14576

13146

كارشناسي ارشد

مهندسي آب (سازه هاي آبي)

اصفهان : دانشگاه صنعتي اصفهان

1397

پانزده، 124ص. : مصور، جدول، نمودار

منوچهر حيدرپور

جهانشير محمدزاده هابيلي

جهانگير عابدي كوپايي، سعيد سلطاني كوپائي

1398/02/08

كتابنامه

مهندسي كشاورزي

مهندسي كشاورزي

1398/02/10

2529795

Impact of upstream and downstream face slope of trapezoidal broad crested weir on pressure distribution Shima Rezaie s rezaie@ag iut ac ir March 4 2019 Department of Water Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Manouchehr heidarpour heidar@cc iut ac irAbstractThe weirs are the simplest least expensive and most accurate hydraulic structures for controlling and measuringwater flow in open channels and differet shapes The most common types of weirs are trapezoidal broad crestedweirs because of the high precision in determining amount of discharge When designing weirs hydraulic designparameters are very important and the most important parameters are velocity and pressure In this study thehydraulic characteristics on two broad crested weirs were considered at the Hydraulic Laboratory of IsfahanUniversity of Technology Flow profiles velocity profiles over the upstream and crest and pressure along the weirwere investigated Two models were up30 down45 and up45 down30 Three expriments were conducted on eachweirs and mentioned parameters were taken for three discharges of each models Laboratory results of watersurface profiles showed with increasing discharge the critical depth is transmitted to the upstream of crest anddecreasing the upstream face slope transmitted the critical depth to the downstream of crest Laboratory resultsof velocity showed with increasing discharge velocity distribution on the crest become more uniform and velocitynear the floor is maximum and near the water surface is minimum Decreasing the upstream face slope increasedvelocity in the heel of weir and velocity over the crest become uniform Laboratory results of pressure distributionshowed that in the upstream of the crest decreasing discharge decreased pressure and in the downstream of thecrest decreasing discharge increased pressure Then using the FLOW 3D software and utilizing the RNG K eturbulence model the flow over broad crested weir was simulated for six existing experiments and numericalresults and experimental results were compared The results showed a high agreement between numerical andexperimental results By simulating different models flow hydraulic parameters such as boundry layer flowseparation discharge coefficient and pressure were considered Increasing the upstream face slope increasedboundry layer thickness and maximum of boundry layer thickness transmitted to downstream of the crest Changein downstream face slope doesn t have much effect on boundry layer thickness Increasing discharge decreasedboundry layer thickness Decreasing upstream face slope decreased separation zone discharge coefficientincreased Change in downstream face slope doesn t have much effect on separation zone and dischargecoefficient Analyzing the pressure on the crest showed that increasing the downstream face slope decreasedpressure on the crest and the probility of occurrence of cavitation increased but it doesn t have much effect onpressure in the upstream face slope Results showed that with decreasing upstream face slope the slope of thedrop in pressure is reduced Increasing upstream face slope reduced pressure in the upstream of crest andincreased pressure in the middle of crest Key words Broad crested weir Flow profiles Velocity profiles Pressure distribution FLOW 3D RNG K turbulence model 011

منوچهر حيدرپور

جهانشير محمدزاده هابيلي

جهانگير عابدي كوپايي، سعيد سلطاني كوپائي