Skip to main content
European Commission logo print header
Inhalt archiviert am 2022-12-23

Theoretical investigations of the influence of the aircraft engine jet on the wake vortex formation

Ziel

The objectives of the project are:
To investigate the effects of an engine parameters (bypass ratio, long or short duct) on the process of jet-vortex wake formation behind passenger aircraft;
To investigate the effects of engine placement and power setting on the process of jet-vortex wake formation behind passenger aircraft;
To investigate the effects of atmospheric conditions (turbulence level, stratification) on the process of jet-vortex merging behind an aircraft with accounting for the jet buoyancy;
To determine the distributions of pressure, density, temperature and combustion products in a jet-vortex wake behind an aircraft.

There are some experimental data (including flight tests), which permit one to conclude that the engine jets influence the aircraft wake significantly. The type of engines, their quantity and placement on an airplane are the important factors influencing the process of jet-vortex wake formation behind an aircraft. The atmospheric conditions (level of turbulence, stratification) are also important parameters. The obtaining of the experimental data is limited by the high cost of experimental researches and impossibility of simulating flight conditions in wind tunnels. It is supposed to study the effect of engine jets on vortex wake formation theoretically using the existing experimental data.
From the previous researches it is known, that the characteristic size of the jet diffusion region is about 150 - 350 diameters of the nozzle. The coherent multiple vortex-core structure is formed behind an airplane at a distance of about 10-15 wingspans. The typical ratio of engine nozzle diameter to wingspan of a modern airplane is 1/30. According to this the main processes of interaction of jets with a vortex wake will occur in a region at distances of up to 10-15 wingspans behind an airplane.
The computational domain extends downstream of an aircraft to 10-15 wingspans and is divided into two sub domains, with different problems being considered in each of them.
In the near wake region (about one wingspan):
calculation of lift and drag distribution and the beginning of vortex formation from the trailing vortex sheet (panel methods and 2D N-S code), calculation of the jet trajectories and variation of jet parameters over a trajectory (using the laws of conservation of mass and momentum in the sections normal to the jet trajectory);
study of the power-plant operation effect on the near-wake formation by solving an unsteady aircraft flow problem using the discrete vortex method
In the region of merging the vortex wake and engine jets and forming the coherent vortex pair:
calculation of the interaction between jets and vortex wake (incompressible fluid, Reynolds-averaged NS equations), determination of the influence of small-scale turbulence generated by engine jets on vorticity dissipation;
creation of the mathematical model of the far jet-vortex wake allowing the processes of wake formation and propagation to be accounted for together with the effects of wind (including both wind profile and direction), atmospheric turbulence, ground proximity and other factors;
As a result of the given research, the distributions of vorticity, pressure, temperature and products of combustion in a section at a distance of 10-15 wingspans behind an aircraft will be obtained depending on the types of an aircraft and engine, flight and atmospheric conditions.

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

Data not available

Koordinator

DaimlerChrysler Aerospace Airbus
EU-Beitrag
Keine Daten
Adresse
Hünefeldstra?e 1 - 5
28199 Bremen
Deutschland

Auf der Karte ansehen

Gesamtkosten
Keine Daten

Beteiligte (6)