Academic literature on the topic 'Submerged jump'
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Journal articles on the topic "Submerged jump"
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Ghaderi, Amir, Mehdi Dasineh, Francesco Aristodemo, and Ali Ghahramanzadeh. "Characteristics of free and submerged hydraulic jumps over different macroroughnesses." Journal of Hydroinformatics 22, no. 6 (October 14, 2020): 1554–72. http://dx.doi.org/10.2166/hydro.2020.298.
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Abstract The present study deals with numerical simulations of the free and submerged hydraulic jumps over different shapes of roughness in various roughness arrangements and different Froude number conditions. The models were studied using three roughness shapes, i.e. triangular, square and semi-oval for 0.2 < T/I < 0.5, where T and I are height and distance of roughness, respectively. The results showed that the numerical model is fairly well able to simulate the free and submerged jump characteristics. The effect of roughness plays a role in the reduction of the relative maximum velocity which is greater in the submerged jump. The thickness of the boundary layer for both free and submerged jumps decreases with increasing the distance between the roughnesses. Triangular macroroughness has a significant effect on the length of the jump and shortest length with respect to the other shapes. The reduction in the submerged depth ratio and tailwater depth ratio depends mainly on the space of the roughnesses. The highest shear stress and energy loss in both jumps occur in a triangular macroroughness (TR) with T/I = 0.50 compared to other ratios and modes. The numerical results were compared with previous studies and relationships with good correlation coefficients were presented for the mentioned parameters.
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Zare, H. K., and R. E. Baddour. "Three-dimensional study of spatial submerged hydraulic jump." Canadian Journal of Civil Engineering 34, no. 9 (September 1, 2007): 1140–48. http://dx.doi.org/10.1139/l07-041.
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A three-dimensional (3D) study of spatial submerged hydraulic jumps (SSHJs) was carried out using a physical model for Froude numbers Fr1 = 2.00 and 3.75 and width ratios α = 0.20 and 0.33. Three orthogonal components of the velocity field were obtained with an acoustic Doppler velocimeter (ADV). The 3D velocity field has indicated that the jump consisted of a central jet-like flow, close to the channel bottom, surrounded by vertical and horizontal circulations (rollers). The circulation was predominantly in vertical planes in the channel central region of the flow and in horizontal planes close to the walls. Vertical and horizontal profiles of stream-wise velocity characterized the 3D roller with two length scales, Lrv and Lrh. The strength of the roller was stronger close to the walls than at the centreline of the jump. Sequent depth and energy head loss for submerged symmetric hydraulic jumps are discussed in terms of the submergence ratio S = y3/y2.Key words: hydraulic jump, spatial, submerged, roller length, sequent depth, energy dissipation.
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Abdel-Gawad, Sameh M., and John A. McCorquodale. "Analysis of the submerged radial hydraulic jump." Canadian Journal of Civil Engineering 12, no. 3 (September 1, 1985): 593–602. http://dx.doi.org/10.1139/l85-067.
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Most of the research work on hydraulic jumps has dealt with their macroscopic behaviour. The important parameters in these studies were the sequent depth ratio and the jump length required for stilling basin design. Unfortunately, the internal flow in submerged radial hydraulic jumps has received very little attention. A complete mathematical model of the internal flow would permit the modeller to assess the possible scale effects in a physical model and to better estimate the cavitation potential.This study treats the internal flow characteristics of the submerged radial hydraulic jumps under different submergence and operating conditions. A numerical model based on the strip integral method is used to solve the governing momentum and continuity equations. The numerical technique uses velocity shape functions to permit the partial integration of the equations of motion. A Gaussian velocity distribution is used in the mixing zone and the power law is used in the inner layer. The model predicts the velocity distribution, water surface profile, decay of the maximum velocity, variation of the surface velocity, sequent depth ratio, jump length, and energy loss.A comprehensive experimental program was conducted in an expanding Plexiglas flume with a total angle of divergence of 13.5°. The results were used to calibrate and validate the model. The model predictions also compared well with the results of other studies.
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Haghighi, Siavash, Mohammad Reza Kavianpour, and Keyvan Nasiri. "Experimental Study of Sand Sediments Effects on Submerged Hydraulic Jump Properties." Applied Mechanics and Materials 212-213 (October 2012): 366–71. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.366.
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Abstract. In this study, the effect of sediment concentration on submerged hydraulic jump (SHJ) characteristics such as jump length, submerged depth on the gate and the energy dissipation is investigated. Experiments were carried out in a flume of 46 cm depth, 12 m length. The width of the flume changes from 10 cm (at the entrance) to 60 cm (at the exit). Sediment load and flow concentration have an influence on submerged hydraulic jump characteristics including submerged depth on the gate, jump length and relative energy dissipation. It is shown that at high Froude numbers increasing the suspended sediment concentration to 28.7 gr/l leads to a reduction in the submerged depth on the gate up to 6% and jump length up to 10%. Also, the energy dissipation of the submerged hydraulic jump increases by 4% and turbulence resulting from the jump leads to upright distribution of concentration at the end of the jump. Also in concentrations higher than 30 gr/l, flow is not able to carry the whole sediments and subsequently leads to their deposition in subcritical area and behind the sluice gate.
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Jesudhas, Vimaldoss, Vesselina Roussinova, Ram Balachandar, and Ron Barron. "Submerged Hydraulic Jump Study Using DES." Journal of Hydraulic Engineering 143, no. 3 (March 2017): 04016091. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001231.
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Habibzadeh, Alireza, Mark R. Loewen, and Nallamuthu Rajaratnam. "Turbulence measurements in submerged hydraulic jumps with baffle blocks." Canadian Journal of Civil Engineering 43, no. 6 (June 2016): 553–61. http://dx.doi.org/10.1139/cjce-2015-0480.
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Laboratory measurements of turbulence in submerged hydraulic jumps with blocks downstream of a sluice gate are presented. As observed previously two flow regimes were distinguished; the deflected surface jet (DSJ) and the reattaching wall jet (RWJ) regimes. In the DSJ regime considerable turbulent kinetic energy (TKE) was generated just downstream of the blocks and the rate of dissipation of TKE was found to be very high resulting in a rapid decay of TKE. In the RWJ flow regime the magnitude of both the TKE and the dissipation rate were considerably lower but because the TKE decayed more slowly higher levels of TKE persisted farther downstream. This study provides insights into the production and dissipation of turbulence in submerged flows and helps to explain why a submerged jump with blocks with a low submergence factor; i.e., the DSJ flow regime, is as effective as a free jump in dissipating energy.
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Foda, Ahmed S., Yehya E. Imam, Abd Allah S. Bazaraa, and Emad H. Imam. "Three-dimensional numerical study of submerged spatial hydraulic jumps." Journal of Hydrology and Hydromechanics 68, no. 3 (September 1, 2020): 211–22. http://dx.doi.org/10.2478/johh-2020-0021.
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AbstractA three-dimensional numerical model was applied to simulate submerged spatial hydraulic jumps (SSHJ) downstream of a symmetric vent that discharges into a wider channel. Simulations were carried out for different aspect ratios of the vent, expansion ratios of vent width to downstream channel width, tailwater depth, and inlet Froude number. Depending on these factors, simulations indicated the formation of steady asymmetric SSHJ, oscillatory asymmetric SSHJ, and steady symmetric SSHJ, consistent with results of previous experimental studies. The model reproduced observed depth downstream of vent, jump length, and velocity profiles along channel centerline for steady symmetric SSHJ. For oscillatory asymmetric SSHJ, simulated oscillation frequencies had Strouhal numbers that varied with expansion ratio and ranged between 0.003 and 0.015. With piers downstream of the vent, oscillatory SSHJ continued to exhibit jet deflections when pier length was relatively short ( ≲ 0.2 of jump length) but became steady asymmetric for longer piers.
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NASRABADI, Mohsen, Mohammad Hossein OMID, and Javad FARHOUDI. "Submerged hydraulic jump with sediment-laden flow." International Journal of Sediment Research 27, no. 1 (March 2012): 100–111. http://dx.doi.org/10.1016/s1001-6279(12)60019-5.
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Ghaderi, Amir, Mehdi Dasineh, Francesco Aristodemo, and Costanza Aricò. "Numerical Simulations of the Flow Field of a Submerged Hydraulic Jump over Triangular Macroroughnesses." Water 13, no. 5 (March 2, 2021): 674. http://dx.doi.org/10.3390/w13050674.
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The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns in the cavity region of a submerged hydraulic jump in the rough beds, especially in the case of triangular macroroughnesses, are not completely understood. The objective of this paper was to numerically investigate via the FLOW-3D model the effects of triangular macroroughnesses on the characteristics of submerged jump, including the longitudinal profile of streamlines, flow patterns in the cavity region, horizontal velocity profiles, streamwise velocity distribution, thickness of the inner layer, bed shear stress coefficient, Turbulent Kinetic Energy (TKE) and energy loss, in different macroroughness arrangements and various inlet Froude numbers (1.7 < Fr1 < 9.3). To verify the accuracy and reliability of the present numerical simulations, literature experimental data were considered.
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Raiford, John P., and Abdul A. Khan. "Turbulence schemes for modelling a submerged hydraulic jump." Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics 166, no. 1 (March 2013): 40–51. http://dx.doi.org/10.1680/eacm.11.00003.
Full textDissertations / Theses on the topic "Submerged jump"
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McGhin, Ronald Francis. "Submerged Jump Remediation at Low-Head Dams: The Multiple Staggered Deflector Design." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6110.
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Low-head dams are capable of creating dangerous counter-currents just downstream from the structure. These dangerous counter-currents are known as submerged hydraulic jumps and are responsible for hundreds of fatalities at numerous low-head dams across the United States. The counter-current creates high upstream-directed surface velocities across the width of the channel, making it nearly impossible for an individual to escape. This submerged jump can occur during a range of upstream and downstream conditions. Effective, safe and low-cost remediation options must be explored in order to prevent further fatalities at these structures. This document explores such a remediation option: the Multiple Staggered Deflector Design. This remediation option will disrupt uniform upstream-directed surface velocities across the channel within a submerged jump for nearly all downstream conditions that create a submerged jump for a range of upstream conditions. The dam modification is designed such that an individual will escape the submerged jump without severe injury or harm, while being relatively inexpensive and simple to install.
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Lopez, Egea Marta. "Experimental and Numerical Modelling of Submerged Hydraulic Jumps at Low-Head Dams." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32345.
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This study, which includes both experimental and numerical-modelling components, investigates the potentially dangerous conditions that can often occur when low-head dams (or weirs) are overtopped and ‘submerged’-type hydraulic jumps subsequently form downstream of them. The combination of high local turbulence levels, air entrainment, and strong surface currents associated with submerged jumps pose a significant risk to safety of boaters and swimmers. In this study, a wide range of flow regimes and different experimental conditions (i.e. crest length and downstream apron elevation) were considered. The experimental phase involved physical model testing to determine: (i) the hydraulic conditions that govern submerged jump formation, and (ii) the hydrodynamic characteristics of the submerged vortex. The numerical model, developed using OpenFOAM, was validated with the obtained experimental data. This research seeks to help develop improved guidelines for the design and safe operation of low-head dams. The experimental phase of the study involved physical model testing to
determine: (i) the hydraulic conditions that govern submerged jump formation, and (ii) the hydrodynamic characteristics of the submerged vortex. The numerical modelling work involved using interFoam (OpenFOAM toolbox) for simulating the experimental results. InterFoam is an Eulerian 3-D solver for multiphase incompressible fluids that employs the Volume of Fluid approach (VOF) to capture the water-air interface. The developed numerical model was subsequently validated using the experimental data collected and processed by the author of this study.
The range of tailwater depths associated with submerged hydraulic jump
formation is dramatically reduced when a broad-crested weir is coupled with an elevated downstream apron, especially under high flow rate conditions. However sharp-crested weirs induced vortices which displayed reduced velocities and decreased spatial development, which were judged to be safer than broad crest lengths under the same discharge conditions. The classical formulation for the degree of submergence was not explicative when used to evaluate “how submerged the vortex was”. Consequently, a new normalized formulation which compares the local tailwater depth to the lower and upper tailwater limits for the submerged hydraulic jump is proposed. The numerical model developed for this study demonstrated the existence of residual turbulent kinetic energy at downstream sections located within the vortex’s extension, at instants coinciding with the presence of a fully formed roller. This turbulent energy is arguably responsible for the stationary nature of the vortex under constant flow conditions. Residual vertical and horizontal velocities at points located within the vortex’s domain are indicative of the existence of the free surface current.
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Lin, Yanping. "Improvement of HAZ in multi-pass NG submerged arc welding." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39376.
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The study emphasizes the effects of multi-pass narrow gap (NG) Submerged-Arc welding (SAW) on the Heat Affected Zone (HAZ). The differences between the HAZ of single-pass welds and multi-pass welds are radical and are caused by the subsequent thermal cycles which only exist in multi-pass welding.A series of experiments were carried out to establish the relationship between the welding thermal cycles and the mechanical and microstructural properties of a HAZ. Both real and Gleeble simulated HAZ's were investigated.
Theoretical and experimental analyses indicate that the HAZ's in multi-pass welds can be improved significantly by the welding process itself. However, multi-pass welding does not always improve its HAZ. To realize the improvement, some special criteria must be met. The most important parameters are heat input, welding speed, deposit thickness and inter-pass temperature. This study establishes the relations between these parameters and the effects of HAZ refinement. There are some domains of the parameters in which HAZ refinement can be realized. The research reveals that in multi-pass NG welding, a set of welding parameters can always be found to fulfill the conditions for HAZ improvement.
Real welding processes, with welding parameters optimized according to the analyses, were performed and a totally refined HAZ was achieved under laboratory conditions. It is suggested that the method can be applied to in situ welding situations.
High heat input does not necessarily lead to inferior microstructural and mechanical properties in multi-pass NG welding. As long as the conditions for HAZ refinement are satisfied, an improved HAZ will be obtained no matter how high the heat input is. This also leads to the conclusion that the HAZ in multi-pass NG welding is less sensitive to heat input than that in single pass welding.
The tempering parameter, which has been used to evaluate the tempering effects at constant temperature, is successfully introduced into welding (non-isothermal) conditions. The effects of precipitates in 2.25Cr-1Mo steel are theoretically investigated.
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Rooney, Neil. "Scale of analysis and the influence of submerged macrophytes on lake processes." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37665.
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The goal of this thesis was to examine submerged macrophoe biomass, distribution, and ecosystem effects at scales large enough to incorporate the littoral zone into models of whole lake structure and function. Submerged macrophyte biomass and distribution was shown to be highly variable between growing seasons and primarily dependant upon air temperature and the timing of the onset of the growing season. Within a growing season, a mass balance study showed an undisturbed macrophyte bed to markedly lower phytoplankton biomass: total phosphorus ratios, although the net effect of the bed on the growing season phosphorus budget was minimal. The weedbed preferentially retained phytoplankton biomass while being a source of bacterial production to the open water. These findings were mirrored at the among lake scale, as planktonic respiration and bacterial production were higher in macrophyte dominated lakes than would be expected based on phytoplankton biomass alone. Further, phytoplankton biomass was lower than would be expected based on epilimnetic phosphorus levels, showing that the classical view of pelagic interactions that proposes phosphorus determines phytoplankton abundance, which in turn determines bacterial abundance through the production of organic carbon, becomes less relevant as macrophyte cover increases. Long term phosphorus accumulation in the littoral zone was shown to be linked to macrophyte biomass, and on average almost an order of magnitude higher than calculated from the growing season (June--October) phosphorus budget, suggesting that the bulk of phosphorus accumulation in weedbeds occurs outside of the growing season. Finally, sediment core data showed that while submerged weedbeds accumulate up to four times as much bulk sediment compared to the profundal zone, phosphorus accumulation in weedbeds is much less than observed in the profundal zone. These results strongly indicating that submerged macrophyte beds play a central role in trapping ep
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Bérubé, Esther. "The production of phenol oxidases by white-rot fungi in submerged liquid culture /." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79999.
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Three species of white-rot fungi, Phlebia radiata, Phanerochaete chrysosporium, and Trametes versicolor, were monitored for laccase and lignin peroxidase production in a defined medium. P. radiata was selected for fed-batch reactor experiments due to its early laccase production, which was determined to be growth-associated. A second peak in laccase activity was observed after several days of nutrient deprivation and was attributed to autolysis of the culture. The effect of protease activity on the accumulation of extracellular laccase activity differed during primary and secondary metabolism, as observed under various conditions of nitrogen and glucose availability. A mixed culture of P. radiata and P. chrysosporium was grown on ammonium lignosulfonate, a by-product of the pulp and paper industry, as sole source of carbon and nitrogen. Under these conditions, laccase production appeared to exceed laccase production by P. radiata in defined culture medium.
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Wan, Mohtar Wan Abd A. Q. I. "Production and bioactivity of Ganoderma lucidum BCCM 31549 exopolysaccharide using submerged liquid fermentation." Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26556.
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The RBF strategy has successfully produced fungal mycelial biomass and EPS in a very strictly regulated manner at high productivity rates compared to batch fermentation. The problematic lag phase and seed culture preparation were reduced in length; harvesting volume doubled, yield of product increased, and medium consumption was reduced in an RBF relative to batch. 80% broth replacement volume and transition phase were optimised. Dispersed mycelial filaments with ovoid-shaped pellets are the typical morphological characteristics associated with EPS production. N-limiting medium in an unbaffled 2.5-L bioreactor stimulated EPS formation during RBF compared to in baffled condition. The current study has managed to alter the molecule's hydrophobicity thus making it water-soluble as proved by compositional analysis and spectroscopy. The sulphated derivative of native glucan was identified as (1, 3)-(Sb(B-D-glucan. Sulphation was an effective approach to improve antibacterial, antifungal, antiproliferative and immunomodulatory (NO stimulation) activity of the sulphated (1,3)-(Sb(B-D-glucan or GS. GS maybe safe in in vitro trials due to its demonstrated lack of toxicity towards a normal human prostate cell line (PN2TA). GS also showed antimicrobial-antifungal-immunomodulatory activities derived from a single compound. Fungal cells tended to grow well in the porous structure of PUF cubes and the RBF using immobilised fungal cells was an efficient method for production of (Sb(B-glucan with a high yield. This study could be beneficial for other medicinal mushroom fermentation.
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Yamanoglu, Güller. "Characterisation of submerged powder injection into water using an in-line particle detection system." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69586.
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Particle behaviour during the downwards, pneumatic injection of powder into an aqueous medium (water) has been investigated by means of a new method which involves direct measurement by making use of an Aqueous Particle Sensor (APS) unit. Through this method, phenomena and parameters related to injection processes, such as gas-particle jet penetration distance, jet diameter, jet cone angle, particle dispersion and distribution within the liquid have been investigated both qualitatively and quantitatively. Flow observations comprised part of the experimental program for the purpose of confirming the characteristics of the "gas-only" and "gas-powder" injection regimes reported by previous workers.The effect of gas and powder flow rates (powder/gas loading ratio) in determining the injection regimes and particle behaviour within the liquid were the main parameters investigated.
It was demonstrated that the jetting regime can be easily achieved as a result of increased momentum transfer from the particles to the gas phase. However, this required a high loading of particles. Entrainment of gas with the injected particles took place not only during coupled flow (jetting) but also during decoupled (bubbling) flow, such that some gas was always entrained by the particles and penetrated the liquid as a gas-particle jet, leaving large gas bubbles at the lance tip. It was further demonstrated that the gas flow rate had a greater effect on particle suspension within the liquid than did the powder flow rate.
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Rodrigue-Gervais, Karen 1981. "Investigation of temporal scour development and flow dynamics around submerged deflectors in a laboratory flume." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116074.
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Although flow deflectors are routinely placed in streams to create fish pool habitat, there is dissent in the literature as to what constitutes for them an appropriate design height to ensure their success. Our objectives were to (1) examine the temporal evolution of bed topography around submerged deflectors in a laboratory flume, for different deflector heights and discharge; and (2) quantify the flow dynamics in their vicinity. Results indicate that, all else being equal, higher deflectors (characterized by less overtopping) produce a greater volume of fish pools. In contrast, over a fixed deflector design, a higher discharge (synonymous with greater overtopping) results in larger pools, because flow velocities are then faster. We also observed differences in the temporal behaviour of scour: that next to high and medium height deflectors is self-similar, but not that for the shorter model. Our results challenge the notion that low deflectors are ineffective, provide information on the development of scour next to submerged structures, and reveal key differences between the geometry of the scour holes engendered by the different deflector height models.
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Ramalho, Jorge Filipe Pedras. "Determinação de caudais em comportas para diferentes situações de escoamento." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/18298.
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A vazão em comportas planas verticais foi determinada através de vários métodos de cálculo, sendo alguns calibrados com medições realizadas em canal laboratorial. As equações testadas baseiam-se nos métodos da energia-quantidade de movimento, algumas considerando um fator de correção, e no teorema dos da análise dimensional. O estudo foi desenvolvido para as situações de ressalto hidráulico livre e submerso. Entre todas as formulações consideradas, obteve-se um erro médio geral para escoamento com ressalto livre de 4% e com ressalto submerso de 9%. Para ressalto livre, o método mais preciso gerou erros próximos de 2% e, para ressalto submerso, o método mais preciso obteve um erro médio de 4%. Foram também comparadas algumas equações de fronteira, entre o ressalto livre e submerso, tendo-se concluído que uma das equações garante maior rigor na definição dessa fronteira; ABSTRACT: Discharge in vertical sluice gates was computed by different calculation methods, some of them calibrated with measurements performed in a laboratory canal. The tested equations are based in energy-momentum method, some of them consider a correction factor, and in a method based on -theorem of the dimensional analysis. The study was developed for free and submerged flow. From all the equations considered, there were obtained an overall average error for free flow of 4% and for submerged flow of 9%. In free flow, the most accurate method obtained an error close to 2% and in submerged flow, the most accurate method an error of 4%. Were also compared some equations of distinguishing condition, which function is determine the type of hydraulic jump. One of the considered equations gave the best result and accuracy in the definition of the frontier between free and submerged flow.
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Jambi, Ebtihaj J. "Comparative studies on the cultivation of Xanthomonas campestris in submerged culture for the production of xanthan using the traditional industrial stirred tank reactor and a novel oscillatory baffled bioreactor." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18713.
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Xanthan is a well-known extracellular polysaccharide, produced by a Gram negative bacterium Xanthomonas campestris (X. campestris) under aerobic conditions. Solutions of xanthan exhibit high viscosities and non-Newtonian behaviour even at low concentrations. This biopolymer has a wide range of valuable commercial and industrial applications, for example; it can be used as a food thickening agent and a stabilizer in some other industries. Traditionally the production of xanthan has predominantly been performed in stirred tank fermenter (STR). This study sought to compare the cultivation of the bacterium, X. campestris for the production of the viscous biopolymer xanthan gum in two different reactor systems, a novel oscillatory baffled reactor (OBR) and the conventional industry workhorse, the stirred tank reactor (STR). Overall biopolymer production occurred at similar rates in the well stirred and aerated STRs, albeit at the cost of higher energy inputs for mixing and aeration. Despite much previous literature promoting the use of the OBR for transporting and reacting very viscous systems, this was the first actual study attempting to investigate the use of the OBR for a highly viscous non-Newtonian fermentation process. The experimental results show that xanthan production was similar in the OBR than in the STR, the OBR is however readily suitable for the cultivation of xanthan. The probable reasons for the inability of the OBR to match the production rates of the STR may well lie in the complex nature of this fermentation process. Unlike a previous study on pullulan production (Gaidhani 2004) where the OBR outperformed the STR, X. campestris initially needs high oxygen transfer rates and the OBR, although it provides good bulk mixing and low energy consumption, seemed unable to equal the STR in this respect, especially in a very viscous system. The result shows that xanthan production in the OBR was similar to the equivalent process in the STR. In order to attempt to improve the OBR a number of technical modifications were made including a novel sparger design to improve gas dispersal. These were not successful in improving xanthan production. Similarly, attempts to achieve improvements via wider amplitude ranges led to damage to the equipment. The conclusion was that significant improvements to the physical robustness of the OBR were necessary before it could be successfully used to process highly viscous bio-fluids.
Books on the topic "Submerged jump"
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Fan, Jerry Jie. Submerged hydraulic jumps at overflow structures. Ottawa: National Library of Canada, 1993.
Find full textBook chapters on the topic "Submerged jump"
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Hager, Willi H. "Submerged Jumps." In Energy Dissipators and Hydraulic Jump, 67–76. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-015-8048-9_5.
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Huichao, Dai, and Wang Lingling. "Numerical study of submerged hydraulic jump." In Environmental Hydraulics and Sustainable Water Management, Two Volume Set, 1697–702. CRC Press, 2004. http://dx.doi.org/10.1201/b16814-277.
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Lopardo, R., C. Fattor, M. Lopardo, and J. Casado. "Instantaneous pressure field on a submerged jump stilling basin." In Hydraulics of Dams and River Structures, 133–38. CRC Press, 2004. http://dx.doi.org/10.1201/b16994-19.
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"Biology, Management, and Conservation of Lampreys in North America." In Biology, Management, and Conservation of Lampreys in North America, edited by Ulrich G. Reinhardt, Thomas Binder, and D. Gordon McDonald. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874134.ch6.
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<em>Abstract</em>.—Low-head barriers against invasive sea lampreys <em>Petromyzon marinus</em> in the Great Lakes are designed to maintain a minimum crest height of 30 cm and have a lip on the crest to prevent them from climbing over the barrier. We tested the ability of migratory-phase sea lampreys to scale inclined ramps with shallow (0.7–5 cm) water depth. We predicted that sea lampreys would jump the barrier and that their ability to attach would increase passage success. A recirculating flume and ramp with a vertical height of 10–30 cm and an inclination between 308 and 608 were used to evaluate lamprey climbing ability. Lampreys trying to scale the ramp were monitored by passive integrated transponder tag readers and low-light video cameras. No lampreys were observed jumping out of the water to scale a barrier. Independent of ramp angle, no fish passed over a 30-cm ramp. Lampreys often attached themselves to the ramp, but without a gain of vertical height between repeated attempts. The success rate at lower ramp heights varied between 0% (15 cm height, 308 angle) and 63% (10 cm height, 608 angle). Only ramps shorter than half the body length of the lampreys could be surmounted. Apparently, the lampreys had to have their dorso-ventral fins fully submerged in the downstream pool to create enough propulsion to scale a ramp in burst-swimming mode. An analysis of 1,300 passage attempts in a field-validation experiment showed a greater apparent motivation to move up a ramp but reconfirmed our laboratory findings on passage technique and maximum performance. We conclude that sea lamprey barrier height could be further reduced and that an overhanging lip is not necessary as sea lampreys neither climb nor jump over barriers. A ramp with a shallow inclination and moderate vertical height and water flow is a new design suggestion for a barrier that blocks sea lampreys and may allow other fish species to pass.
Conference papers on the topic "Submerged jump"
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SMOK, SOCHHEAT, and ENDER DEMIREL. "PRESSURE MEASUREMENTS ON THE GATE SUBJECTED TO SUBMERGED HYDRAULIC JUMP." In AFM18. Southampton UK: WIT Press, 2018. http://dx.doi.org/10.2495/afm180291.
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Mehdizadeh, A., B. Firoozabadi, and S. A. Sherif. "Numerical Simulation of Submerged Flows With Baffles Using v2-f- and k-e Turbulence Models." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14304.
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This paper introduces the concept of a submerged hydraulic jump being used for energy dissipation. A baffle wall is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model ([Equation] - f model) has been used to simulate this submerged flow. During the last few years, the [Equation] - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the [Equation] - f model is superior to other RANS methods in many fluid flows where complex flow features are present. In this study, we compared the results of both models with each other and with available experimental data. In addition, based on a series of numerical simulations, a diagram was developed that predicts the effect of baffle position on the friction coefficient over the bed. This feature should help preventing or reducing erosion over the bed. Moreover, we have shown that in numerical simulation, like experimental data, in some cases the flow regimes of submerged flow with baffles can either be a deflected surface jet or reattached wall jet.
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Raiford, John P., and Abdul A. Khan. "Numerical Modeling of Internal Flow Structure in Submerged Hydraulic Jumps." In World Environmental and Water Resources Congress 2006. Reston, VA: American Society of Civil Engineers, 2006. http://dx.doi.org/10.1061/40856(200)49.
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ISHIKAWA, MOTOYASU, MASAYUKI TAKAHASHI, and IWAO OHTSU. "New Expression for the Length of Free, Submerged, and B- Jumps." In 38th IAHR World Congress. The International Association for Hydro-Environment Engineering and Research (IAHR), 2019. http://dx.doi.org/10.3850/38wc092019-1392.
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Amabili, Marco, Prabakaran Balasubramanian, Giovanni Ferrari, Giulio M. Franchini, Francesco Giovanniello, Kostas Karazis, and Brian Painter. "Experiments on Nonlinear Vibrations of a Nuclear Fuel Rod Supported by Spacer Grids in Air and Submerged in Water." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10663.
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Abstract For safety reasons, the nuclear fuel assemblies of Pressurized Water Reactors (PWR) must be able to withstand external excitations ranging from large amplitude seismic motions of the reactor to flow-induced vibrations from the surrounding coolant water. A nuclear fuel assembly is composed of long slender tubes, most of them filled with uranium pellets, maintained in a square array by spacer grids. The spacer grids provide a nonlinear flexible boundary condition with friction and micro-impacts that complicates the nonlinear dynamics. In order to improve safety margins in the design of nuclear fuel assemblies, it is of great interest to understand the influence of the spacer grids, as it relates to the overall structural stiffness and damping properties. In particular, the evolution of the vibration amplitude with increasing excitation forces is still undetermined. In order to understand the nonlinear vibration response of a zirconium fuel rod filled with nuclear fuel pellets and supported by spacer grids, experiments were carried out in water and in air. They consisted of measuring the vibration response of the rod under a step-sine harmonic excitation at different force amplitude levels in the frequency neighborhood of the fundamental mode. If the excitation is large enough, the response of the rod displays nonlinear phenomena such as the shift of the resonant frequencies, multiple solutions with instabilities (jumps) and hysteresis, and one-to-one internal resonances. These experiments were carried out on zirconium tubes filled with axially unconstrained as well as axially blocked metallic pellets, which simulate the nuclear fuel. The zirconium tubes were tested both in air and immersed in water. The experimental data will be processed in the future by means of an identification procedure to extract the nonlinear stiffness and damping parameters of the system. An increase of the equivalent viscous damping with the excitation amplitude level is expected.