Unsteady Aerodynamics of an Airfoil/Flap Combination on a Helicopter Rotor Using Computational Fluid Dynamics and Approximate Methods

作者：Liu Li^*; Padthe Ashwani K; Friedmann Peretz P; Quon Eliot; Smith Marilyn J

来源：Journal of the American Helicopter Society, 2011, 56(3): 032003.

DOI：10.4050/JAHS.56.032003

The ability tomodel accurately and efficiently unsteady aerodynamic effects for actively controlled trailing-edge flaps (ACFs) is crucial for practical application of such systems for vibration and noise reduction as well as performance enhancement. Two-dimensional unsteady airloads due to oscillating flapmotion are calculated and compared using various computational fluid dynamics (CFD) codes and a CFD-based reduced-order model (ROM). This ROM is based on the rational function approximations approach, which yields a state-space, time-domain aerodynamic model suitable for incorporation into comprehensive rotorcraft simulation codes. The accuracy of this model is demonstrated across a practical range of unsteady flow conditions encountered by active flaps. Two Reynolds-averaged Navier-Stokes solvers (CFD++ and OVERFLOW) are employed in conjunction with various turbulence models, including large eddy simulation based models, so as to examine code independence. Flow physics associated with three-dimensional effects, flap hinge gap, as well as compressibility effects are also examined.

• 出版日期2011-7