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- Theoretical and Numerical Analysis of Oscillating Airfoil Including Viscous EffectsPublication . Torres, George Lucas; Camacho, Emanuel; Marques, Flávio D.; Silva, AndréUnsteady airfoils are the way to explore new aerodynamic phenomena which do not appear in ordinarily aeronautical applications. At lower Reynolds numbers, unsteady flow can make way to newer technologies to be implemented in areas such as extraterrestrial exploration. In the present work, the Theodorsen classical unsteady theory and a viscous extension to this model are implemented. Results from those computations are then compared with high fidelity CFD simulations using laminar and turbulent assumptions. Results obtained by using the viscous model indicate a good agreement with CFD data, although there are still some discrepancies at the trailing edge.
- Simulations of a Plunging Airfoil Undergoing Unequal Ascending and Descending Velocities at Low Reynolds NumbersPublication . Torres, George L. S.; Camacho, Emanuel; Marques, Flávio D.; Silva, AndréDynamic stall is an effect frequently seen in nature and rotary wings where flow separation induces strong force oscillations. In order to simulate such phenomena, reduced-order models (ROMs) such as the LESP-modulated discrete-vortex method (LDVM) are often used whose applicability at low Reynolds number is discussed here. CFD computations with the SST were conducted to obtain the critical leading-edge suction parameter (LESP) by analyzing the skin friction coefficient distribution for the Reynolds number tested of 1,500. Results explore both symmetrical and asymmetrical plunging of a NACA0012 airfoil following a triangular velocity profile, indicating a good agreement between experimental, CFD, and LDVM computations, which makes the latter, a very efficient and adequate method to study wake configurations of oscillating airfoils at low Reynolds numbers.