Operational Safety in Shutdown of In-Pipe Drag-Based Turbines: Pressure Surge and Blade Torque Considerations

Operational Safety in Shutdown of In-Pipe Drag-Based Turbines: Pressure Surge and Blade Torque Considerations | 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 Article Operational Safety in Shutdown of In-Pipe Drag-Based Turbines: Pressure Surge and Blade Torque Considerations Mohammad Karimipour Parashkooh, Nima Hasanzadeh, Peyman Sobhani, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8928995/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Hydraulic transients in drag-based in-pipe turbines during sudden operational changes can induce pressure pulsations, water hammer, cavitation, and column separation in pipeline components located both upstream and downstream of the turbine. Additionally, the torque imposed on turbine blades is a critical concern, as frequent operational changes can accelerate blade fatigue and potentially lead to structural failure. This study integrates the Method of Characteristics (MOC) and Computational Fluid Dynamics (CFD) to model transient phenomena resulting from the abrupt stoppage of a hydrodynamic in-pipe turbine. The analysis evaluates how varying deceleration rates influence pressure surges, pressure pulsations, and torque amplification on blades across different blade counts and turbine geometries. The results demonstrate that stoppage time significantly affects torque escalation and confirm that turbine geometry and blade configuration strongly influence the magnitude of pressure surges during transient events. Detailed scenario analyses further reveal that specific configurations exhibit greater susceptibility to extreme pressure fluctuations, thereby creating substantial operational and reliability challenges. Physical sciences/Energy science and technology Physical sciences/Engineering Hydraulic transients In-pipe drag-based turbine Method of Characteristics (MOC) Pressure surge Blade torque Water hammer Full Text Additional Declarations No competing interests reported. Supplementary Files Highlight.docx GraphicalAbstract.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 15 Apr, 2026 Reviews received at journal 10 Apr, 2026 Reviewers agreed at journal 08 Apr, 2026 Reviewers agreed at journal 02 Apr, 2026 Reviews received at journal 18 Mar, 2026 Reviewers agreed at journal 08 Mar, 2026 Reviewers invited by journal 03 Mar, 2026 Editor invited by journal 26 Feb, 2026 Editor assigned by journal 24 Feb, 2026 Submission checks completed at journal 24 Feb, 2026 First submitted to journal 20 Feb, 2026 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. 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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-8928995","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":600096348,"identity":"fe0a2ad3-0f6a-47fa-aeee-60aa2ef0ecad","order_by":0,"name":"Mohammad Karimipour Parashkooh","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"Karimipour","lastName":"Parashkooh","suffix":""},{"id":600096349,"identity":"2a9fba4b-0548-4bb9-955f-0f9fe9976343","order_by":1,"name":"Nima Hasanzadeh","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Nima","middleName":"","lastName":"Hasanzadeh","suffix":""},{"id":600096350,"identity":"d1ea8b9d-de14-4ad3-9c4a-3a4fc3b4b2f4","order_by":2,"name":"Peyman Sobhani","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Peyman","middleName":"","lastName":"Sobhani","suffix":""},{"id":600096351,"identity":"dcd2e4d8-5b4f-437d-8353-d5a30739cd76","order_by":3,"name":"Amir Farhad Najafi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIie3RsQrCMBCA4SuBTle7XqHoK5wEagehr6L0AXyBDp3qIs4+TkTI5AMUHKS4OnQSBxVb0TlxE8y3Be7nDgLgOL9IKACCIYbvN5oTf9YnEqNSfJMASGAlLO8Kq2DbpgXHsl4ouBYQT0pDQnqQE2nGpM7BW2nAWJnWHFdM5N9eCQQlIJmKkUZ5pQej3HRb7jYJa0woqhiZchBWW8ZdkkZrRtqfeBdrMifD7rADXTgLl/OmORfTzJj0xGdK9b9qxWvt5hzHcf7VE4nnMRVDw6fKAAAAAElFTkSuQmCC","orcid":"","institution":"University of Tehran","correspondingAuthor":true,"prefix":"","firstName":"Amir","middleName":"Farhad","lastName":"Najafi","suffix":""}],"badges":[],"createdAt":"2026-02-20 20:53:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8928995/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8928995/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104404055,"identity":"8d026782-60cd-433f-a188-6a332119cbb2","added_by":"auto","created_at":"2026-03-11 12:19:39","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":17198,"visible":true,"origin":"","legend":"","description":"","filename":"Highlight.docx","url":"https://assets-eu.researchsquare.com/files/rs-8928995/v1/71ed7b66f82f7327350ea053.docx"},{"id":104098541,"identity":"a1d8f4bf-5290-40a7-9f91-37b967def06b","added_by":"auto","created_at":"2026-03-06 18:35:17","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1030346,"visible":true,"origin":"","legend":"","description":"","filename":"GraphicalAbstract.docx","url":"https://assets-eu.researchsquare.com/files/rs-8928995/v1/dab2c19b3d7a09ecfb001769.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Operational Safety in Shutdown of In-Pipe Drag-Based Turbines: Pressure Surge and Blade Torque Considerations","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Hydraulic transients, In-pipe drag-based turbine, Method of Characteristics (MOC), Pressure surge, Blade torque, Water hammer","lastPublishedDoi":"10.21203/rs.3.rs-8928995/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8928995/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eHydraulic transients in drag-based in-pipe turbines during sudden operational changes can induce pressure pulsations, water hammer, cavitation, and column separation in pipeline components located both upstream and downstream of the turbine. 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