Validation of Aerodynamic and Aeroacoustic Simulations of Contra-Rotating Open Rotors at Low-Speed Flight Conditions

Stürmer, Arne; Akkermans, R.A.D.

doi:10.2514/6.2014-3133

Cited by 15 publications

(16 citation statements)

References 13 publications

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“…All CFD simulations are performed utilizing the DLR TAU-Code for both the steady RANS and the uRANS computations. For the latter, much know-how was transferred from a process chain that has already been successfully applied in a number of recent propeller and CROR investigations [1,[9][10][11][12][13][14], where validation with wind tunnel test data has shown high-quality engine performance predictions for various isolated and installed configurations is achievable, with deviations of less than 1% to the experimental values.…”

Section: Computational Strategymentioning

confidence: 99%

“…Total mesh size for the isolated UHBR configuration as shown in Figure 4a ranges from 28.4 × 10 6 nodes for the coarse to 200 × 10 6 nodes for the fine mesh level, with further grid details listed in Table 2. In addition to ensuring an adequate resolution of boundary layers (including the laminar sublayer) on all surfaces of the engine, with a dimensionless wall distance of y+ = 1 achieved throughout, a particular focus of the mesh generation was to ensure the transfer of the fan blade wakes into the OGV mesh block is possible in the uRANS simulation with minimal interpolation losses [12]. Thus, the overlap region of the these two grids is meshed in a way that ensures an identical, axially-aligned cell orientation, and a matching number and uniform spacing of the cells for the annulus on the rear Chimera boundary of the fan block and the forward Chimera boundary of the OGV block.…”

Section: Mesh Generationmentioning

confidence: 99%

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DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Stuermer¹

2019

Aerospace

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In the context of an increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards larger bypass ratio engine designs, with Ultra-High Bypass Ratio (UHBR) engines becoming a likely power plant option for future commercial transport aircraft. These engines promise low specific fuel consumption at the engine level, but the resulting size of the nacelle poses challenges in terms of the installation on the airframe. Thus, their integration on an aircraft requires careful consideration of complex engine–airframe interactions impacting performance, aeroelastics and aeroacoustics on both the airframe and the engine sides. As a partner in the EU funded Clean Sky 2 project ASPIRE, the DLR Institute of Aerodynamics and Flow Technology is contributing to an investigation of numerical analysis approaches, which draws on a generic representative UHBR engine configuration specifically designed in the frame of the project. In the present paper, project results are discussed, which aimed at demonstrating the suitability and accuracy of an unsteady RANS-based engine modeling approach in the context of external aerodynamics focused CFD simulations with the DLR TAU-Code. For this high-fidelity approach with a geometrically fully modeled fan stage, an in-depth study on spatial and temporal resolution requirements was performed, and the results were compared with simpler methods using classical engine boundary conditions. The primary aim is to identify the capabilities and shortcomings of these modeling approaches, and to develop a best-practice for the uRANS simulations as well as determine the best application scenarios.

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Section: Computational Strategymentioning

confidence: 99%

Section: Mesh Generationmentioning

confidence: 99%

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Stuermer¹

2019

Aerospace

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“…As for delta wings, the boundary layer separates at the leading edge and rolls up in a spiral fashion [32][33][34]. This leading-edge vortex, present at highthrust condition [35,36], affects both the blade surface pressure distribution and the wall friction; a low-pressure area is observed on the wall underneath the vortex, and an attachment line delimits the vortex chordwise extension (see Fig. 4).…”

Section: Aerodynamic and Acoustic Characteristics Of Baseline Conmentioning

confidence: 99%

Influence of Torque Ratio on Counter-Rotating Open-Rotor Interaction Noise

Delattre

Falissard

2015

AIAA Journal

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This paper investigates the influence of the torque ratio, at constant total thrust, on the interaction noise of a generic counter-rotating open rotor in pusher configuration. It is shown that torque ratio has a small influence on the openrotor aerodynamic performance but a strong impact on interaction noise at takeoff condition. The noise source mechanisms are investigated in detail and linked with the characteristics of the front rotor blade-tip vortices. Tip vortex characteristics are detailed and compared with analytical vortex models. It is verified that torque ratio variation has no strong impact on the open-rotor aerodynamic performance at cruise condition.

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“…Ref. [39], is typical of highly swept propellers for high loads operating point at low speed and contributes to the radiated tonal 21,22 and broadband 40 noise. Contrarily to the cruise operating point, the flow is now highly three-dimensional due to the separation at the front and rear blade leading edges.…”

Section: Ivc Flow Topologymentioning

confidence: 99%