Investigation of Cross Flow in the Presence of a Laminar Separation Bubble

Andrew Frisch, Alek Cotnoir, David Borgmann, Shirzad Hosseinverdi, Hermann Fasel, Jesse C Little

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Cross-flow development is investigated in conditions suitable for the formation of laminar separation bubbles (LSBs) using a NACA 643 − 618 airfoil at a sweep angle of Γ = 45° and a chord wise Reynolds number of ReC = 600k. The dominant wavenumber of naturally developing stationary cross-flow is found at spanwise wavenumber of Kc = 550 for α = 0°. This is consistent with hydrodynamic stability calculations using parabolized stability equations. Discrete roughness elements are added to amplify the most unstable stationary cross-flow wavelength in the presence of an LSB (α = 0°), and also for a case of cross-flow dominated transition at α = −8°. Time resolved velocity measurements using constant temperature anemometry (CTA) were performed at several planes in the favorable to adverse pressure gradient region up to the point of laminar separation (x/c = 0.50). Spanwise measurements at x/c = 0.35 confirm the presence of stationary cross-flow vortices through the periodic nature of the boundary layer in the mean flow and RMS. Indication of travelling cross-flow is observed in regions of higher disturbances, close to the wall. Near the point of separation (x/c = 0.50), the spanwise coherent structures in the boundary layer contain characteristics of both traveling and stationary cross-flow.

Original languageEnglish (US)
Title of host publicationAIAA SciTech Forum and Exposition, 2024
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624107115
DOIs
StatePublished - 2024
EventAIAA SciTech Forum and Exposition, 2024 - Orlando, United States
Duration: Jan 8 2024Jan 12 2024

Publication series

NameAIAA SciTech Forum and Exposition, 2024

Conference

ConferenceAIAA SciTech Forum and Exposition, 2024
Country/TerritoryUnited States
CityOrlando
Period1/8/241/12/24

ASJC Scopus subject areas

  • Aerospace Engineering

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