Zonal improved delayed detached-Eddy simulation of vortex generator jets at high Reynolds numbers for aeronautical flows

2013 ◽  
Vol 4 (2) ◽  
pp. 203-222 ◽  
Author(s):  
S. Mahmood ◽  
R. Radespiel
Keyword(s):  
Vortex Generator ◽  
Reynolds Numbers ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
High Reynolds Numbers ◽  
Delayed Detached Eddy Simulation ◽  
Vortex Generator Jets ◽  
High Reynolds

Detached-Eddy Simulations and Reynolds-Averaged Navier-Stokes Simulations of Delta Wing Vortical Flowfields

2002 ◽  
Vol 124 (4) ◽  
pp. 924-932 ◽  
Author(s):  
Scott Morton ◽  
James Forsythe ◽  
Anthony Mitchell ◽  
David Hajek
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Fighter Aircraft ◽  
Eddy Simulation ◽  
Reynolds Averaged Navier Stokes ◽  
High Reynolds

An understanding of vortical structures and vortex breakdown is essential for the development of highly maneuverable vehicles and high angle of attack flight. This is primarily due to the physical limits these phenomena impose on aircraft and missiles at extreme flight conditions. Demands for more maneuverable air vehicles have pushed the limits of current CFD methods in the high Reynolds number regime. Simulation methods must be able to accurately describe the unsteady, vortical flowfields associated with fighter aircraft at Reynolds numbers more representative of full-scale vehicles. It is the goal of this paper to demonstrate the ability of detached-eddy Simulation (DES), a hybrid Reynolds-averaged Navier-Stokes (RANS)/large-eddy Simulation (LES) method, to accurately predict vortex breakdown at Reynolds numbers above 1×106. Detailed experiments performed at Onera are used to compare simulations utilizing both RANS and DES turbulence models.

Optimizing Jets for Active Control of Wake Refinement for Ground Vehicles

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Domenic L. Barsotti ◽  
Eduardo A. Divo ◽  
Sandra K. S. Boetcher
Keyword(s):  
Rear Surface ◽  
Reynolds Numbers ◽  
Special Focus ◽  
Detached Eddy Simulation ◽  
Ground Vehicles ◽  
Slant Angle ◽  
Eddy Simulation ◽  
Turbulent Coherent Structures ◽  
Delayed Detached Eddy Simulation ◽  
Ahmed Body

The present study investigates active drag reduction of an Ahmed body with a rear slant angle of 25 deg. The drag is reduced by implementing slot jets on the rear slant and rear surface of the Ahmed body. Transient numerical experiments were conducted using the improved delayed detached eddy simulation (IDDES) turbulence model. Jet velocity, position, size, and angle were parametrically varied, and time-averaged drag coefficients for various jet configurations were calculated. Reynolds numbers based on the length of the Ahmed body were varied, but special focus was given to the high-drag case when Re = 1.4 × 106. It was found that by using slot jets at the rear and rear slant, the drag coefficient was reduced by 22%. In order to investigate the physical mechanisms for the reduction in drag, proper orthogonal decomposition (POD) was used to visualize the turbulent coherent structures in the near wake of the Ahmed body.

scholarly journals Simulation of transonic buffet with an automated zonal DES approach

2020 ◽  
Vol 11 (4) ◽  
pp. 1025-1036
Author(s):  
Maximilian Ehrle ◽  
Andreas Waldmann ◽  
Thorsten Lutz ◽  
Ewald Krämer
Keyword(s):  
Three Dimensional ◽  
Reynolds Numbers ◽  
Research Model ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Shock Motion ◽  
Convection Speed ◽  
Transonic Buffet ◽  
Simulation Time

Abstract A study of transonic buffet on the NASA Common Research Model at flight Reynolds numbers is presented. The ability of two different hybrid RANS/LES models as well as the URANS approach for resolving three-dimensional buffet motion was evaluated by means of spectral analysis. Automated Zonal DES and URANS simulations show similar results in terms of buffet frequency and spanwise propagation of buffet cells, whereas the Delayed Detached Eddy Simulation results indicate a strong interaction between flow separation and shock motion. The extracted characteristic frequencies which are associated with transonic buffet are located in a range of Sr = 0.2–0.65 for URANS and AZDES and are therefore in accordance with findings from related recent research. Furthermore, the simulation time series were investigated and a structure of spanwise moving buffet cells with varying convection speed and wavelength could be observed.

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