| 1. |
- Grosshans, H., et al.
(författare)
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Fuel jet mixing enhanced by intermittent injection
- 2013
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Ingår i: 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013. - Reston, Virigina : American Institute of Aeronautics and Astronautics. - 9781624101816
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Konferensbidrag (refereegranskat)abstract
- The paper considers the effects of intermittent injection of a fuel spray on the initial break-up and mixing of the fuel with the surrounding "ambient" fluid. The two fluids may have the same phase or different phases. The aim of the analysis is to describe the physical process and indicate the mechanisms that control the mixing under different flow conditions (time-dependent injection and its frequency relative to the time scales of the flow) and fluid properties (Schmidt number in the single phase case or the Weber number for liquid fuel case. The computations use Large Eddy Simulation (LES) for accounting for turbulence and either Volume Of Fluid (VOF) for the initial break-up and Lagrangian Particle Tracking (LPT) with droplet break-up model in the case of liquid droplets injected into the ambient gas. The results show that depending on the physical properties of the fuel and ambient gas, the initial break-up and turbulent mixing can be enhanced substantially with intermittent injection. Most of the mixing is driven by the suction of ambient fluid at the tail of the injected fuel (as was shown experimentally and in a one dimensional model by Musculus and co-workers).
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| 2. |
- Tomac, Maximillian, et al.
(författare)
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Calibration and verification of a γ - Reθt transition prediction method for airfoil computations
- 2013
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Ingår i: 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013. - 9781624101816
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Konferensbidrag (refereegranskat)abstract
- This paper deals with the implementation and verification of a γ - Reθt correlation based transition prediction method previously presented by Langtry et al. The two additional transport equations used for predicting transition and a novel set of equations for the production terms are implemented into the Computational Fluid Dynamics code Edge. The model predicts two-dimensional transition phenomena such as transition due to Tollmein-Schlichting instabilities, bypass transition and separation induced transition. The transition prediction model is calibrated to the well-known Ercoftac wind tunnel tests using an optimization program based on a direct search method available in Matlab. The model is tested with several non-calibrated cases comparable with industry standard airfoils (low speed, transonic) and wind tunnel experiments as well as the MSES code that uses a en method. The main part of this work was performed as part of the research project Aerodynamic Loads Estimation at Extremes of the Flight Envelope (ALEF) (Grant Agreement no: 211785), 7th EU framework program.
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| 3. |
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| 4. |
- Zhang, Mengmeng, et al.
(författare)
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Variable fidelity methods and surrogate modeling of critical loads on X-31 aircraft
- 2013
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Ingår i: 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013. - Reston, Virigina : American Institute of Aeronautics and Astronautics. - 9781624101816
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a method for effcient creation of the aerodynamic database for the X-31 experimental aircraft, from low fidelity (Euler) and high fidelity (RANS) CFD. The challenge is to obtain good data for extreme flight conditions. A co-Kriging interpolation model for aerodynamic moments, forces and span loads is used, with an additional decision support system (DSS) using Proper Orthogonal Decomposition for data reduction.
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