Simulation of a rotor in forward flight to characterize helicopter wake signature and encounter severity

Simulation of a rotor in forward flight to characterize helicopter wake signature and encounter severity | 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 Simulation of a rotor in forward flight to characterize helicopter wake signature and encounter severity Guillaume Querinjean, Victor Colognesi, Matthieu Duponcheel, Gilles Poncelet, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6769712/v2 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Feb, 2026 Read the published version in CEAS Aeronautical Journal → Version 2 posted You are reading this latest preprint version Show more versions Abstract The development of safe and efficient air traffic separation policies relies on the accurate quantification of the wake turbulence generated by aircraft and rotorcraft, and on the accurate understanding of the upset experienced by a follower aircraft or rotorcraft if encountering such wakes. To address the existing gap in rotorcraft-specific studies, this paper first presents numerical simulations of the wake produced by a helicopter rotor in forward flight. The effect of the airspeed is investigated, from a high value of 100 kt to a low value of 12.5 kt. For each case, the wake is characterized at equivalent dimensionless ages, and the wake-induced hazard produced on a follower fixed-wing reference aircraft is quantified using the rolling moment coefficient (RMC) metric. At low airspeeds, the wake departs from the rolled-up wake configuration typical of fixed-wing aircraft and rotorcraft flying at high airspeed, exhibiting increased vortex spacing and higher turbulence levels. The inverse proportionality between flight speed and vortex circulation is also shown to break down; the RMC value saturates, and it also rapidly decreases downstream. In a second scenario, the rotorcraft is considered as a follower flying through a wake. For three airspeeds of the follower rotorcraft (100 kt, 50 kt, and 25 kt), simulations of the rotor flying quasi-steadily through rolled-up wake vortices are performed, and the resulting aerodynamic loads are quantified. The wake-induced pitching moment, which is the dominant perturbation, is found to scale with the airspeed of the follower rotorcraft. A pitching moment severity metric is evaluated against the numerical simulation: while it provides a useful first-order estimate, it fails to capture the observed speed dependence. Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Feb, 2026 Read the published version in CEAS Aeronautical Journal → Version 2 posted You are reading this latest preprint version Show more versions 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. 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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-6769712","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[{"code":1,"date":"2025-11-05 07:57:38","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":false,"email":"[email protected]","identity":"ceas-aeronautical-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"canj","sideBox":"Learn more about [CEAS Aeronautical Journal](http://link.springer.com/journal/13272)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/canj/default.aspx","title":"CEAS Aeronautical 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To address the existing gap in rotorcraft-specific studies, this paper first presents numerical simulations of the wake produced by a helicopter rotor in forward flight. The effect of the airspeed is investigated, from a high value of 100 kt to a low value of 12.5 kt.\nFor each case, the wake is characterized at equivalent dimensionless ages, and the wake-induced hazard produced on a follower fixed-wing reference aircraft is quantified using the rolling moment coefficient (RMC) metric. At low airspeeds, the wake departs from the rolled-up wake configuration typical of fixed-wing aircraft and rotorcraft flying at high airspeed, exhibiting increased vortex spacing and higher turbulence levels. The inverse proportionality between flight speed and vortex circulation is also shown to break down; the RMC value saturates, and it also rapidly decreases downstream.\nIn a second scenario, the rotorcraft is considered as a follower flying through a wake. 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