Large-Eddy Simulations and Lidar Measurements of Vortex-Pair Breakup in Aircraft Wakes

Lewellen, D. C.; Lewellen, W. S.; Poole, L. R.; DeCoursey, Robert J.; Hansen, G.; Hostetler, C. A.; Kent, G. S.

doi:10.2514/2.535

Cited by 17 publications

(3 citation statements)

References 9 publications

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“…Thus, 3-D dynamical phenomena like the well-known Crow instability of the trailing vortices (Crow, 1970) lead to substantial variations along the flight direction, even if the environmental conditions are homogeneous in this direction, as exemplified by Lewellen et al (1998) and for conserved exhaust species, and by Lewellen and Lewellen (2001) and U2014 for contrails.…”

Section: Contrail Widthmentioning

confidence: 99%

Properties of young contrails – a parametrisation based on large-eddy simulations

Unterstraßer

2016

Atmos. Chem. Phys.

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Abstract. Contrail–cirrus is probably the largest climate forcing from aviation. The evolution of contrail–cirrus and its radiative impact depends not only on a multitude of atmospheric parameters, but also on the geometric and microphysical properties of the young contrails evolving into contrail–cirrus. The early evolution of contrails (t <  5 min) is dominated by an interplay of ice microphysics and wake vortex dynamics. Young contrails may undergo a fast vertical expansion due to a descent of the wake vortices and may lose a substantial fraction of their ice crystals due to adiabatic heating. The geometric depth H and total ice crystal number N of young contrails are highly variable and depend on many environmental and aircraft parameters. Both properties, H and N, affect the later properties of the evolving contrail–cirrus, as they control the extent of shear-induced spreading and sedimentation losses. In this study, we provide parametrisations of H and N after 5 min taking into account the effects of temperature, relative humidity, thermal stratification and aircraft type (mass, wing span, fuel burn). The parametrisations rely on a large data set of recent large-eddy simulations of young contrails. They are suited to be incorporated in larger-scale models in order to refine the present-day contrail initialisations by considering the processes that strongly affect the contrail evolution during the vortex phase.

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Section: Contrail Widthmentioning

confidence: 99%

Properties of young contrails – a parametrisation based on large-eddy simulations

Unterstraßer

2016

Atmos. Chem. Phys.

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“…LESs can model dynamics on a scale of several millions of grid points, for a few seconds to a few minutes of plume age, providing unmatched levels of accuracy at the cost of extremely high computational demand. For this reason, LESs are usually limited to case studies from which the data obtained can be used to derive and calibrate plume parametrisations for use in the lower fidelity methods [57].…”

Section: Large Eddy Simulations (Less)mentioning

confidence: 99%

Aircraft Emissions, Their Plume-Scale Effects, and the Spatio-Temporal Sensitivity of the Atmospheric Response: A Review

et al. 2022

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Non-CO2 aircraft emissions are responsible for the majority of aviation’s climate impact, however their precise effect is largely dependent on the environmental conditions of the ambient air in which they are released. Investigating the principal causes of this spatio-temporal sensitivity can bolster understanding of aviation-induced climate change, as well as offer potential mitigation solutions that can be implemented in the interim to low carbon flight regimes. This review paper covers the generation of emissions and their characteristic dispersion, air traffic distribution, local and global climate impact, and operational mitigation solutions, all aimed at improving scientific awareness of aviation’s non-CO2 climate impact.

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“…While two-dimensional simulations give many insights into the descent of the trailing vortices, they cannot capture the long-wave instability. Lewellen & Lewellen (1996) and Lewellen et al (1998) conducted three-dimensional large eddy simulations (LES) of aircraft wakes at conditions that mimic the realistic atmosphere. The long-wave instability leads to a series of vortex rings in their LES, which agree with the photographs taken from the ground.…”

Section: Introductionmentioning

confidence: 99%

Evolution of two counter-rotating vortices in a stratified turbulent environment

Bin

Yang

et al. 2022

J. Fluid Mech.

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We conduct direct numerical simulations and study the evolution of a pair of counter-rotating vortices in a stratified and turbulent environment beyond the first vortex linking (which is due to the Crow instability). The initial position of the two vortices is perpendicular to the direction of thermal stratification. We vary the Froude number, the background turbulence intensity and the Reynolds number, covering strong, weak and neutral stratification; low, moderate and high background turbulence; and low and moderate Reynolds numbers. We observe a second vortex linking in a weakly stratified environment for the first time. The second vortex linking is followed by turbulence bursts that lead to the rapid decay of the residual vortices after the first vortex linking, leading to a short-living vortex pair. This challenges the conventional view that residual vortices have a long life span, which is true only in an unstratified environment. In addition to the second vortex linking, we observe the following. First, strong background turbulence quickly breaks the two vortices. Second, the two vortices induce secondary and tertiary vortices and lose energy to gravitational waves in a strongly stratified ( $Fr\leqslant 0.7$ ) environment.

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Large-Eddy Simulations and Lidar Measurements of Vortex-Pair Breakup in Aircraft Wakes

Cited by 17 publications

References 9 publications

Properties of young contrails – a parametrisation based on large-eddy simulations

Properties of young contrails – a parametrisation based on large-eddy simulations

Aircraft Emissions, Their Plume-Scale Effects, and the Spatio-Temporal Sensitivity of the Atmospheric Response: A Review

Evolution of two counter-rotating vortices in a stratified turbulent environment

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