LES of Compressible Wall-Bounded Flows

El‐Askary, W. A.; Schröeder, Wolfgang; Meinke, Matthias

doi:10.2514/6.2003-3554

Cited by 50 publications

(22 citation statements)

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“…The LES formulation is based on the monotone integrated LES (MILES) approach [9] modeling the impact of the subgrid scales by numerical dissipation. A detailed description of the fundamental LES solver is given by Meinke et al [10] and its convincing solution quality for fully turbulent sub-and supersonic §ows is discussed by Alkishriwi et al [11] and El-Askary et al [12]. The RANS part is based on the same overall discretization schemes and a one-equation turbulence model of Spalart and Allmaras [13] to close the time-averaged equations.…”

Section: Flow Solvermentioning

confidence: 99%

Combined experimental and numerical investigation of a transonic space launcher wake

Scharnowski

Statnikov

Meinke

et al. 2015

Progress in Flight Physics – Volume 7

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Combined experimental und numerical investigations of the turbulent wake of a generic space launcher at transonic free stream conditions (Ma ∞ = 0.7 and Re D = 1.0 · 10 6 ) are performed to gain a better understanding of intricate phenomena of the wake §ow physics and to validate new methods for its analysis. The experiments are conducted at the Bundeswehr University Munich using a high-repetition-rate particle image velocimetry (PIV) system, while the numerical investigation is performed by the Institute of Aerodynamics of RWTH Aachen University using a zonal Reynolds-averaged NavierStokes (RANS) / large-eddy simulation (LES) approach. After a characterization of the wake §ow topology, two applied methodologies are compared to each other with respect to the spatial and temporal resolution stressing their strengths and shortcomings. It is shown that both methods are well suitable for the prediction of the mean and instantaneous values of the turbulent velocity ¦eld, whereas for a reliable statistical analysis of the velocity §uctuations, the PIV approach is more appropriate due to the computational time limitations of the LES. On the other hand, the high spatial and temporal resolution of the LES allows for an accurate detection of relevant coherent structures as well as tracking their motion in time without any signi¦cant arti¦cial vortex agglomeration that can be critical in the case of PIV. Furthermore, the in §uence of di¨erent model assumptions, e. g., the level of incoming turbulence and model vibrations, is discussed in order to emphasize the importance of a side-by-side combination of both investigation techniques.

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Section: Flow Solvermentioning

confidence: 99%

Combined experimental and numerical investigation of a transonic space launcher wake

Scharnowski

Statnikov

Meinke

et al. 2015

Progress in Flight Physics – Volume 7

View full text Add to dashboard Cite

show abstract

“…The LES formulation is based on the monotone integrated LES (MILES) approach [18] modeling the impact of the subgrid scales by numerical dissipation. A detailed description of the fundamental LES solver is given by Meinke et al [19] and its convincing solution quality for fully turbulent sub-and supersonic §ows is discussed by Alkishriwi et al [20] and El-Askary et al [21]. The RANS part is based on the same overall discretization schemes and a one-equation turbulence model of Spalart and Almaras [22] to close the time-averaged equations.…”

Section: Flow Solvermentioning

confidence: 99%

Experimental and numerical investigation of the turbulent wake flow of a generic space launcher configuration

Statnikov

Saile

Meiss

et al. 2015

Progress in Flight Physics – Volume 7

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The turbulent wake of a generic space launcher at cold hypersonic freestream conditions is investigated experimentally and numerically to gain detailed insight into the intricate base §ow phenomena of space vehicles at upper stages of the §ight trajectory. The experiments are done at Ma ∞ = 6 and Re D = 1.7 · 10 6 m −1 by the German Aerospace Center (DLR) and the corresponding computations are performed by the Institute of Aerodynamics Aachen using a zonal Reynolds-averaged Navier Stokes / Large-Eddy Simulation (RANS/LES) approach. Two di¨erent aft-body geometries consisting of a blunt base and an attached cylindrical nozzle dummy are considered. It is found that the wind tunnel model support attached to the upper side of the main body has a nonnegligible impact on the wake along the whole circumference, albeit on the opposite side, the e¨ects are minimal compared to an axisymmetric con¦guration. In the blunt-base case, the turbulent supersonic boundary layer undergoes a strong aftexpansion on the model shoulder leading to the formation of a con¦ned low-pressure (p/p ∞ ≈ 0.2) recirculation region. Adding a nozzle dummy causes the shear layer to reattach on the its wall at x/D ∼ 0.6 and the base pressure level to increase (p/p ∞ ≈ 0.25) compared to the blunt-base case. For both con¦gurations, the pressure §uctuations on the base wall feature dominant frequencies at Sr D ≈ 0.05 and Sr D ≈ 0.2 0.27, but are of small amplitudes (p rms /p ∞ = 0.02 0.025) compared to the main body boundary layer. For the nozzle dummy con¦guration, when moving downstream along the nozzle extension, the wall pressure is increasingly in §uenced by the reattaching shear layer and the periodic low-frequency behavior

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“…The accuracy of its solutions in fully turbulent §ows is discussed in [18 20]. The solution algorithm has also shown convincing results in supersonic §ows involving shock boundary layer interactions [21].…”

Section: Methodsmentioning

confidence: 99%

“…To avoid this computationally costly approach, an independent boundary layer simulation is performed using the rescaling method proposed by El-Askary et al [21], which is based on Lund et al£s [22] approach considering compressibility.…”

Section: Boundary Conditions and Computational Meshmentioning

confidence: 99%

“…At the lower wall of the ¦lm-cooling simulation domain adiabatic no-slip boundary conditions are imposed, at the exit all variables are extrapolated. To avoid any spurious oscillations, a sponge layer is used at the exit and at the top of the boundary-layer domain where the §ow variables are driven to the desired target variables [21]. At the slot, a laminar supersonic cooling §ow is prescribed.…”

Section: Boundary Conditions and Computational Meshmentioning

confidence: 99%

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Large-eddy simulation of high mach number film cooling with shock-wave interaction

Konôpka

Meinke

Schröder

2013

Progress in Flight Physics

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The impact of shock waves on supersonic cooling ¦lms is studied using large-eddy simulations (LES). A laminar cooling ¦lm is injected through a slot at a Mach number Ma i = 1.8 into a fully turbulent boundary layer at a freestream Mach number Ma ∞ = 2.44. The cooling ¦lm is disturbed by oblique shock waves at de §ection angles of 5 • and 8 • at two downstream positions of the slot. At shock impingement close to the slot, i. e., within the potential-core region, at a §ow de §ection of 5 • , a cooling e¨ectiveness decrease of 33% occurs downstream of the separation bubble compared to a con¦guration without shock impingement. If the same shock impinges further downstream upon the boundary-layer region, the decrease is only 17%. The stronger 8 degree shock wave at the further downstream impingement position leads to a maximum decrease of 33%.

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LES of Compressible Wall-Bounded Flows

Cited by 50 publications

References 0 publications

Combined experimental and numerical investigation of a transonic space launcher wake

Combined experimental and numerical investigation of a transonic space launcher wake

Experimental and numerical investigation of the turbulent wake flow of a generic space launcher configuration

Large-eddy simulation of high mach number film cooling with shock-wave interaction

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