Добірка наукової літератури з теми "Tourbillon de sillage"
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Статті в журналах з теми "Tourbillon de sillage":
Dolfi-Bouteyre, Agnès, Laurent Lombard, Alexandre Hallermeyer, Matthieu Valla, and Claudine Besson. "Détection et caractérisation des tourbillons de sillage des avions par Lidar Doppler." Photoniques, no. 97 (July 2019): 36–39. http://dx.doi.org/10.1051/photon/20199736.
Dolfi-Bouteyre, Agnès, Laurent Lombard, Alexandre Hallermeyer, Matthieu Valla, and Claudine Besson. "Détection et caractérisation des tourbillons de sillage des avions par Lidar Doppler." Photoniques, no. 84 (November 2016): 28–30. http://dx.doi.org/10.1051/photon/20168428.
Дисертації з теми "Tourbillon de sillage":
Sablon, Julien. "Dynamique des tourbillons de sillage stratifiés radialement." Electronic Thesis or Diss., Toulouse, ISAE, 2023. http://www.theses.fr/2023ESAE0070.
The aim of this PhD thesis is to study the stability of a flow representative of trailing vortices generated by aircraft. To this end, two methods of increasing complexity have been used to analyse the stability of the q-vortex model, an approximation of the Batchelor (1964) vortex with the addition of a variable density profile. The first one, the modal linear stability analysis, allows to find the most amplified modes by solving an eigenvalue problem. Given the stationarity and double spatial homogeneity of the base flow field, this method is computationally efficient, allowing a thorough exploration of the problem's parameter space. The second method, the non-modal linear stability analysis, deals with the potential for transient growth mechanisms using a direct-adjoint approach. The use of this methodology is justified by the non-normal character of the Navier–Stokes operator.In the first part, the three-dimensional modal linear stability analysis of the q-vortex is studied. This analysis shows that the vortex stability is substantially modified by the presence of a variable-density profile. When the vortex core is heavier than the external environment, the instability domain, limited to low swirl numbers (q <1.5) in the constant density case, is extended to high swirl numbers. The associated instabilities exhibit high amplification rates and are associated to the Rayleigh–Taylor instability (RTI) mechanism, already identified at infinite swirl numbers for the Lamb–Oseen vortex (Joly et al., 2005). Conversely, the presence of a light core stabilises the flow for large swirl numbers. The effect of the vorticity-to-density radius ratio Ɛ depends on the other parameters. At high Reynolds and swirl numbers, the amplification rate increases continuously with Ɛ. On the other hand, at low swirl numbers (for any Reynolds value) or at high swirl numbers only at low Reynolds, the response to the concentration of the density profile at the centre of the vortex is not monotonic, and there is an optimum value for this ratio close to Ɛ ≈ 2.The second part of the thesis is devoted to the non-modal linear stability analysis of the flow. As this type of analysis had not yet been carried out on a vortex flow with a radial variation of density, the code validation step involved the development of a modal code for determining the adjoint perturbations. These adjoint modes correspond to the optimal excitation leading to maximum energy gain at long times, they are presented briefly. The sensitivity of the optimisation problem to the choice of the energy norm, the initial conditions and the base flow field is studied. Considering the latter, an unsteady modelling of the base flow is conducted via nonlinear simulations initialised from the variable-density q-vortex. At very high Reynolds numbers, viscous diffusion is negligible and the flow can be considered stationary and correctly approximated by the initial analytical solution. However, this is no longer the case at moderate Reynolds numbers, where the base flow becomes unsteady. Approximation via the steady analytical q-vortex-like solution is therefore less suitable for this regime. Finally, the variation of the optimal perturbation at different flow parameters is analysed. In particular, the Orr mechanism for transient energy growth is identified as the main mechanism responsible for the increase in perturbation growth rate at short times
Coppens, Fabien. "Simulations numériques sur le développement de la turbulence dans un tourbillon." Toulouse, INPT, 1998. http://www.theses.fr/1998INPT014H.
Joly, Cécile. "Simulations numériques d'un jet rond turbulent et de son interaction avec un tourbillon de sillage." Université de Marne-la-Vallée, 2002. http://www.theses.fr/2002MARN0147.
The general context of this study concerns the impact of contrails, these famous white plumes frequently observed in the aircraft wake, on the atmosphere. From an aerodynamic point of view, the formation of the contrails is characterised by the interaction between a turbulent jet and a wing-tip vortex. The aim of this thesis is to contribute to a better understanding of the thermal and dynamic phenomena involved in this flow. This work is based on the numerical resolution of the three-dimensional, unsteady and compressible Navier-Stokes and energy conservation equations. Two approaches are considered: the direct numerical simulation and the large eddy simulation. A temporal simulation of the transition to turbulence of a non-isothermal jet is performed without accounting for the vortex flow field. A the end of this simulation, a vortex model is superimposed on the jet flow field. The first part of this thesis describes the two approaches, the different subgrid models chosen for the large eddy simulations, and the numerical techniques employed. The second part is devoted to the jet flow simulation, and here the objective is to determine the subgrid model appropriated to this flow configuration. The third part is dedicated to the simulation of interaction between the jet and the vortex. Results are compared to experimental data. The simulations have demonstrated the development of large scale structures all around the vortex core. The temperature field concentrates in the large scale structures
Nybelen, Laurent. "Etude numérique d'écoulements tourbillonnaires de sillage d'avion." Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00450477.
Thomas, Olivier. "Simulations numériques de perturbations d’un tourbillon de Lamb-Oseen : application à l’éclatement tourbillonnaire dans les sillages des avions de transport." Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00814536.
This report synthesizes the works performed on the theme of end effects and vortex bursting observed in experimental facilities such as catapult wind tunnels or towing tanks, whose aim it is to characterize the wake vortices of civil aircraft. It includes a bibliographical synthesis, the post-processing of experimental campaigns performed in the B20 wind tunnel in ONERA Lille, the presentation of the Direct Numerical Simulation FLUDILES code, the modelling of the disturbances of a Lamb-Oseen vortex and the confirmation of DNS calculations upon the linear stability theory, the numerical and theoretical study of the nonlinear dynamics of a Lamb-Oseen vortex by means of DNS
Thomas, Olivier. "Simulations numériques de perturbations d'un tourbillon de Lamb-Oseen : application à l'éclatement tourbillonnaire dans les sillages des avions de transport." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00814536.
Bolnot, Hadrien. "Instabilités des tourbillons hélicoïdaux : application au sillage des rotors." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4825/document.
This thesis is devoted to the stability properties of helical vortices, which are of interest for applications such as helicopter and wind turbine wakes.In a first part, the spatio-temporal development of the pairing instability is characterised for an infinite array of vortex rings, using a pseudo-spectral numerical code. We show that this axisymmetric flow model is indeed a good approximation of the helical system in the limit of large helix radius and small pitch. Under these assumptions, and by using appropriate dimensionless variables, we also show that the theoretical result concerning the spatio-temporal growth rate for a double row of point vortices represents a good prediction for the helical case.In a second part, we describe how one or several helical vortices were generated in a carefully controlled way using small-scale rotor models in the water channel of the laboratory. Introducing perturbations with well-defined amplitudes and frequencies, the growth rate of the pairing instability could be measured experimentally and compared to theoretical predictions. The non-linear evolution of these perturbations, as well as other unstable modes of smaller wavelengths, were also observed experimentally for the first time.Finally, these results were applied to helicopter wakes for the prediction of the Vortex Ring State (VRS) regime and to the transition to turbulence in wind turbine wakes
Riera, William. "Evaluation of the ZDES method on an axial compressor : analysis of the effects of upstream wake and throttle on the tip-leakage flow." Thesis, Ecully, Ecole centrale de Lyon, 2014. http://www.theses.fr/2014ECDL0030/document.
The tip-leakage flow in axial compressors is studied with the Zonal Detached Eddy Simulation (ZDES). This study aims at evaluating the capability of hybrid URANS/LES methods to simulate the tip-leakage flow within a realistic axial compressor in order to better understand the involved physics, especially the behaviour of the flow near surge and the effects of stator wakes on the downstream rotor. Once the ZDES method is chosen, a numerical test bench is defined to simulate the first rotor of the research compressor CREATE. This bench takes into account the unsteady effects of the Inlet Guide Vane (IGV), such as its wake as well as vortices generated at the IGV hub and tip. It is based upon ZDES meshing criteria and is used to evaluate this method compared to classic RANS and URANS approaches. A method validation is carried out up to a spectral analysis compared to experimental data. The ZDES is capable to capture more accurately the intensity and position of the unsteady phenomena encountered in the tip region, especially the tip-leakage vortex. The power spectral densities highlight that this partly originates from a better capture of the energy transfer from large to small structures until their dissipation. The discrepancy between the methods is accentuated as the tip-leakage vortex crosses the shock. Near the surge line, the interactions between the shock, the tip-leakage vortex, the boundary layer developing on the shroud and the vortex generated by the IGV tip are amplified. The boundary layer on the shroud separates earlier and a local flow inversion occurs. Besides, the tip-leakage vortex widens and is deflected toward the adjacent blade. This strengthens the double leakage. At the design operating point, the interaction of the IGV tip vortex with the shock and the rotor tip vortex is studied. A vortex flutter is observed as the IGV tip vortex arrives on the rotor blade and stretches the rotor tip vortex. This phenomenon decreases the double leakage
Moet, Henri. "Simulation numérique du comportement des tourbillons de sillage dans l'atmosphère." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT007H.
Meunier, Patrice. "Tourbilons et sillages dans les fluides géophysiques." Habilitation à diriger des recherches, Université de Provence - Aix-Marseille I, 2009. http://tel.archives-ouvertes.fr/tel-00426779.