03.4 - Applied Aerodynamics

THREE-DIMENSIONAL FLOW STRUCTURES OVER A LOW-ASPECT-RATIO PLUNGING WING

B. Anilir¹, D.F. Kurtulus¹, M.F. Platzer, University of California, Davis, United States; ¹Middle East Technical University, Turkey

The objective of this study is to numerically investigate the three-dimensional flow structures over a sinu- soidally plunging low-aspect-ratio NACA0012 wing (sAR = 1). The flow is analyzed by solving the URANS equations combined with the SST γ − Reθ model to capture transitional effects across various Reynolds num- bers (Re = 5 × 103 − 6 × 104) and nondimensional plunge velocities (vp = 1.05 − 3.14). The results show that while mean thrust coefficient scales directly with vp, propulsive efficiency behaves inversely. Interestingly, at higher frequencies, the 3D wing becomes more efficient than a 2D airfoil because tip-vortex-induced spanwise flow delays local dynamic stall over the mid-span. Furthermore, while 2D airfoils exhibit deflected wakes at high plunge velocities, the 3D finite wing maintains a symmetric reverse Karman vortex street across all conditions due to the symmetric circulation of its interconnected vortex loops and tip vortex.

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DOI: 10.71945/icas2026_0916