Rozprawy doktorskie: „Channels (Hydraulic engineering)”

1

Davis, Gary Stanley. "A laboratory investigation of a rock riprap control structure in an open channel". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/21006.

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Dickman, Brian Daniel. "Large scale roughness in open channel flow". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/22953.

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3

Shumate, Eric Dean. "Experimental Description of Flow at an Open-Channel Junction". Thesis, University of Iowa, 1998. https://ir.uiowa.edu/etd/5368.

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4

Papadopoulou, Symela. "Velocity distribution in shallow open channel flow over square bar roughness". Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=58994.

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5

Ebisa, Fola Miressa. "Downstream hydraulic geometry of clay-dominated cohesive bed stream channels". Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27838.

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Empirical downstream hydraulic geometry equations for clay-dominated cohesive bed (semi-alluvial) streams were derived using the data from five streams in eastern Ontario and four streams from other regions. The width exponent (0.57) is comparable to the exponents reported for previous studies; however, depth exponent (0.52) was greater for clay-dominated cohesive bed than for typical gravel-bed and sand-bed rivers. Furthermore, the recurrence intervals of bankfull discharges of those streams range from 1 to 2 years. To the author's knowledge, this is the first study which related bankfull hydraulic variables and discharges to derive downstream hydraulic geometry equations specifically for clay-dominated cohesive bed streams. Assessment of width:depth ratio depicted that large channels were deeper and narrower than comparable gravel-bed channels, but small channels were actually wider and shallower than typical gravel-bed rivers. This can likely be attributed to the resistance of stiff and consolidated cohesive-bed to erosive effects of more frequent flows.

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6

Hardwick, Richard Ian. "The behaviour of meandering channels in flood". Thesis, University of Aberdeen, 1992. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=192102.

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This study had three primary aims. Firstly, to establish the flow resistance characteristics of meandering channels in flood with different inner channel sinuosities and morphology. Secondly, to gain a better understanding of the coherent flow structures and energy loss mechanisms present within such flows. Third, to establish a link between the identified energy loss mechanisms and the flow resistance behaviour of channels with different geometry. The study begins with a review of current literature appertaining to three flow systems. These were; Inbank flow through meandering channels, overbank flow through channels comprising a straight channel with straight parallel floodplains, and meandering channels with floodplain flow. The available literature with regards to flooded meandering channels was limited to a handful of studies. It was clear there existed a deficiency in stage-discharge data over a range of inner channel sinuosities, and the flow descriptions given were limited to inner channels of relatively low sinuosity i.e. 1.25 - 1.3, rectangular or trapezoidal cross-section and unrealistically low width to depth (aspect) ratio. In addition, the influence of roughened floodplains also required further study. To address these needs, a small-scale laboratory investigation was undertaken at Aberdeen, together with a large-scale collaborative experimental study centred at the SERC Flood Channel Facility. These two experimental studies, in which two inner channels of sinuosity 1.4 and 2 were investigated in detail, are described. The experimental techniques and data collection procedures used are also described. The data types collected include: stage- discharge data, flow visualisation, flow velocity measurement, water surface profiles and bed shear stress analysis using an erodible bed. The stage-discharge data were used for the following; to establish the relationship between inner channel sinuosity and overall channel flow resistance; to establish the effect of inner channel morphology on overall channel resistance: and to assess the implications of roughened floodplains on resistance behaviour. The analysis of these data, together with existing related overbank data, yielded a number of conclusions; i). Overall flow resistance increases as inner channel sinuosity increases, ii). At deep floodplain flows, a floodplain comprising a trapezoidal inner channel was less efficient than one comprising a smaller natural inner channel, iii). Roughening the floodplains has a significant effect on channel resistance characteristics. The flow description data, of overbank flow, revealed the presence of coherent flow structures in flows over inner channels of sinuosity 1.4 and 2, and at a number of flow depths. It is suggested these coherent flow structures are a source of additional energy loss, and a link is proposed between the vigour and frequency of these structures for several flow conditions and channel geometries, and the overall resistance behaviour. Contour maps of water surface elevation are presented for several flow conditions and channel geometries. An increase in surface relief was observed as floodplain depth, and therefore velocity, increased. These maps and earlier related work were then discussed. Plots of near bed velocities, secondary circulation patterns and erodible bed observations strongly indicated a change in sediment erosion and deposition patterns, and thus a change in inner channel morphology during overbank flow. Implications of this change are proposed and discussed. Finally, suggestions for future work are presented. with particular emphasis on a 3-dimensional numerical model presently under development at the University of Aberdeen.

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7

Cabral, Mariza Castanheira de Moura da Costa. "Effects of spatial constraints on channel network topology : implications for geomorphological inference /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10147.

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8

Shea, Charles Brian. "Optimal well location in contaminant plume remediation". Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/19465.

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9

Ratzlaff, Steven Abraham. "Optimal well location in contaminant plume containment". Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/20017.

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10

Sadiq, Aftab. "Clear-water scour around bridge abutments in compound channels". Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/19308.

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11

Cloete, Gert Christiaan. "River discharges derived from single velocity measurements". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50087.

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Thesis (MScEng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: This work investigates methods to theoretically determine the lateral velocity distribution across a river from which factors may be derived to translate a single point velocity into average velocity for the river as a whole. A wide range of field data from vanous nvers was analysed. This produced over a hundred velocity distributions with which to compare theoretical distribution results. Four theoretical approaches were considered: the one-dimensional method (Manning's equation), a two-dimensional flow formula solved as an initial-value-problem, a two dimensional flow formula solved as a boundary-value-problem and an empirical method developed from energy principles. The one-dimensional and initial-value-problem approaches were unsuccessful. The boundary-value and empirical approach did however produce promising results. Surprisingly the analysis of the field data revealed patterns of similarity which could produce accurate results without the need of a theoretical approach.
AFRIKAANSE OPSOMMING: Metodes word ondersoek om teoreties 'n laterale snelheidsverspreiding oor 'n rivier te bepaal en sodoende 'n faktor te vind waarmee 'n gemete enkelpuntsnelheid in die rivier omgeskakel kan word na 'n gemiddelde snelheid vir die rivier in geheel. Vloeimeetdata van verskeie nviere IS geanaliseer. Sodoende is meer as 100 snelheidsverspreidings gegenereer waarmee die teorie vergelyk kon word. Vier teoretiese benaderings is gevolg: Manning se een-dimensionele vloeivergelyking, 'n twee dimensionele vloei-vergelyking opgelos met behulp van 'n beginwaarde, 'n twee dimensionele vloei-vergelyking opgelos met behulp van randwaardes, en 'n empiriese metode ontwikkel vanuit energie beginsels. Die een-dimensionele- en beginwaarde-benaderings was me suksesvol me. Die randwaarde- en empiriese benaderings het wel belowende resultate gelewer. Selfs verwerking van die gemete stroommetings het waardevolle inligting gelewer: daar bestaan duidelike ooreenkomste in die snelheidsverspreidings wat gebruik kan word om die verspreidingsfaktor mee te bereken sonder om teoretiese oplossings te soek.

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12

Mulahasan, Saad. "Hydrodynamics of large-scale roughness in open channels". Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/95099/.

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This thesis investigates the hydrodynamics of flow around/and or above an obstacle(s) placed in a fully turbulent developed flow such as flow around lateral bridge constriction, flow over bridge deck and flow over square ribs that are characterized with free surface flow. Also this thesis examines the flow around one-line circular cylinders placed at centre in a single open channel and floodplain edge in a compound, open channel. *Hydrodynamics studies of compound channels with vegetated floodplain have been carried out by a number studies of authors in the last three decades. To enrich our understanding of the flow resistance, comprehensive experiments are carried out with two vegetation configurations-wholly vegetated floodplain and one-line vegetation and then compared to smooth unvegetated compound channel. The main result of the flow characteristics in vegetated compound channels is that spanwise velocity profiles exhibit markedly different characters in the one-line and wholly-vegetated configurations. Moreover, flow resistance estimation results are in agreement with other experimental studies. *A complementary experimental study was carried out to investigate the water surface response in an open-channel flow through a lateral channel constriction and a bridge opening with overtopping. The flow through the bridge openings is characterized by very strong variation of the water surface including undular hydraulic jumps. The results of simulation that was carried by (Kara et al. 2014, 2015) showed a reasonable agreement between measured and computed water surface profiles for the constriction case and a fairly good was achieved for the overtopping case. *Evaluation of the shear layer dynamics in compound channel flows is carried out using infrared thermography technique with two vegetation configurations - wholly vegetated floodplain and one-line vegetation in comparison to non-vegetated floodplains. This technique also manifests some potential as a flow visualization technique, and leaves space for future studies and research. Results highlight that the mixing shear layer at the interface between the main channel and the floodplain is well captured and quantified by this novel approach. iii *Flume experiments of turbulent open channel flows over bed-mounted square bars at low and intermediate submergence are carried out for six cases. Two bar spacings, corresponding to transitional and k-type roughness, and three flow rates, are investigated. This experimental study focused on two of the most aspects of channel rough shallow flows: water surface profile and mean streamwise vertical velocity. Results show that the water surface was observed to be very complex and turbulent for the large spacing cases, and comprised a single hydraulic jump between the bars. The streamwise position of the jump varied between the cases, with the distance of the jump from the previous upstream bar increasing with flow rate. The free surface was observed to be less complex in the small spacing cases, particularly for the two higher flow rates, in which case the flow resembled a classic skimming flow. The Darcy-Weisbach friction factor was calculated for all six cases from a simple momentum balance, and it was shown that for a given flow rate the larger bar spacing produces higher resistance. The result of the simulation that was carried out by Chua et al. (2016) shows good agreement with the experiments in terms of mean free surface position and mean streamwise velocity. *Drag coefficient empirical equations are predicted by a number of authors for an array of vegetation. The research aims to assess the suitability of various empirical formulations to predict the drag coefficient of in-line vegetation. Drag coefficient results show that varying the diameter of the rigid emergent vegetation affects significantly flow resistance. Good agreement is generally observed with those empirical equations. Key Words: Flow Visualization; Infrared Thermography; Shallow Flows; Shear layer; Image processing; Experiment; Free surface; Bridge hydrodynamics; Bridge overtopping; Vegetation roughness, Emergent vegetation, Drag coefficient, blockage; Compound channel, Lateral velocity profiles; Hydraulic resistance; Hydraulic jump, Square bars.

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13

O'Sullivan, John. "The hydraulic performance of meandering mobile bed compound channels with uniform sediment". Thesis, University of Ulster, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310109.

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14

Coffman, David K. Allen Peter M. "Streambank erosion assessment in non-cohesive channels using erosion pins and submerged jet testing, Dallas/Fort Worth, Texas". Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5318.

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15

Chlebek, Jennifer. "Modelling of simple prismatic channels with varying roughness using the SKM and a study of flows in smooth non-prismatic channels with skewed floodplains". Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/688/.

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Accurate modelling, both numerical and physical, is vital to further our understanding of flow in rivers. This thesis examines both methods of flow applied to two distinct problems; numerical modelling of flow in simple channels with heterogeneous roughness and physical modelling of flow in compound channels with skewed floodplains. In this thesis, the Shiono and Knight Method (SKM) is applied to homogeneously and heterogeneously roughened channels. The SKM is shown to be capable of accurately predicting the lateral distributions of depth-averaged velocity and boundary shear stress for both roughness types. Furthermore, the percentage shear force on the wall of a channel is accurately obtained for both roughness types and guidance is given as to the choice of the three calibration coefficients the model requires, namely f, l and G representing friction, eddy viscosity and secondary flow respectively. Finally, physical modelling has been undertaken on compound channels with skewed floodplains in addition to a full review of the work undertaken at a larger scale in the Flood Channel Facility. As a result appropriate expressions for shear force and apparent shear forces acting on the horizontal and vertical interfaces have been established.

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16

Thein, Myint. "Experimental investigation of flow resistance and velocity distributions in a rectangular channel with large bed-roughness elements". Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/19580.

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17

Lu, Zhihua. "Stochastic modelling of unsteady open channel flow and reliability analysis /". View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202008%20LU.

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18

Friedrichs, Carl T. "Hydrodynamics and morphodynamics of shallow tidal channels and intertidal flates /". Woods Hole, Mass. : Woods Hole Oceanographic Institution, 1993. http://hdl.handle.net/1912/1176.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, 1993.
"Doctoral dissertation." "February 1993." At head of title: Woods Hole Oceanographic Institution, Massachusetts Institute of Technology. Includes bibliographical references (p. 205-214).

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19

Restivo, Anthony Paul. "High speed videotape investigation of inclined open channel granular material flows". Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/19171.

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20

Marjang, Nat. "Calculated Surface Velocity Coeffiecients for Prismatic Open Channels by Three-Dimensional Hydraulic Modeling". DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/64.

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A turbulence model was developed for computing surface velocity coefficients and discharge under steady, uniform flow conditions for rectangular and compound open-channel cross sections. Reynolds-Average Navier-Stokes (RANS) equations, Reynolds stress equations, and kinetic energy and dissipation equations were applied in the model using the finite-volume method with the SIMPLER algorithm. The models show graphical results of the velocity distributions in the longitudinal bed slope direction, secondary velocities, pressure, turbulence kinetic energy, and kinetic energy dissipation rate across the cross section. Also, the surface velocity coefficients were computed at increments of one-eighth of the base width from the vertical walls to the center of the cross section, and the submergence depth of the floating object from zero to 30 cm, with a 5-cm depth increment. Four different sets of Reynolds stress equations (one set by Boussinesq hypothesis and three sets of algebraic stress model) were used to calculate the results. Only one version of the algebraic stress model was successful in predicting the depression of the maximum streamwise velocity below the water surface. The model was calibrated and verified using laboratory data collected at Utah State University. Calculated discharges from the turbulence model had very good agreement with the laboratory data. The surface velocity coefficients from model results were generally lower than the results from the laboratory data, but higher than the values published by the United States Bureau of Reclamation. Standard cross sections of rectangular and compound cross sections were defined to simulate the model results and model sensitivity to parameter changes. The model results were summarized to show the relationship between surface velocity coefficient and channel characteristics compared with the published values by the USBR. For rectangular cross sections, the coefficients from the model are higher than the published USBR values. But the coefficients from the model and USBR are in very close agreement for the tested compound cross sections. The published coefficients by the USBR are a function of only average water depth. However, the model results show that the coefficients are also related to channel size, surface roughness height, float submergence depth, and lateral location of the float object. These factors should be included in the determination of the surface velocity coefficient to improve the discharge estimations from the application of the float method.

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21

Stoffberg, Francis Wilhelm. "Evaluation of incipient motion criteria for rock in Reno mattresses and rip rap /". Link to the online version, 2005. http://hdl.handle.net/10019/1224.

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22

Zhang, Yi. "Numerical modeling of shock wave propagation and contaminant fate and transport in open channel networks". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/20159.

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23

ALAWI, ADNAN JASSIM. "SOME CONTRIBUTIONS TO THE STUDY OF SCOUR IN LONG CONTRACTIONS (EQUIVALENT, SECTION, SEDIMENTATION)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187967.

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The first objective of this investigation was to derive and compare scour depth equations in a long contraction using the most widely used sediment transport equations and a variety of other equations. The second objective was to determine a procedure to find an equivalent rectangular section which would convey the same water discharge and sediment load at same slope as an irregular, natural channel in order to simplify numerical computations of scour depth and to allow appropriate application of long contraction scour theory. Some of the transport equations were manipulated algebraically to develop equations for scour depth and slope in a long contraction; others were manipulated using computer programs written especially for each equation, thus deriving scour depth equations. A computer program was written to compare characteristics of a non-rectangular section with rectangular sections of different widths in order to derive a procedure to find an equivalent rectangular transport section (a triangular section was used in this investigation) but the procedure is equally valid for any irregular, natural section. This investigation indicated that depth in the contraction is greater than in the wider approach channel. How much greater depended on which sediment-transport equation was used. Most of the derived scour equations, based on the different sediment transport equations, predicted that the y₂/y₁ ratio decreases as slope, velocity, c, and τₒ'/τ(c) or √τ/ρ)/ω increase; a few do not. Most of the analysis predicted S₂ < S₁, but a few do not. Field and experimental data provided extra evidence that the depth in the contracted section is greater than in the approach reach and how much greater. The evidence that the slope is flatter is not sufficient to be completely convincing. The equivalent rectangular transport section which can carry the same water and sediment discharge at the same slope as the natural section has a depth which is a large fraction of the deepest part of the original section, and the width is considerably narrower than the top width of the original section. Results of the investigation also indicated that the slope, velocity, sediment concentration, and sediment size have little effect on the geometry of the equivalent rectangular section.

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24

Ying, Ker-Jen. "Lift on a sphere in shear flow near flat channel bed". Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39966.

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25

Wells, Jared Lawrence. "Effect of angular orientation on the hydrodynamic forces acting on a body in a restricted waterway". Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/41572.

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A slender body theory method developed for a body moving parallel to a wall in shallow water is extended to include angular orientation of the body to the wall. The method satisfies only the zero normal velocity condition on the external boundaries but does not take into account the effect of induced flows on the body itself. A spheroid and a Series 60, block .80 hull were the bodies studied. The side force and yaw moment on each body were determined numerically for varying angular orientation with respect to either a single wall or canal bank. For both cases results for a range of depths and wall separation distances are presented. It is found that the method gives good qualitative side force predictions for a body moving parallel to a wall, but is unable to correctly predict the yaw moment or the side force due to angular orientation. This result dictates the need for a more complex mathematical model to properly represent the flow than the simple model and quasiâ steady method used here.

Master of Science

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26

Ozturk, Hayrullah Ugras. "Discharge Predictions Using Ann In Sloping Rectangular Channels With Free Overfall". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606706/index.pdf.

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In recent years, artificial neural networks (ANNs) have been applied to estimate in many areas of hydrology and hydraulic engineering. In this thesis, multilayered feedforward backpropagation algorithm was used to establish for the prediction of unit discharge q (m3/s/m) in a rectangular free overfall. Researchers&rsquo
experimental data were used to train and validate the network with high reliability. First, an appropriate ANN model has been established by considering determination of hidden layer and node numbers related to training function and training epoch number. Then by applying sensitivity analysis, parameters involved in and their effectiveness relatively has been determined in the phenomenon. In the scope of the thesis, there are two case studies. In the first case study, ANN models reliability has been investigated according to the training data clustered and the results are given by comparing to regression analysis. In the second case, ANN models&rsquo
ability in establishing relations with different data clusters is investigated and effectiveness of ANN is scrutinized.

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27

Zhao, Xiaoxia. "Unsteady flow in the Third Navigation Channel, Gezhouba Water Control Project, China". Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80113.

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Based on the de St Venant Equations, the Preissmann's implicit finite difference scheme, and the double sweep algorithm, a mathematical model for one-dimensional subcritical unsteady flow in the Third Navigation Channel at the Gezhouba Water Control Project, China, has been developed. The model has been calibrated and verified using the prototype test data. All conceivable factors affecting wave propagation have been studied parametrically. The side discharge method is considered to be the best way to reduce the amplitudes of both water surface elevation and velocity variations caused by unsteady flow due to the emptying of the lock chamber. Using side discharges to distribute the discharge from the lock chamber along the channel, instead of concentrated discharge at the upstream boundary, improves greatly the navigation conditions.
Master of Science

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28

Stoffberg, Francis W. "Evaluation of incipient motion criteria for rock in Reno mattresses and rip rap". Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/3004.

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Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2005.
There has always been some debate in the past about the most effective and economical type of revetment to be used to combat or prevent erosion in rivers and channels. Some of the most common materials used for these mitigation measures are gabions, Reno mattresses and rip rap. A study done by the Colorado State University (CSU, 1984), comprised hydraulic tests of Reno mattresses used as a channel bed revetment. The result were compared with those of rip rap. This thesis mainly deals with the evaluation of incipient motion conditions for rock used in Reno mattresses and as rip rap. In this thesis the results of the CSU study and the design criteria of Maccaferri are evaluated and compared with the result obtained when applying the stream power theory and the Shields' theory with respect to incipient motion. This thesis includes the theory with respsect to incipient motion conditions, background to the CSU study and comparisons of the results of the CSU study and Maccaferri's design criteria with theoretical calculations. A cost comparison of Reno mattresses and rip rap as channel bed revetment measures, as well as conclusions and recommendations with regard to the design and use of these options, are also included. The frame of reference for this thesis is the set of CSU test results. The calibrations achieved, proposals made and accuracy of conclusions thus depend on those results.

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29

Villanueva, Evelyn. "Risk assessment of rock surface spillway erosion using parametric studies". Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-07022007-155027.

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30

Thompson, Seth D. "Reservoir Applications of Arced Labyrinth Weirs". DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7700.

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In recent years, magnitudes of flood estimates used in hydraulic design have increased for many reservoirs. Consequently, many existing spillways are now deficient as they do not meet current discharge capacity requirements. To rehabilitate existing, fixed-width spillways, labyrinth weirs are often viable solutions. For reservoir applications, arcing labyrinth weirs into the reservoir increases hydraulic efficiency. This results from better cycle orientation to the approaching flow field. This study supplements available arced labyrinth weir hydraulic data by observing flow characteristics of three laboratory-scale physical models and two numerical (CFD) models. Physical model results provide head (energy)-discharge data and empirical coefficients for hydraulic design. Results also show that increasing the arc angle improves efficiency at H/P<0.3, where H/P is upstream piezometric head divided by weir height; after which, efficiency improvements diminish as downstream submergence also increases. The purpose of the CFD analysis was to assess the appropriateness of CFD as a design tool for arced labyrinth weir head-discharge relationship development. The CFD model results found good agreement with the physical model data indicating CFD’s usefulness as a hydraulic design tool; however, it is recommended that CFD models be calibrated to reliable laboratory or field data. This study’s data may be used, with sound engineering judgement, to aid in hydraulic design of arced labyrinth weirs

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31

Anderson, Brett Gordon. "Quantifying the interaction between riparian vegetation and flooding : from cross-section to catchment scale /". Connect to thesis, 2006. http://repository.unimelb.edu.au/10187/2086.

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This study investigates whether the flood regime in a catchment is sensitive to the condition of riparian vegetation along the river network. The research is based on a comprehensive assessment and synthesis of field and laboratory measurements of vegetation flow resistance. A new numerical model is developed to estimate the roughness characteristics of multi-species riparian assemblages at a cross-section. Reach-scale and catchment-scale flood routing models are then applied to estimate the impact of vegetation on flood characteristics at successively larger scales. The investigation reveals that when riparian vegetation is removed at catchment-scale, peak stage declines as channel capacity increases but is also increased as the upstream catchment responds more rapidly to rain. In fact, the two competing impacts tend to cancel out leaving flood peak stage relatively insensitive to riparian condition. However, the overbank duration of a flood and flow speeds (including wave celerity) were both found to be sensitive to vegetation condition; respectively increasing and decreasing with density of vegetation. The first stage of this research examines the magnitude of the vegetation contribution to overall channel roughness, and established a means to predict it. The features of the flow resistance generated by six plant types (mature trees; grasses; aquatic plants; flexible saplings; and large woody debris) were distilled from a comprehensive review of over 160 existing publications (Chapter 2).

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32

Powell, George Erick. "Examination, application, and evaluation of geomorphic principles and resulting water quality in Midwest agricultural streams and rivers". Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1148992105.

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33

Hopton, Stephen. "Modelling open channel flow". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11594/.

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The study of open channel flow and dam breaking is not a new topic in computational fluid dynamics. However it has only recently started to gain significant attention from researchers using meshless methods, i.e. numerical modelling techniques which do not rely on the use of a mesh to discretise the domain. The research presented here is an attempt to use the meshless method known as smoothed particle hydrodynamics (SPH) to simulate the flow of water down a channel. Hydra, a pre-existing SPH code designed originally for astrophysical simulations, was converted to simulate water flow and then applied to the problem of dam bursting and flow over a weir. The conversion of the code to its new purpose was verified by simple code tests and then extensive validation was performed via the modelling of multiple dambreaks. The validation process can be split into three broad categories: 1) Comparison against the published data gained from other numerical methods both meshless and traditional. 2) Comparison against physical experiments performed by the author. 3) Comparison against independent experimental data found in the literature. Hydra in its newly converted form was satisfactorily applied to the majority of the tests presented to it and the same level of accuracy was achieved as with any of the other codes tested. A limit to the SPH method for performing this type of simulation was proposed based on particle number, smoothing length and initial conditions. A formula for the calculation of the number of ghost particles required to prevent spurious boundary pressures was also proposed. An analysis of various kernels used by different SPH researchers was presented and it was discovered that a relatively simple cubic spline kernel proved sufficient and that increasing complexity did not provide an increase in solution accuracy. The flow of water over a weir was presented next and results compared to published data which utilised a leading mesh based fluid simulation package. Results gained from Hydra simulations showed good downstream water level prediction but overestimation of upstream levels. A steady state solution was achieved within a similar timeframe compared to the grid based method. It was concluded that use of the SPH method and the Hydra code in particular can provide solutions to problems involving water flow down a channel and accuracy on the dambreak tests was equal to any rival codes/methods tested. However when the complexity of the boundaries involved in the model increased there was some evidence that the CFX simulation package could be used to achieve a more accurate solution than Hydra. Suggestions for continuation of research into Hydra as a water flow modelling code are presented in addition to recommendations for improving the experimental methods used.

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34

Anh, Tran Ngoc. "Hydraulic modeling of open channel flows over an arbitrary 3-D surface and its applications in amenity hydraulic engineering". 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/136144.

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Capello, Stephanie V. Allen Peter M. "Modeling channel erosion in cohesive streams of the Blackland Prairie, Texas at the watershed scale". Waco, Tex. : Baylor University, 2008. http://hdl.handle.net/2104/5220.

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Beaman, Faye. "Large eddy simulation of open channel flows for conveyance estimation". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11130/.

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Prediction of conveyance capacity in open channel flows is complex and requires adequate modelling of flow features such as secondary circulation cells and, specifically for over-bank channels, the momentum exchange that occurs at the main channel/floodplain interface. A variety of conveyance estimation methods have been developed with the objective of accurately capturing these flow characteristics through a simplified user-friendly approach. However, these methods usually require calibration of one or more empirical constants. Within this thesis in-bank and over-bank channels have been numerically simulated using Large Eddy Simulation (LES) in order to predict accurate open channel flow behaviour. The LES results are validated against experimental data and then utilised to advise on values of calibration constants f, λ and Γ within a conveyance estimation method, the Shiono and Knight Method (SKM), which has recently been adopted by the Environment Agency (EA) for England and Wales as part of its new Conveyance Estimation System (CES). The LES results are shown to accurately predict the flow features, specifically the distribution of secondary circulations in in-bank channels of aspect ratio as large as 40 and for over-bank channels at varying depth and width ratios. The LES derived f, λ and Γ values are then utilized in the analytical solution of the SKM in order to compute depth averaged velocity profiles for comparison to LES results, producing very good agreement with simulated and experimental profiles. As well as the derivation the calibration constants, the apparent shear stress at the main channel/floodplain interface is investigated and the contributions from both Reynolds stress and secondary circulation terms compared. Also, instantaneous velocity data available from monitor points at the main channel/floodplain interface within over-bank channel simulations is utilized to investigate wave periods of interfacial vortices through spectral analysis. Comparable result to available experimental and stability analysis data are obtained.

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37

Keogh, Darren Paul. "An experimental investigation on the flow characteristics of open-channel slot flow". Thesis, Edinburgh Napier University, 2000. http://researchrepository.napier.ac.uk/Output/4273.

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Blunden, L. S. "New approach to tidal stream energy analysis at sites in the English Channel". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/73610/.

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Tidal stream power generation offers the prospect of predictable, low-CO2 power at a number of locations around the UK and the world. Previous assessments of tidal energy resources have taken the form of desk studies based on simplified navigational data. Where numerical model data has been used it has been at too low a resolution to capture high velocity tidal flows constrained by coastal topography. Analytical solutions for maximum energy extraction in simple tidal channels have been produced, but they have not been extended to more complex open-boundary cases such as flow around headlands and islands. There is therefore a role for site-specific numerical modelling, which when validated, offers the twin advantages of a high-resolution picture of the resource and allowing simulation of momentum extraction within the model to take place. In order to parameterize the sub-grid-scale momentum extraction in such models, a new analytical model of the velocity reduction in a large array of tidal turbines has been derived. The model extends previous models of large wind turbine arrays and uses analogies with flow through submerged vegetation. It provides an equivalent added drag coefficient suitable for use in a 2-D coastal numerical model. A numerical model of the flows in the region of the Portland Bill headland has been produced, forced by tidal elevations at the free boundary. A site selection exercise was carried out for the Portland Bill location and an area of around 12 km2 was identified as having a high potential for development using mean cubed speed found through tidal analysis of model results without energy extraction. A large tidal stream generator array has also been simulated within the Portland Bill model—linked to the new model for momentum extraction—and was found to have a significant effect on the tidal parameters in the locality. This was the first time that a large tidal array has been simulated in a realistic coastal domain of large extent, with a parameterization that takes into account the interaction of the turbines with the rough-wall flow in the natural state. Results predict that there is a region downstream of the array extending approximately 5–10 km around the simulated tidal stream turbine array in which the tidal stream ellipse major axis is reduced by at least 5%. In the area of momentum extraction the principal semi-diurnal tidal stream ellipse major axis length was reduced by 10–15%.

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Sharifi, Soroosh. "Application of evolutionary computation to open channel flow modelling". Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/478/.

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This thesis examines the application of two evolutionary computation techniques to two different aspects of open channel flow. The first part of the work is concerned with evaluating the ability of an evolutionary algorithm to provide insight and guidance into the correct magnitude and trend of the three parameters required in order to successfully apply a quasi 2D depth averaged Reynolds Averaged Navier Stokes (RANS) model to the flow in prismatic open channels. The RANS modeled adopted is the Shiono Knight Method (SKM) which requires three input parameters in order to provide closure, i.e. the friction factor (\(f\)), dimensionless eddy viscosity (λ) and a sink term representing the effects of secondary flow (Γ). A non-dominated sorting genetic algorithm II (NSGA-II) is used to construct a multiobjective evolutionary based calibration framework for the SKM from which conclusions relating to the appropriate values of \(f\), λ and Γ are made. The framework is applied to flows in homogenous and heterogeneous trapezoidal channels, homogenous rectangular channels and a number of natural rivers. The variation of \(f\), λ and Γ with the wetted parameter ratio (\(P_b\)/\(P_w\)) and panel structure for a variety of situations is investigated in detail. The situation is complex: \(f\) is relatively independent of the panel structure but is shown to vary with P\(_b\)/P\(_w\), the values of λ and Γ are highly affected by the panel structure but λ is shown to be relatively insensitive to changes in \(P_b\)/\(P_w\). Appropriate guidance in the form of empirical equations are provided. Comparing the results to previous calibration attempts highlights the effectiveness of the proposed semi-automated framework developed in this thesis. The latter part of the thesis examines the possibility of using genetic programming as an effective data mining tool in order to build a model induction methodology. To this end the flow over a free overfall is exampled for a variety of cross section shapes. In total, 18 datasets representing 1373 experiments were interrogated. It was found that an expression of form \(h_c\)=A\(h_e\)\(^{B\sqrt S_o}\), where \(h_c\) is the critical depth, \(h_e\) is the depth at the brink, \(S_o\) is the bed slope and A and B are two cross section dependant constants, was valid regardless of cross sectional shape and Froude number. In all of the cases examined this expression fitted the data to within a coefficient of determination (CoD) larger than 0.975. The discovery of this single expression for all datasets represents a significant step forward and highlights the power and potential of genetic programming.

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Yorke, Christopher Philip. "Direct numerical simulation of a strained and recovered channel flow with Reynolds-averaged Navier-Stokes model comparisons". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/47118/.

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Biglari, Bahram. "Turbulence modeling of clear-water scour around bridge abutment in compound open channel". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/21780.

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Fricano, Joseph William. "Integrated fuel performance and thermal-hydraulic sub-channel models for analysis of sodium fast reactors". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76919.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 191-197).
Sodium Fast Reactors (SFR) show promise as an effective way to produce clean safe nuclear power while properly managing the fuel cycle. Accurate computer modeling is an important step in the design and eventual licensing of SFRs. The objective of this work was to couple a model for metal fuel performance to a sub-channel analysis code to more precisely predict critical phenomena that could lead to pin failure for steady-state and transient scenarios. The fuel code that was used is the recently developed and benchmarked FEAST-METAL code. The sub-channel analysis code that was selected is COBRA-IV-I. This code was updated with current correlations for sodium for pressure drop, mixing, and heat transfer. The new code, COBRA-IV-I-MIT was then validated with experimental data from the Oak Ridge National Laboratory (ORNL) 19-Pin Bundle, the Toshiba 37-Pin Bundle, and the Westinghouse Advanced Reactors Division (WARD) 61-Pin Bundle. Important topics that were addressed for coupling the codes include the following. The importance of azimuthal effects in the fuel pin: FEAST only evaluates the fuel in two-dimensions, assuming azimuthal symmetry; however, coupling to COBRA produces an azimuthal temperature distribution. The acceptability of assuming a two-dimensional fuel rod with an average temperature was examined. Furthermore, how the fuel pin evolves over time affects the assembly geometry. How well a two-dimensional fuel rod allows for an accurate description of the changing assembly geometry was also considered. Related to this was how the evolution of the assembly geometry affects its thermal hydraulic behavior, which determined the exact form of coupling between the codes. Ultimately one-way coupling was selected with azimuthal temperature averaging around the fuel pin. The codes were coupled using a wrapper, the COBRA And FEAST Executer (CAFE), written in the Python programming language. Data from EBR-II was used to confirm and verify CAFE. It was found that the number of axial nodes used in FEAST can have a large effect on the result. Finally FEAST was used to parametrically study three different pin designs: driver fuel, radial blanket, and tight pitch breed and bum fuel. This study provides data for pin expected life in assembly design.
by Joseph William Fricano.
Ph.D.

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Stewart, Robert L. III. "DECELERATING OPEN CHANNEL FLOW OVER GRAVEL: TURBULENCE STRUCTURE & SENSOR DEVELOPMENT". UKnowledge, 2014. http://uknowledge.uky.edu/ce_etds/25.

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This dissertation describes investigations of fully turbulent decelerating hydraulically roughbed flow over gravel and the development of technology to measure turbulence and associated sediment transport in streams. Theory is developed for predicting velocity distributions in simple uniform flow using the asymptotic invariance principle and tested using laboratory and field collected data. A mixed scale is developed that accounts for bed derived turbulent structures throughout the flows depth and is used to parameterize the external boundary’s effect on the flow for the logarithmic and outer layers. The asymptotic invariance principle and similarity analysis is conducted for the equations of motion in the outer region of decelerating flow over gravel to define equilibrium conditions for this class of flows with the velocity scale is the freestream velocity. The combination of time series and time averaged statistical analysis of turbulent flow is used to elucidate the structure of flow under decelerating conditions. Time averaged statistical measures of turbulence confirm results of others for higher Froude number approaching transcritical and time series analysis shows the effects of decelerating flow on turbulence to be frequency dependent. Wireless velocity sensors were developed and found capable of measuring time averaged velocity and able to resolve macroturbulence from time series data. A semi-theoretical model of elastic deformation of cantilever beams under hydraulic forcing was coupled with circuit theory to develop a calibration procedure for the VBS that requires only three measurement points, one of which is at zero velocity. Light based sensors are developed to estimate light attenuation in water for ecological research or estimating sediment concentration in water. A semi-theoretical scaling of light attenuation and sediment properties was developed which predicts light attenuation from sediment properties. The combination of new theory on open channel velocity, turbulent structure and field sensors for measuring turbulence and sediment offers the possibility to extend our laboratory knowledge to realistic flow situations.

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Chipongo, Kudzai. "Effects of lateral inflow on oxygen transfer and hydraulics in open channel flows". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2053.

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The design of channels or hydraulic structures requires the correct prediction of flow properties such as depth of flow. In uniform open channel flows, a one dimensional (1-D) approach which assumes hydrostatic pressure distribution, negligible air entrainment and uniform velocity in the direction of flow is often used. Spatially varied flow (SVF) is a special type of open channel flow in which the discharge increases or decreases along the channel due to lateral inflow or outflow, respectively. As a result, this intricate flow is associated with momentous turbulence and velocity fluctuations in all three directions of flow. Researchers have proven that using the 1-D approach for predicting SVF properties yields erroneous results. This thesis details research conducted (i) to improve the accuracy of the current one-dimensional equation, (ii) to quantify the amount of oxygen transferred by lateral inflow and (iii) to predict turbulence characteristics using three-dimensional turbulence model. First, it is proposed that SVF due to lateral inflow, which is the focus of this study, can be likened to multiple jets in crossflow and open channels with emergent vegetation. In these two cases, the multiple jet and the vegetation stems resemble a solid cylindrical object blocking the crossflow thus effects of the drag force are vital. Similar to open channel with emergent vegetation studies, a new equation accounting for the drag force was developed and tested for different arrangements of SVF. Results indicated significant improvements in predicting water surface profiles. Second, similar to weir flow the amount of oxygen transferred by lateral inflow was measured under different flow conditions and various modes of lateral inflow entry to the channel. The amount of dissolved oxygen (DO) in a body is vital for improving water quality. Results indicated that increasing jet velocity, discharge height and number of jets at optimum water depth in the receiving channel enhances oxygen transfer. Finally, three-dimensional computational fluid dynamics (CFD) analysis of an open channel receiving inflow from multiple jets in tandem issuing from a circular nozzle was conducted using the relatively low cost Reynolds-averaged Navier-Stokes (RANS) models namely the realizable k-ε, shear stress transport (SST) k-ω and the Reynolds stress model (RSM) based on their prominence in jet in crossflow studies. RANS models failed to predict turbulence characteristics within the lateral inflow region although average velocities in the longitudinal direction were acceptable. On the leeward side of the jet, RANS models failed to capture the downward velocity vectors resulting in major deviations in vertical velocity. It can be concluded that standard turbulence models are incapable of predicting the complex characteristics of SVF. However, turbulence models remain superior to the 1-D approach.

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Diaz-Ramirez, Jairo Nelvedir. "ASSESSMENT OF UNCERTAINTY IN FLOW MODEL PARAMETERS, CHANNEL HYDRAULIC PROPERTIES, AND RAINFALL DATA OF A LUMPED WATERSHED MODEL". MSSTATE, 2007. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07032007-140341/.

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Among other sources of uncertainties in hydrologic modeling, spatial rainfall variability, channel hydraulic variability, and model parameter uncertainty were evaluated. The Monte Carlo and Harr methods were used to assess 90% certainty bounds on simulated flows. The lumped watershed model, Hydrologic Simulation Program FORTRAN ? HSPF, was used to simulate streamflow at the outlet of the Luxapallila Creek watershed in Mississippi and Alabama. Analysis of parameter uncertainty propagation on streamflow simulations from 12 HSPF parameters was accomplished using 5,000 Monte Carlo random samples and 24 Harr selected points for each selected parameter. Spatial rainfall variability propagation on simulated flows was studied using six random grid point sets of Next Generation Weather Radar (NEXRAD) rainfall data (i.e., 109, 86, 58, 29, 6, and 2 grid points) from the baseline scenario (115 NEXRAD grid points). Uncertainty in channel hydraulic properties was assessed comparing the baseline scenario (USGS FTABLE) versus the EPA RF1 FTABLE scenario. The difference between the baseline scenario and the remaining scenarios in this study was evaluated using two criteria: the percentage of observed flows within the HSPF 90% certainty bounds (Reliability) and the width of the HSPF 90% certainty bounds (Sharpness). Daily observed streamflow data were clustered into three groups to assess the model performance by each class: below normal, normal, and above normal flows. The parameter uncertainty propagation results revealed that the higher the model Sharpness the lower the model Reliability. The model Sharpness and Reliability results using 2 NEXRAD grid points were markedly different from those results using the remaining NEXRAD data sets. The hydraulic property variability of the main channel affected storm event paths at the watershed outlet, especially the time to peak flow and recessing limbs of storm events. The comparison showed that Harr?s method could be an appropriate initial indicator of parameter uncertainty propagation on streamflow simulations, in particular for hydrology models with several parameters. Parameter uncertainty was still more important than those sources of uncertainty accomplished in this study because all of the median relative errors of model Reliability and Sharpness were lower than +/- 100%.

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Thorburn, John M. "HYDRAULIC EFFECTS OF PERPENDICULAR WATER APPROACH VELOCITY ON METER GATE FLOW MEASUREMENT". DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2190.

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Accurate flow measurement is required to effectively manage water resources. California Senate Bill X7-7 (SB X7-7), legislates this need by requiring agricultural water providers serving areas greater than 25,000 acres to develop an Agricultural Water Management Plan (AWMP) and adopt pricing based at least partly on volumetric water deliveries (DWR, 2009). This study focused on two of the most common flow measurement/flow control devices used in California open channel water conveyance systems: the circular meter gate and the rectangular meter gate. Testing was conducted on three Armco-type (round gates over round discharge pipe) gates measuring 12”, 18”, and 24” and two rectangular gates (rectangular gates over round discharge pipe) measuring 18” and 24”. The three round gates used in the study were the Model 101C produced and provided by Fresno Valve and Castings Incorporated. The two rectangular meter gates were manufactured by Mechanical Associates located in Visalia, California and provided by the San Luis Canal Company located in Dos Palos, California. Testing was conducted in an outdoor laboratory setting at the Irrigation Training and Research Center’s (ITRC) Water Resources Facility at the California Polytechnic State University in San Luis Obispo, California under a variety of flow conditions as experienced in the field in order to: 1) evaluate the effectiveness of these gates as flow measurement devices and determine whether they meet the volumetric accuracy requirements outlined in SB X7-7, 2) develop standards for installation and use that improve flow measurement accuracy, 3) configure more accurate gate rating tables based on updated coefficient of discharge values, and 4) determine if additional gate rating tables are needed for “high” supply channel velocities. The meter gate was set perpendicular to the supply channel. Baseline data was first collected through testing with low supply channel water velocities. Additional testing was then conducted with high supply channel water velocities to analyze the effect on the coefficient of discharge. Based on previous studies it was hypothesized that as the Froude number (FR#) in the supply channel increased (water approach velocity increased), the coefficient of discharge would decrease as a result of an increase in energy needed for the perpendicular velocity transition. Data evaluation, however, indicated no statistically significant effect of water approach velocity on the coefficient of discharge for the 12”, 18” and 24” circular gates or the 18” and 24” rectangular gates at an α-level = 0.01. When operating the gates under recommended conditions relative flow uncertainty was within +/- 5%. This meets the accuracy requirements set by SB X7-7 for turnout flow measurement devices. Based on the results of this study, Cd values do not need to be adjusted for Froude numbers up to 0.35 for any of the studied gates. It should be noted, however, that while most meter gates used will be in conditions where supply channel Froude numbers do not exceed 0.35, further research is needed to study potential effects from Froude numbers exceeding the range found in this study.

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Midboe, Finn, i Håkan Persson. "Simulering av översvämningar i Byälven". Thesis, Uppsala University, Department of Earth Sciences, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88868.

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Severe floods caused by heavy autumn rains in year 2000 raised the question whether measures to reduce the damage from high water levels, in the area surrounding lake Glafsfjorden and along the river Byälven down to lake Vänern, are possible. One option is to reduce flow resistance along the river and thereby lower the maximum water level a given inflow would cause. Good knowledge of hydraulic and hydrological conditions is necessary in order to estimate the effect of such flow-reducing measures. In order to quantify such effect a 1-dimensional hydraulic flow model has been set up for the river Byälven using the software package MIKE 11. The model is more detailed, especially concerning topography and bathymetry, than earlier models used for studies of the river. Boundary conditions consist of measured inflows, the level of the lake Vänern and runoff calculated using the HBV-model. The model was calibrated for two different floods and a good fit to measured water levels was obtained for both these periods. Using the calibrated model critical sections, causing much flow resistance during high floods, were identified. With that knowledge different measures to reduce high water levels was adopted to the model both individually and combined with each other and the model was run with boundary conditions mainly from the flood in year 2000. The most radical measures simulated resulted in a lowering of the maximum water in the two largest reservoirs Glafsfjorden and Harefjorden with 78 and 97 cm respectively. A more modest combination of measures gave water levels 48 and 84 cm lower than a model run without changes. Some combinations of relatively small measures lowered the maximum water level by a few decimeters. The simulation results give good guidance to further investigations and decisions of actual changes. The model constitutes a useful tool when making flood maps of the area and if water level forecasts would be needed during future floods.

Allvarliga översvämningar i samband med höstregn år 2000 väckte frågan om det går att vidta åtgärder för att minska skadorna vid höga flöden i området runt Glafsfjorden och längs Byälvens sträckning ner till Vänern. Ett alternativ är att med åtgärder längs älven underlätta vattnets utflöde och på så sätt minska den högsta vattennivå ett givet flöde orsakar. God kunskap om hydrauliska och hydrologiska förhållanden behövs för att bedöma nyttan av olika åtgärdsalternativ. För att kunna avgöra effekterna av olika åtgärdsalternativ har en 1-dimensionell strömningsmodell satts upp för Byälven i programverktyget MIKE 11. Modellen är mer detaljerad, framförallt beträffande höjdinformationen, än tidigare modeller som använts för studier av Byälven varit. Randvillkor till modellen utgörs av registrerade inflöden, Vänerns vattenstånd och avrinning modellerad med HBV-modellen. Modellen har kalibrerats för två översvämningsperioder och god anpassning uppnåddes för de vattenstånd som dessa situationer representerar och med dess hjälp har sedan älven studerats och områden som bromsar flödet har kunnat identifieras. Med kunskap om vilka områden som begränsar flödet mest har ett antal olika åtgärder simulerats i modellen, både var för sig och kombinerade med varandra. Randvillkoren för översvämningen år 2000 behölls och förändringarna lades in i modellen. De extremaste åtgärderna som simulerats resulterade i minskningar av de högsta vattennivåerna i de två största vattenmagasinen Glafsfjorden och Harefjorden med 78 respektive 97 cm. Mer realistiska åtgärdspaket gav minskningar med i storleksordningen 48 respektive 84 cm och även relativt små ingrepp gav minskningar på några decimeter. Simuleringsresultaten ger god vägledning för vidare undersökningar av och beslut om konkreta åtgärder i Byälven. Dessutom utgör modellen ett bra verktyg för att ta fram översvämningskartor och för att prognostisera vattennivåer vid nya översvämningssituationer.

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Sahiner, Halit. "Hydraulic Characteristics Of Tyrolean Weirs Having Steel Racks And Circular-perforated Entry". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614247/index.pdf.

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Tyrolean type water-intake structures are commonly used on mountain rivers to supply water to hydropower stations. The amount of water to be diverted from the main channel is the major concern in these kind of structures and should not be less than the design discharge. In this study a physical model of a Tyrolean type water-intake structure was built at the laboratory and the diverted flow from the main channel through the intake structure having steel racks and perforated plates of different types were measured. The experiments were conducted in two stages. In the first stage the tests were carried out with only steel racks having three different bar openings and slopes, and in the second stage, perforated screens of three different circular openings and screen slopes were used. Applying dimensional analysis to the related parameters of the system the dimensionless terms were defined for the water capture efficiency and discharge coefficient of the system, and their variations with the relevant parameters were plotted. Using these diagrams one can determine the amount of water to be diverted by a Tyrolean weir of known geometry and main channel discharge.

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Kucuktepe, Omer Ilker. "Initiation Of Motion Of Coarse Solitary Particles On Rough Channel Beds". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611324/index.pdf.

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In this study the incipient motion of coarse solitary particles on channel beds having different roughness heights was experimentally investigated. The experiments were conducted in a tilting flume of a rectangular cross-section having a working length of 12 m and a rough bed composed of at least 2 layers of coarse gravel of almost constant size. The roughness material of the channel bed was changed three times. The slope of the channel bed and the discharge are two main parameters that determine the initiation of motion of a given particle. The artificial particles tested in the experiments were obtained by mixing cement and iron dust at certain ratios. Dimensionless hydraulic parameters determined from theoretical analysis were related to each other. Flow depths, velocity profiles were measured and flow conditions that represent the critical conditions of initiation of motion were expressed in terms of critical velocities and shear velocities. The results were compared with the previous studies&rsquo
results.

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50

Brockman, Ruth Roseann. "HYDRAULIC GEOMETRY RELATIONSHIPS AND REGIONAL CURVES FOR THE INNER AND OUTER BLUEGRASS REGIONS OF KENTUCKY". UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/56.

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Hydraulic geometry relationships and regional curves are used in natural channel design to assist engineers, biologists, and fluvial geomorphologists in the efforts undertaken to ameliorate previous activities that have diminished, impaired or destroyed the structure and function of stream systems. Bankfull channel characteristics were assessed for 14 United States Geological Survey (USGS) gaged sites in the Inner Bluegrass and 15 USGS gaged sites in the Outer Bluegrass Regions of Kentucky. Hydraulic geometry relationships and regional curves were developed for the aforementioned regions. Analysis of the regression relationships showed that bankfull discharge is a good explanatory variable for bankfull parameters such as area, width and depth. The hydraulic geometry relationships developed produced high R2 values up to 0.95. The relationships were also compared to other studies and show strong relationships to both theoretical and empirical data. Regional curves, relating drainage area to bankfull parameters, were developed and show that drainage area is a good explanatory variable for bankfull parameters. R2 values for the regional curves were as high as 0.98.

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