Effect of deflector and crest geometry on submerged flow in a shaft spillway

Effect of deflector and crest geometry on submerged flow in a shaft spillway | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of deflector and crest geometry on submerged flow in a shaft spillway Soroush Esmaeili, Babak Lashkar-Ara This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4335453/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In this study, the impacts of a deflector located in the throat and inlet geometry of the crest on improving the hydraulic performance of a shaft spillway were investigated, and the hazards induced by the lack of timely drainage of floods in dam reservoirs were decreased to some extent. To investigate the deflection effect, three constriction specimens in the shaft throat with constriction area-to-shaft area ratios ( A d /A i ) of 0.75, 0.5 and 0.25 were considered as scenarios. In each scenario, the flow conditions through 12 different spillway specimens with crown wheel inlets were tested, and the results were compared with the flow conditions in crown wheel spillways without a deflector (reference model). The results showed that the use of a deflector has an important role in reducing vortex flows, stabilizing changes in the water level of the reservoir and increasing the discharge coefficient of the flow. Studies on reference models have also shown that crown wheel inlets (C.W.) improve shaft spillway performance, with C.W. spillways having an average discharge coefficient 32% greater than that of shaft spillways. Finally, considering the optimal deflector factors and C.W. geometry, an optimal model was proposed for flood reservoir conditions. Dams Barrages and reservoirs Dewatering Flow characteristics Models (physical) Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4335453","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":299422493,"identity":"4d27b38e-718d-4817-830d-f0f5d743e714","order_by":0,"name":"Soroush Esmaeili","email":"","orcid":"","institution":"Jundi-Shapur University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Soroush","middleName":"","lastName":"Esmaeili","suffix":""},{"id":299422495,"identity":"3ffdcf51-0eab-470e-880a-feb643b77ba4","order_by":1,"name":"Babak Lashkar-Ara","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFElEQVRIiWNgGAWjYBACAwYeBsYGhgMMDBJsEBF+BgY2ErVINpCsxeAAAS3m7GcPfpzBcEBefnZb4ueKmnvyxjeSnz34UMEgzy92AKsWy568ZMkNDAcMN9w5dljyzLFiw2030swNZ5xhMJw5OwG7ww7kGEg+YDjAuEEivUGygS2BcduNBDNp3jaGBIPbOLScf2P8E6jFfv6M9OafDf8S7DfPSP+GX8uNHDOQwxIbbqQdk2xsS0jcIJGD3xbLGe/SLIHeT95wIy3NsrEvIXnGmTdlkjPOSOD0izl/7uGbPQz/bOfPSDO+2fAtwba/PX2bxIcKG3l+aexawIDxHzJPAKxSArdyTMB/gBTVo2AUjIJRMAIAAC3JZyIBtG7ZAAAAAElFTkSuQmCC","orcid":"","institution":"Jundi-Shapur University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Babak","middleName":"","lastName":"Lashkar-Ara","suffix":""}],"badges":[],"createdAt":"2024-04-27 21:08:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4335453/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4335453/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":69710437,"identity":"39222911-89c0-4d0b-b100-6722ffbcef5b","added_by":"auto","created_at":"2024-11-23 19:31:25","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":926697,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4335453/v1_covered_7ded7670-bf70-4f78-9fbb-2c1c16dc5cbb.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of deflector and crest geometry on submerged flow in a shaft spillway","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Dams, Barrages and reservoirs, Dewatering, Flow characteristics, Models (physical)","lastPublishedDoi":"10.21203/rs.3.rs-4335453/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4335453/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, the impacts of a deflector located in the throat and inlet geometry of the crest on improving the hydraulic performance of a shaft spillway were investigated, and the hazards induced by the lack of timely drainage of floods in dam reservoirs were decreased to some extent. To investigate the deflection effect, three constriction specimens in the shaft throat with constriction area-to-shaft area ratios (\u003cem\u003eA\u003c/em\u003e\u003csub\u003e\u003cem\u003ed\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e/A\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e) of 0.75, 0.5 and 0.25 were considered as scenarios. In each scenario, the flow conditions through 12 different spillway specimens with crown wheel inlets were tested, and the results were compared with the flow conditions in crown wheel spillways without a deflector (reference model). The results showed that the use of a deflector has an important role in reducing vortex flows, stabilizing changes in the water level of the reservoir and increasing the discharge coefficient of the flow. Studies on reference models have also shown that crown wheel inlets (C.W.) improve shaft spillway performance, with C.W. spillways having an average discharge coefficient 32% greater than that of shaft spillways. 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