condition for either upstream in supercritical flow or downstream in subcritical flow, two boundary conditions for both upstream and downstream are required. One of the significant issues in the analysis is to determine the location of hydraulic jump and lateral outflow. In this study, a numerical method based on an iterative procedure has been introduced to determine the location of hydraulic jump and lateral outflow. This method has been linked to the fourth order Runge-Kutta method to obtain the water surface profile. One example is introduced to illustrate the ability of the model.