Unsteady aerodynamics over NACA0005 airfoil for ultra-low Reynolds numbers

Kouser T., KURTULUŞ D. F., Aliyu A., Goli S., Alhems L. M., IMRAN I. H., ...Daha Fazla

IEEE Access, cilt.12, ss.83658-83674, 2024 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 12
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1109/access.2024.3413153
  • Dergi Adı: IEEE Access
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Sayfa Sayıları: ss.83658-83674
  • Anahtar Kelimeler: Airfoil, critical angle, flow modes, k-mode, low reynolds number, NACA0005
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Numerical simulation for a two-dimensional NACA0005 is performed for angle of attack α = 0° − 15° in present study. The Reynolds numbers 1000, 2000 and 5000 are considered. Simulations show that the flow fields can be classified due to characteristics of vortex shedding based on Reynolds number and angle of attack. Furthermore, this study reveals that in case of the thinner airfoils, several modes (Mode I, Mode II, Mode III) are present at same angle of attack for varying Reynolds number. Maximum lift to drag ratio is found at Reynolds number 5000 and angle of attack 6° as well as gradual stall is observed. Onset of oscillations to determine critical angles of attack are reported for NACA0005 with the dominant frequencies. A subcategory of mode III termed as mode IIIa/c, and recently reported mode 4i is also observed in present study. A new mode termed as k-mode is observed for higher angles of attack at Re = 5000. In addition, numerical simulations of two-dimensional periodic flows around NACA0005 profile at Reynolds number Re = 5000 demonstrate that unsteady periodic flows reach different saturation states at angles of attack of 10° − 15°. The coexisting periodic states and period-doubling (with higher and lower intensities) in this range, indicate that the wake undergoes substantial changes from the von-Kármán vortex street.