Aircraft wake vortices in stably stratified and weakly turbulent atmospheres: simulation and modeling

This study investigates the influence, on aircraft wake vortex behavior, of atmospheres that are stably stratified (neutral to very strong) and weakly turbulent, by means of large-eddy simulations at very high Reynolds number and on relatively fine grids. The atmospheric fields are first generated using large-eddy simulations of forced and stratified turbulence reaching a statistically stationary state. The obtained fields are shown to be realistic and consistent with the literature. A pair of counter-rotating vortices, with relatively tight cores, is then put in the obtained fields and evolved. The evolution of the wake vortex topology, transport, and decay is analyzed in depth by measuring the wake vortex characteristics in all cross planes. The vortex transport and deformation are related to the stratification and turbulence levels. Stratification combined with weak turbulence is seen to strongly affect the Crow instability development. Different decay mechanisms are identified, related to the interactions with the turbulence, the turbulent baroclinic vorticity, and/or between the vortices themselves. Finally, improved simplified models of vortex altitude evolution and of vortex decay (with two phases) are proposed and calibrated on the present results. They yield good agreement with the large-eddy simulation results and are usefully integrated in our operational models. Read More: http://arc.aiaa.org/doi/abs/10.2514/1.J051742

[1]  Grégoire Winckelmans,et al.  Investigation of multiscale subgrid models for LES of instabilities and turbulence in wake vortex systems , 2007 .

[2]  Laurent Bricteux,et al.  LES of aircraft wake vortices evolving in a stably stratified and weakly turbulent atmosphere , 2010 .

[3]  D W Moore,et al.  Finite Amplitude Waves on Aircraft Trailing Vortices , 1972 .

[4]  Frank Holzäpfel,et al.  Probabilistic Two-Phase Wake Vortex Decay and Transport Model , 2003 .

[5]  George F. Switzer,et al.  Numerical Study of Wake Vortex Behavior in Turbulent Domains with Ambient Stratification , 2000 .

[6]  Hervé Jeanmart,et al.  Investigation of eddy-viscosity models modified using discrete filters : A simplified regularized variational multiscale model and an enhanced field model , 2007 .

[7]  Robert E. Robins,et al.  Numerical Simulations of Three-Dimensional Trailing Vortex Evolution , 1997 .

[8]  Laurent Bricteux,et al.  A multiscale subgrid model for both free vortex flows and wall-bounded flows , 2009 .

[9]  Thierry Poinsot,et al.  Wave propagation in vortices and vortex bursting , 2005 .

[10]  J. Rottman,et al.  Short-wavelength instability and decay of a vortex pair in a stratified fluid , 2006, Journal of Fluid Mechanics.

[11]  Fred H. Proctor,et al.  Within Homogeneous Turbulence: Crow Instability Large Eddy Simulation of Aircraft Wake Vortices , 2000 .

[12]  R. S. Scorer,et al.  Contrails and aircraft downwash , 1970, Journal of Fluid Mechanics.

[13]  Charles H. K. Williamson,et al.  Cooperative elliptic instability of a vortex pair , 1998, Journal of Fluid Mechanics.

[14]  Philippe R. Spalart,et al.  AIRPLANE TRAILING VORTICES , 1998 .

[15]  Philip Geoffrey Saffman.  The Motion of a Vortex Pair in a Stratified Atmosphere , 1972 .

[16]  Thomas Gerz,et al.  The turbulent decay of trailing vortex pairs in stably stratified environments , 2001 .

[17]  Robert E. Robins,et al.  Short-Scale Instabilities in Trailing Wake Vortices in a Stratified Fluid , 2000 .

[18]  Turgut Sarpkaya,et al.  New Model for Vortex Decay in the Atmosphere , 2000 .

[19]  E. Lindborg,et al.  The energy cascade in a strongly stratified fluid , 2006, Journal of Fluid Mechanics.

[20]  A. J. Bilanin,et al.  Turbulent Trailing Vortices in Stratified Fluids , 1980 .

[21]  David C. Fritts,et al.  Dynamics of counter-rotating vortex pairs in stratified and sheared environments , 1998, Journal of Fluid Mechanics.

[22]  George F. Switzer.  Wake Vortex Prediction Models for Decay and Transport Within Stratified Environments , 2002 .

[23]  Laboratory Measurements of the Circulation Decay of Vortices Generated From a Lifting Wing , 2011 .

[24]  J. Williamson.  Low-storage Runge-Kutta schemes , 1980 .

[25]  Robert E. Robins,et al.  Numerical simulation of three-dimensional trailing vortex evolution in stratified fluid , 1998 .

[26]  Donald B. Bliss,et al.  The instability of short waves on a vortex ring , 1974, Journal of Fluid Mechanics.

[27]  J. Smagorinsky,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS , 1963 .

[28]  W. S. Lewellen,et al.  Large-Eddy Simulations and Lidar Measurements of Vortex-Pair Breakup in Aircraft Wakes , 1998 .

[29]  Laurent Bricteux,et al.  Large Eddy Simulations of aircraft wake vortices in a stably stratified atmosphere , 2009 .

[30]  Laurent Bricteux,et al.  Scale dependence and asymptotic very high Reynolds number spectral behavior of multiscale subgrid models , 2009 .

[31]  Takashi Misaka,et al.  Wake-Vortex Topology, Circulation, and Turbulent Exchange Processes , 2010 .

[32]  Michael L. Waite.  Stratified turbulence at the buoyancy scale , 2011 .

[33]  Thomas Gerz,et al.  Commercial aircraft wake vortices , 2002 .

[34]  Fred H. Proctor,et al.  Three-Phased Wake Vortex Decay , 2010 .

[35]  P. Bartello,et al.  Stratified turbulence dominated by vortical motion , 2004, Journal of Fluid Mechanics.

[36]  J. Riley,et al.  Fluid Motions in the Presence of Strong Stable Stratification , 2000 .

[37]  J. Andrzej Domaradzki,et al.  Similarity scaling and vorticity structure in high-Reynolds-number stably stratified turbulent wakes , 2011, Journal of Fluid Mechanics.

[38]  C. Williamson,et al.  Experiments on long-wavelength instability and reconnection of a vortex pair , 2011 .

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

[40]  Turbulent Vortices in Stratified Fluids , 1980 .

[41]  W. S. Lewellen,et al.  Large-eddy simulations of the vortex-pair breakup in aircraft wakes , 1996 .

[42]  Turgut Sarpkaya,et al.  Trailing vortices in homogeneous and density-stratified media , 1983, Journal of Fluid Mechanics.

[43]  P. Bartello,et al.  Stratified turbulence generated by internal gravity waves , 2005, Journal of Fluid Mechanics.

[44]  Jinhee Jeong,et al.  On the identification of a vortex , 1995, Journal of Fluid Mechanics.

[45]  J. Riley,et al.  Dynamics of turbulence strongly influenced by buoyancy , 2003 .

[46]  Steven A. Orszag,et al.  Local energy flux and subgrid-scale statistics in three-dimensional turbulence , 1998, Journal of Fluid Mechanics.

[47]  J. Chomaz,et al.  Scaling analysis and simulation of strongly stratified turbulent flows , 2007, Journal of Fluid Mechanics.

[48]  F. M. Hill,et al.  A numerical study of the descent of a vortex pair in a stably stratified atmosphere , 1975, Journal of Fluid Mechanics.

[49]  Fred H. Proctor,et al.  Large Eddy Simulation of Aircraft Wake Vortices Within Homogeneous Turbulence: Crow Instability , 2000 .

[50]  J. Herring,et al.  Numerical experiments in forced stably stratified turbulence , 1989, Journal of Fluid Mechanics.

[51]  David C. Fritts,et al.  Direct numerical simulations of the Crow instability and subsequent vortex reconnection in a stratified fluid , 2001, Journal of Fluid Mechanics.

[52]  F. Holzäpfel,et al.  Wing-tip vortices, turbulence, and the distribution of emissions , 1999 .

[53]  T. Gerz,et al.  Two-dimensional wake vortex physics in the stably stratified atmosphere , 1999 .

[54]  Laurent Bricteux,et al.  The WAKE4D simulation platform for predicting aircraft wake vortex transport and decay : Description and examples of application , 2010 .

[55]  Philippe R. Spalart,et al.  On the motion of laminar wing wakes in a stratified fluid , 1996 .