Optimization of Aircraft Wake Alleviation Schemes through an Evolution Strategy

We investigate schemes to accelerate the decay of aircraft trailing vortices. These structures are susceptible to several instabilities that lead to their eventual destruction.We employ an Evolution Strategy to design a lift distribution and a lift perturbation scheme that minimize the wake hazard as proposed in [6]. The performance of a scheme is measured as the reduction of the mean rolling moment that would be induced on a following aircraft; it is computed by means of a Direct Numerical Simulation using a parallel vortex particle code. We find a configuration and a perturbation scheme characterized by an intermediate wavelength λ ∼ 4.64, necessary to trigger medium wavelength instabilities between tail and flap vortices and subsequently amplify long wavelength modes.

[1]  George Miller,et al.  Active-Control System for Breakup of Airplane Trailing Vortices , 2001 .

[2]  Alessandro Curioni,et al.  Billion vortex particle direct numerical simulations of aircraft wakes , 2008 .

[3]  J. Monaghan,et al.  Extrapolating B splines for interpolation , 1985 .

[4]  S. Crow.  Stability theory for a pair of trailing vortices , 1970 .

[5]  Petros Koumoutsakos,et al.  Vortex Methods: Theory and Practice , 2000 .

[6]  Petros Koumoutsakos,et al.  Reducing the Time Complexity of the Derandomized Evolution Strategy with Covariance Matrix Adaptation (CMA-ES) , 2003, Evolutionary Computation.

[7]  Petros Koumoutsakos,et al.  Inviscid Axisymmetrization of an Elliptical Vortex , 1997 .

[8]  Thomas J. R. Hughes,et al.  Encyclopedia of computational mechanics , 2004 .

[9]  Eike Stumpf,et al.  Study of Four-Vortex Aircraft Wakes and Layout of Corresponding Aircraft Configurations , 2005 .

[10]  Stefan Kern,et al.  Bioinspired optimization algorithms for the design of anguilliform swimmers , 2007 .

[11]  Omer Savas,et al.  Experimental study of the instability of unequal-strength counter-rotating vortex pairs , 2003, Journal of Fluid Mechanics.

[12]  Christopher R. Anderson,et al.  On Vortex Methods , 1985 .

[13]  Grégoire Winckelmans,et al.  Vortex methods and their application to trailing wake vortex simulations , 2005 .

[14]  Georges-Henri Cottet,et al.  Artificial Viscosity Models for Vortex and Particle Methods , 1996 .

[15]  J. D. Crouch.  Instability and transient growth for two trailing-vortex pairs , 1997 .

[16]  P. R. Owen,et al.  The Decay of a Turbulent Trailing Vortex , 1970 .

[17]  Petros Koumoutsakos,et al.  A Fourier-based elliptic solver for vortical flows with periodic and unbounded directions , 2010, J. Comput. Phys..