CFD analysis of an oscillating wing at various reduced frequencies

Abstract

SUMMARYThe effect of various reduced frequencies has been examined for an oscillating aspect ratio 10 NACA 0015 wing. An unsteady, compressible three-dimensional (3D) Navier-Stokes code based on Beam and Warming algorithm with the Baldwin-Lomax turbulence model has been used. The code is validated for the study against published experimental data. The 3D unsteady flow field is simulated for reduced frequency values of 0.1, 0.2 and 0.3 for a fixed mean angle of attack position and fixed amplitude. The type of motion is sinusoidal harmonic. The force coefficients, pressure distributions and flow visualization show that at the given conditions the flow remains attached to the wing surface even at high angles of attack with no clear separation or typical light-to-deep category of dynamic stall. Increased magnitude of hysteresis and higher gradients are seen at higher reduced frequencies. The 3D effects are even found at midspan locations. In addition, the rate of decrease in lift near the wing tips compared with the wing root is not much like in the static cases.

Systematic reduced order model development of a pitching NACA0012 airfoil

“…2.5 � 10 -5 2.33 � 10 -3 0.011 0.003 0.0001 5 � 10 - 5 4.67 � 10 -3 0.011 0.002 0.0001 1 � 10 - 4 9.33 � 10 -3 0.011 0.002 0.0001…”

“…Quick computation of these aerodynamic forces is required for predicting the external forces acting on these bodies in sub real-time for use in both controls and software and hardware in the loop applications. Computational fluid dynamics (CFD) simulations can predict the transient forces and moments; [1][2][3][4][5][6] however, these simulations cannot be conducted in real time with today's technology. Thus, the need to create reduced order models (ROMs) from the CFD simulation results is desired.…”

“…Many CFD studies have also been conducted to model and better understand the phenomena of the pitching airfoil aerodynamics. These CFD studies, ranging from unsteady Reynolds-Averaged Navier-Stokes simulation (URANS) [1][2][3][4][5] to direct numerical simulation (DNS) 6 approaches, were able to reproduce experimental data and provide physical insight into the flow characteristics that cause the transient aerodynamic effects. These CFD methods correlated well with experimental data but had significantly long run times.…”