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355 results on '"Barakos, G."'

11. Rotor Computations with Active Gurney Flaps

Author

Woodgate, M. A., Pastrikakis, V. A., Barakos, G. N., Boersma, Bendiks Jan, Series editor, Fujii, Kozo, Series editor, Haase, Werner, Series editor, Leschziner, Michael A., Series editor, Periaux, Jacques, Series editor, Pirozzoli, Sergio, Series editor, Rizzi, Arthur, Series editor, Roux, Bernard, Series editor, Shokin, Yurii I., Series editor, Braza, Marianna, editor, Bottaro, Alessandro, editor, and Thompson, Mark, editor

Published
2016
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12. Evaluation of Scale-Adaptive Simulations for Transonic Cavity Flows

Author

Babu, S. V., Zografakis, G., Barakos, G. N., Boersma, Bendiks Jan, Series editor, Fujii, Kozo, Series editor, Haase, Werner, Series editor, Leschziner, Michael A., Series editor, Periaux, Jacques, Series editor, Pirozzoli, Sergio, Series editor, Rizzi, Arthur, Series editor, Roux, Bernard, Series editor, Shokin, Yurii I., Series editor, Girimaji, Sharath, editor, Peng, Shia-Hui, editor, and Schwamborn, Dieter, editor

Published
2015
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15. Experimental and Numerical Investigation of Transonic Bump Flow

Author

Huang, J. -C., Barakos, G., Benard, E., Barbut, G., Hoarau, Y., Braza, M., Derian, P., Hirschel, Ernst Heinrich, editor, Schröder, Wolfgang, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Shokin, Yurii I., editor, Peng, Shia-Hui, editor, and Doerffer, Piotr, editor

Published
2010
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16. Prediction of Transonic Buffet around a Wing with Flap

Author

Barbut, G., Braza, M., Hoarau, Y., Barakos, G., Sévrain, A., Vos, J. B., Hirschel, Ernst Heinrich, editor, Schröder, Wolfgang, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Shokin, Yurii I., editor, Peng, Shia-Hui, editor, and Doerffer, Piotr, editor

Published
2010
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17. DES for UCAV Weapon Bay Flow

Author

Lawson, S. J., Barakos, G. N., Hirschel, Ernst Heinrich, editor, Schröder, Wolfgang, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Shokin, Yurii I., editor, Peng, Shia-Hui, editor, and Doerffer, Piotr, editor

Published
2010
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21. Summary of work carried out in the main tasks of the UNSI project

Author

Braza, M., Berton, E., Allain, C., Favier, D., Maresca, C., Selmin, Vittorio, Evans, J., Schwarmborn, D., Weinman, K. A., Teupootahiti, E., Dervieux, A., Koobus, B., de C Henshaw, Michael J., Smith, Jonathan, Abbas, A., Guerra, J., Haase, W., Schweiger, J., Berggren, M., Alpesh, A., Karlsson, A., Winzell, B., Barakos, G., Drikakis, D., Girodroux-Lavigne, P., Bunge, U., Palacios, R., Climent, H., Hirschel, Ernst Heinrich, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Selmin, Vittorio, editor, and Winzell, Bengt, editor

Published
2003
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22. Application-oriented synthesis of work

Author

Barakos, G., Drikakis, D., Mary, Queen, Wang, D., Wallin, S., Eliasson, P., Berggren, M., Bouhadji, A., Bourdet, S., Braza, M., Hoarau, Y., Rodes, P., Ruiz, D., Selmin, Vittorio, Evans, J., Schwarmborn, D., Weinman, K., Girodroux-Lavigne, P., Mortchelewicz, G. D., de C Henshaw, Michael J., Smith, Jonathan, Girodroux-Lavigne, Philippe, Grisval, Jean-Pierre, Guillemot, Stephane, Teupootahiti, Edwin, Aviation, Dassault, Karlsson, Anders, Winzell, Bengt, Grashof, J., Haase, W., Schneider, M., Schweiger, J., Stettner, M., Bunge, Ulf, Thiele, Frank, Hirschel, Ernst Heinrich, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Selmin, Vittorio, editor, and Winzell, Bengt, editor

Published
2003
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23. Technical, partner reports containing method descriptions and concise presentation of important results

Author

Selmin, V., de C Henshaw, Michael J., Smith, Jonathan, Guerra, J. J., Abbas, A., Grashof, J., Haase, W., Schneider, M., Schweiger, J., Stettner, M., Guillemot, Stéphane, Roques, Olivier, Teupootahiti, Edwin, Aviation, Dassault, Catherall, D., Evans, J., Schwarmborn, D., Weinman, K., Berggren, M., Wallin, S., Wang, D., Johansson, C., Eliasson, P., Bouhadji, A., Bourdet, S., Braza, M., Hoarau, Y., Rodes, P., Tzabiras, G., Berton, E., Allain, C., Favier, D., Maresca, C., Patel, Alpesh, Hirsch, Charles, Girodroux-Lavigne, P., Grisval, J. P., Le Balleur, J. C., Mortchelewicz, G. D., Barakos, G., Drikakis, D., Winzell, B., Karlsson, A., Bunge, Ulf, Rung, Thomas, Thiele, Frank, Hirschel, Ernst Heinrich, editor, Fujii, Kozo, editor, Haase, Werner, editor, van Leer, Bram, editor, Leschziner, Michael A., editor, Pandolfi, Maurizio, editor, Periaux, Jacques, editor, Rizzi, Arthur, editor, Roux, Bernard, editor, Selmin, Vittorio, editor, and Winzell, Bengt, editor

Published
2003
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27. Main rotor-body action for virtual blades model

Author

Kusyumov Alexander, Kusyumov Sergey, Mikhailov Sergey, Romanova Elena, Phayzullin Konstantin, Lopatin Evgeny, and Barakos G.

Subjects
Physics, QC1-999
Abstract

This research aims to investigate a virtual blade model and assess rotor influence on helicopter fuselage aerodynamics. The rotor disk is discretized in the azimuthal direction, and a time-varied pressure jump is applied in regions occupied by the blades. To obtain the pressure jump, an actuator disk is employed using uniform and non-uniform blade load distribution, based on momentum theory.

Published
2018
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31. Modal Characterisation of Rotor/Propeller Rig for Tip-Mach Scaled Wind Tunnel Testing

Author

Tatar, A., Wu, J., Zagaglia, D., Titurus, B., Rezgui, D., Green, R. B., and Barakos, G.

Abstract

An advanced rotor and propeller rig for tip Mach-scaled wind tunnel testing is the subject of dynamic analysis\ud presented in this paper. Experimental modal analysis and finite element method are used to assess the key\ud characteristics such as the modal properties and transfer functions, as well as their changes under varying\ud conditions. This work aims to determine and summarize these characteristics for the purposes of further rig\ud development and its safe operation. The research also includes analysis of the key sources of uncertainty,\ud damping, the effect of unbalanced excitation and model-experiment correlation. The low frequency region is\ud found to be dominated by the three weakly damped global modes whilst the following modes feature increased\ud modal activity of the rotor shaft and the hub. The latter set of modes is also found to be more susceptible to\ud nonlinear effects and associated increased identification and modelling uncertainty.

Published
2021

38. Distribution of Acoustic Power Spectra for an Isolated Helicopter Fuselage

Author

Kusyumov A.N., Mikhailov S.A., Garipova L.I., Batrakov A.S., and Barakos G.

Subjects
Physics, QC1-999
Abstract

The broadband aerodynamic noise can be studied, assuming isotropic flow, turbulence and decay. Proudman’s approach allows practical calculations of noise based on CFD solutions of RANS or URANS equations at the stage of post processing and analysis of the solution. Another aspect is the broadband acoustic spectrum and the distribution of acoustic power over a range of frequencies. The acoustic energy spectrum distribution in isotropic turbulence is non monotonic and has a maximum at a certain value of Strouhal number. In the present work the value of acoustic power peak frequency is determined using a prescribed form of acoustic energy spectrum distribution presented in papers by S. Sarkar and M. Y. Hussaini and by G. M. Lilley. CFD modelling of the flow around isolated helicopter fuselage model was considered using the HMB CFD code and the RANS equations.

Published
2016
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39. Flight simulation testing of a turbulence model based on a Synthetic Eddy Method

Author

Huecas, SH, White, M, and Barakos, G

Subjects
Physics::Fluid Dynamics, Physics::Space Physics, Physics::Atmospheric and Oceanic Physics
Abstract

This paper presents initial analysis of an ongoing series of flight simulation trials of a new turbulence model based on a synthetic eddy method (SEM). The model is based on the generation of a random distribution of turbulence generating Eddies within a control model surrounding the aircraft. Eddies are displaced by the flow and regenerated at the inflow as they leave the simulation domain. The model allows adjustment of turbulence intensity by adjusting the value of Reynolds stress tensor and of frequency spectra through adjustment of eddy sizes, allowing for a more realistic representation of broadband turbulence. Compared to other random turbulence models, preserving the location of the Eddies in the control volume ensures automatically that turbulence across different aircraft locations is automatically correlated. Piloted flight simulation tests show that both, levels of turbulence intensity and frequency of the induced turbulence have a strong effect on workload and task performance. Increases in turbulence intensity result in a direct increase in pilot workload and reduced task performance. However changes in frequency of turbulence present a more complex picture dependent on flight condition and aircraft response.

Published
2020

41. Investigation of three-dimensional dynamic stall using computational fluid dynamics

Author

Spentzos, A., Barakos, G., Badcock, K., Richards, B., Wernert, P., Schreck, S., and Raffel, M.

Subjects
Aerodynamics, Supersonic -- Testing, Fluid dynamics -- Testing, Airplanes -- Wings, Airplanes -- Mechanical properties, Airplanes -- Testing, Aerospace and defense industries, Business
Abstract

Numerical simulation of three-dimensional dynamic stall has been undertaken using computational fluid dynamics. The full Navier-Stokes equations, coupled with a two-equation turbulence model, where appropriate, have been solved on multiblock strucured grids in a time-accurate fashion. Results have been obtained for wings of square planform and of NACA 0012 section. Efforts have been devoted to the accurate modeling of the flow near the wing tips, which, for this case, were sharp without tip caps. The obtained results revealed the time evolution of the dynamic stall vortex, which, for this case, takes the shape of a capital omega [OMEGA] spanning the wing. The obtained results compare well against experimental data both for the surface pressure distribution on the wing and the flow topology. Of significant importance is the interaction between the three-dimensional dynamic stall vortex and the tip vortex. The present results indicate that once the two vortices are formed both appear to originate from the same region, which is located near the leading edge of the tip. The overall configuration of the developed vortical system takes a II-[OMEGA] form. To our knowledge, this is the first detailed numerical study of three-dimensional dynamic stall appearing in the literature.

Published
2005

45. Prediction of helicopter rotor noise in hover

Author

Kusyumov A.N., Mikhailov S.A., Garipova L.I., Batrakov A.S., and Barakos G.

Subjects
Physics, QC1-999
Abstract

Two mathematical models are used in this work to estimate the acoustics of a hovering main rotor. The first model is based on the Ffowcs Williams-Howkings equations using the formulation of Farassat. An analytical approach is followed for this model, to determine the thickness and load noise contributions of the rotor blade in hover. The second approach allows using URANS and RANS CFD solutions and based on numerical solution of the Ffowcs Williams-Howkings equations. The employed test cases correspond to a model rotor available at the KNRTUKAI aerodynamics laboratory. The laboratory is equipped with a system of acoustic measurements, and comparisons between predictions and measurements are to be attempted as part of this work.

Published
2015
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49. Improvement to numerical predictions of aerodynamic flows using experimental data assimilation

Author

Barakos, G., Drikakis, D., and Lefebre, W.

Subjects
Turbulence -- Research, Aerofoils -- Research, Aerospace and defense industries, Business, Science and technology
Abstract

The use of experimental data assimilation in aerodynamic computations of turbulent compressible flows over airfoils was investigated. The data assimilation approach is implemented together with a compressible and turbulent Navier-Stokes solver, and the effects of pressure and velocity forcing on numerical predictions of flows, were studied. Pressure forcing for the subsonic flow was marginal although it improved the numerical prediction of transonic flow. Velocity forcing had positive effects on subsonic and transonic flow simulations.

Published
1999

50. A Simulation-Based Study on Reprocessing of Phosphate Tailings for Recovering Pyrochlore and Monazite

Author

Vicino Pacheco De Aquino, T., Pereira, L., Hassanzadehmahaleh, A., Belo Fernandes, I., Rudolph, M., Mischo, H., and Barakos, G.

Subjects
HSC Sim®, rare earth elements (REE), phosphate deposit, Pyrochlore, process simulation
Abstract

The present study aims to investigate possibilities for improving the recovery of pyrochlore ((Na, Ca)₂Nb₂O₆) and monazite ((Ce, La, Th, Sm)PO4) as by-products from a phosphate mine with current niobium (Nb) production from geometallurgical perspectives. With this purpose, process mineralogy of Nb- and REE-bearing minerals together with operating properties of the concentration plant are examined using respectively mineral liberation analyzer (MLA) and the HSC® Chemistry 9 simulation module. A plant-site sampling campaign was performed and key operating parameters such as throughputs and pulp densities for individual streams were measured. The results obtained by MLA analyses as the base of mineral mass balances were compared and validated by commonly used chemical characterization techniques i.e. X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma–optical emission spectroscopy (ICP-OES). Simulation results showed that the combination of Nb flotation rougher and scavenger cells into one single rougher bank plus the addition of a new scavenger bank (4x1.4 m³ cells) can increase pyrochlore recovery in the silica/niobium flotation circuit from approximately 31% to 44%. This cell configuration improves the ultimate pyrochlore’s plant recovery from 27% to 38% leading to a substantial enhancement in final concentrate throughput from 540 to 740 kg/h. Future studies on this topic include the use of wet high intensity magnetic separation (WHIMS) and froth flotation respectively for the pre-concentration and concentration of monazite.

Published
2019

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