Notre thèse vise à étudier les conséquences d’une ablation totale ou partielle de la glande thyroïde suite à un dysfonctionnement thyroïdien, suivie ou non d’un traitement radiothérapique, et ce dans le domaine de la phonétique clinique. Ce type d’intervention perturbe généralement le système de production de la parole et conduit parfois à une dégradation de la qualité vocale de façon permanente (moins de 5% des cas) ou passagère. Le travail se veut une contribution aux recherches menées en linguistique et phonétique cliniques, plus particulièrement dans le cadre de l’analyse de faits compensatoires ou de réajustements mis en place par des patients, suite à une perturbation provoquée au niveau du fonctionnement de leur système phonatoire. Le travail a été effectué en collaboration avec le Groupe Hospitalier Saint-Vincent, et plus particulièrement avec la Clinique Sainte-Anne de Strasbourg, où se trouve le département de chirurgie thyroïdienne. Notre étude est longitudinale puisque nous avons suivi une cohorte de patients opérés de la glande thyroïde durant une année au moins, à raison d’une acquisition de données acoustiques et aérodynamiques par mois, l’examen post-opératoire ayant révélé ou non une lésion de la mobilité des plis vocaux. Nous avons étudié les possibles stratégies de compensation ou de réajustement que les patients ont pu mettre en place seuls ou à l’aide d’une rééducation orthophonique, et ce afin d’évaluer la flexibilité du système de production de la parole. Il s’agit donc d’étudier la flexibilité du système de production et de perception de la parole et de tenter de comprendre ce système à partir d’un dysfonctionnement d’origine pathologique. Il est ainsi question de déterminer les limites des déviations physiques imposées par les exigences linguistiques de clarté du système de perception de la parole. Par les différentes investigations que nous avons menées, nous avons tâché de rendre compte de la viabilité possible des unités phonétiques et phonologiques perceptivement stables, malgré une variabilité omniprésente dans le substrat physique, articulatoire, physiologique et acoustique. Une attention particulière est accordée aux dimensions sociétales liées à la qualité de vie (fatigue vocale, satisfaction des productions linguistiques, considération de soi, etc.). / Our thesis aims at studying the consequences of total or partial removal of the thyroid gland due to thyroid dysfunction, followed or not by a radiotherapy treatment, in the field of clinical phonetics. This type of intervention usually perturbs the speech production system and sometimes leads to permanent (less than 5% of cases) or transient degradation of voice quality. The work intends to be a contribution to research carried out in clinical linguistics and phonetics, more particularly in the area of compensatory or readjustment phenomena developed by patients, following perturbation provoked in their phonatory system. The work was carried out in collaboration with the Group Saint-Vincent Hospital, and more particularly with the Clinique Sainte-Anne of Strasbourg, within the department of thyroid surgery. Our study is longitudinal since we have followed a cohort of patients, who underwent thyroid gland surgery, for at least one year, acquiring acoustic and aerodynamic data every month, the postoperative examination having revealed or not a lesion in the mobility of the vocal folds. We have studied possible compensation or readjustment strategies that patients were able to deploy by themselves or with the help of speech therapy, in order to assess the flexibility of the speech production system. The purpose is thus to evaluate the flexibility of the speech production and perception system and to try to understand how this system works based on a specific dysfunction of pathological origin. It is thus a question of determining the limits of physical deviations imposed by linguistic requirements of clarity of the speech perception system. Through the various investigations that we have conducted, we have tried to account for possible viability of perceptually stable phonetic and phonological units, despite an omnipresent variability in the physical, articulatory, physiological and acoustic substrate. Particular attention is paid to societal dimensions related to quality of life (vocal fatigue, satisfaction of linguistic productions, self-esteem, etc.).

Ce travail de thèse s'inscrit dans la thématique de la pollution particulaire de l'air intérieur et concerne plus particulièrement les phénomènes de remise en suspension liés à l'impact, au niveau du sol, des pas d'une personne qui marche sur un plancher chargé en particules. La première partie présente un état de l'art des connaissances de la pollution particulaire. Les différents paramètres expérimentaux qui influencent la remise en suspension des particules ainsi que les coefficients utilisés pour la quantification du phénomène sont recensés. Les différentes perturbations mécaniques et aérodynamiques générées lors de l'impact d'un pied avec le sol pendant la marche d'une personne sont présentées et comparées. Nous terminons la première partie par une présentation des différents modèles de remise en suspension des particules émanant d'une surface. La seconde partie est consacrée à la présentation de la maquette qui a été mise au point au laboratoire LaSIE à La Rochelle afin d'étudier le dépôt et la remise en suspension des particules par un simulateur mécanique du pas humain depuis un sol chargé en particules. Cette étude a permis de classer les différents types de surfaces utilisées dans le bâtiment en fonction de leurs émissions en particules après l'impact mécanique d'un solide. La troisième partie du travail consiste à mesurer les vitesses de l'écoulement de l'air généré par un simulateur mécanique automatisé du pas humain en différents emplacements. Les mesures de la vitesse ont été effectuées par trois types de méthodes largement utilisées dans le domaine de la mécanique des fluides : deux méthodes de Vélocimétrie Laser (Vélocimétrie par Image des particules et Vélocimétrie Laser Doppler), mais également une méthode d’Anémométrie à Fil Chaud. Ces mesures nous ont permis de trouver la zone de forte vitesse qui correspond à la zone où nous avons une remise en suspension importante. Nous avons également étudié l'influence de l'état de la surface sur les vitesses de l'écoulement générées à proximité du sol suite au mouvement du simulateur mécanique. Ces mesures ont mis en évidence que l'influence de la rugosité de la surface sur la vitesse de l'écoulement généré par le pas est marginale. Finalement, nous avons étudié analytiquement le détachement des particules en utilisant un modèle basé sur le bilan des moments de forces. Des perspectives à la fois sur l'amélioration des deux maquettes mises en place au LaSIE et à l'ERM, ainsi que le développement d'un code numérique pour simuler le pas humain sont présentées et argumentées en conclusion. / This thesis work is part of indoor air particle pollution theme and more particularly the phenomenon of walking-induced particle resuspension. The first part presents a state of the art knowledge of particulate pollution. The different experimental parameters that influence the particles resuspension, as well as the coefficients used for the phenomenon quantification, are identified. The various mechanical and aerodynamic disturbances generated during person walking are presented and compared. We end the first part with a presentation of the different particles resuspension models. The second part is dedicated to present the experiment made on a small scale model developed at the LaSIE laboratory in La Rochelle to study particles deposition and resuspension by amechanical simulator of the human step from a particle-laden soil. This study classified the different types of surfaces used in the building according to their particulate emissions after the mechanical simulator impact. The third part of the work consists of measuring the airflow velocities generated by an automated mechanical simulator of the human footstep at different locations. The velocity measurements have been done in the Royal Military Academy at Brussels (RMA) by three types of methods widely used in the field of fluid mechanics : two methods of Laser Velocimetry (Particle Image Velocimetry and Laser Doppler Velocimetry), but also a method of Wire Anemometry. These measurements allowed us to find the high-speed zone that corresponds to the area where we have a significant resuspension. We also studied the influence the surface roughness on the flow velocities generated near the ground following the movement of the mechanical simulator. We have shown that the influence of the surface roughness on the speed of the flow generated by the pitch is marginal. Finally, we analytically studied the detachment of particles using a model based on the momentum balance. Perspectives on both the improvement of the two models set up in LaSIE and the RMA, as well as the development of a numerical code to simulate the human step, are presented and argued in conclusion.

Au cours du siècle dernier, la communauté scientifique a traité le contrôle des véhicules aériens principalement par l'élaboration de stratégies ad hoc, mais aucune approche unifiée n'a été développé jusqu'à présent. Cette thèse participe à l'élaboration d'une approche unifiée pour le contrôle des véhicules aériens en prenant en compte les forces aérodynamiques dans la conception de la commande. Nous supposons les effets aérodynamiques de rotation et les effets non stationnaires négligeables. Les actionneurs du véhicule sont supposés être composés d'une force de poussé fixée au corps pour le mouvement en translation, et d'un couple de contrôle pour la régulation d'attitude. Cette thèse se concentre ensuite sur la boucle de guidage, traitant du contrôle de la vitesse linéaire. L'un des principaux objectifs a été de déterminer la façon de réguler la force de poussée et l'orientation du véhicule pour compenser les forces extérieures. Tout d'abord nous abordons la modélisation, l'analyse et le contrôle de la dynamique longitudinale de l'avion. Ensuite nous étendons certaines de ces études aux mouvements tridimensionnels d'avions au corps symétrique, tels que les missiles. Un résultat original de cette thèse est de préciser les conditions sur la force aérodynamique permettant de reformuler le problème du contrôle dans celui de la commande d'un corps sphérique, pour lequel des résultats de stabilité peuvent être démontrés. Les lois de commande proposées intègrent des termes intégraux et anti-wind up sans reposer sur une politique de commutation entre plusieurs lois de commande. / Over the last century, the scientific community has dealt with the control of flying machines by mainly developing different strategies in relation to different classes of aircraft, and no unified control approach has been developed so far. The present thesis contributes towards the development of a unified control approach for aerial vehicles by maintaining aerodynamic forces in the control design. It is assumed, however, that the aerodynamic effects of rotational and unsteady motions are negligible, and that the means of actuation for an aerial vehicle consist of a body-fixed thrust force for translational motion and a control torque for attitude monitoring. This thesis then focuses on the guidance loop of the control problem. One of the main objectives has been to determine how to regulate the thrust intensity and the vehicle orientation to compensate for the orientation-dependent external forces. In particular, the modeling, analysis, and control of the longitudinal aircraft dynamics is first addressed. Then, some of these studies are extended to three-dimensional motions of symmetric aircraft, such as missile-like bodies. An original outcome of this thesis is to state conditions on the aerodynamic force that allow the control problem to be recasted into that of controlling a spherical body. In this case, strong stability results can be shown. The proposed control laws incorporate integral and anti-wind up terms and do not rely on a switching policy between several control laws.

L’objectif de ce travail de thèse consiste à analyser les solutions de contrôle permettant de réduire la traînée aérodynamique et donc de diminuer la consommation d’un véhicule. Les véhicules ciblés dans cette étude sont ceux se rapprochant d’une géométrie à culot droit telles que les versions break, monospace, SUV, utilitaires, ou même les remorques de camions. Pour s’affranchir des variantes de style, ces travaux sont concentrés sur la géométrie académique du corps de Ahmed à culot droit. La vitesse de l’écoulement est de 30m/s afin de retrouver des caractéristiques d’un écoulement de sillage fortement turbulent, proche des vitesses d’un véhicule sur autoroute. Ce travail à dominante numérique se décompose en deux parties : la première a pour objectif de valider les résultats de calculs avec et sans solution de contrôle avec des mesures expérimentales identiques, la seconde d’explorer numériquement des configurations de contrôle mixant des solutions de jets périodiques et de déflecteurs agissant sur le sillage du corps de Ahmed à culot droit. Les solutions les plus efficaces apportent des réductions de la traînée de l’ordre de 10%. / This present work is focused on the analysis of control solutions that reduce the aerodynamic drag and therefore the fuel consumption of vehicles. The selected vehicle geometries are closed to a bluff body such as Estate, van, SUV, commercial vehicles or even truck trailers. This work is then focused on the academic geometry of Ahmed body with square back in order to avoid style diversity. The reference velocity flow is equal to 30m/s, which is closed to a vehicle speed on a highway, and induces a highly turbulent wake flow. This work mainly numerical is divided in two parts. The first one is dedicated to the validation of the numerical model with experimental wind tunnel measurements. The second part looks for numerical configurations of flow control solution, mixing periodic jet and deflector both acting on the wake. Most effective solutions lead to drag reduction of about 10%.

Afin de faire face aux fortes températures rencontrées par les composantsen aval de la chambre de combustion, des prélèvements d’air plus frais sont réalisésau niveau du compresseur. Cet air alimente les cavités en pied de turbine et refroidiles disques rotor permettant d’assurer le bon fonctionnement de la turbine.Ce manuscrit présente une étude numérique de l’effet de ces écoulements de cavitéau pied de la turbine sur ses performances aérodynamiques. Les phénomènesd’interaction entre l’air de cavité en pied de turbine et l’air de veine principal est unphénomène encore difficilement compris. L’étude de ces phénomènes est réalisée autravers de différentes approches numériques (RANS, LES et LES-LBM) appliquéesà deux configurations pour lesquelles des résultats expérimentaux s ont disponibles.Une première configuration en grille d’aube linéaire en amont de laquelle différentesgéométries d’entrefer (interface entre plateforme rotor et stator) et débits de cavitépouvaient être variés. Une seconde configuration annulaire composée de deux étagesde turbine comprenant les cavités en pied et plus proche d’une configuration industrielle.Les pertes additionnelles associées à l’écoulement de cavité sont mesurées etétudiées à l’aide d’une méthode basée sur l’exergie (bilans d’énergie dans l’objectifde générer du travail). / In order to deal with high temperatures faced by the components downstreamof the combustion chamber, some relatively cold air is bled at the compressor.This air feeds the cavities under the turbine main annulus and cool down the rotordisks ensuring a proper and safe operation of the turbine. This thesis manuscriptintroduces a numerical study of the effect of the cavity flow close to the turbine hubon its aerodynamic performance. The interaction phenomena between the cav-ity andmain annulus flow are not currently fully understood. The study of these phenomenais performed based on different numerical approaches (RANS, LES and LES-LBM)applied to two configurations for which experimental results are avail-able. A linearcascade configuration with an upstream cavity and various rim seal geometries(interface between rotor and stator platform) and cavity flow rate avail-able. Arotating configuration that is a two stage turbine including cavities close to realisticindustrial configurations. Additional losses incurred by the cavity flow are measuredand studied using a method based on exergy (energy balance in the purpose togenerate work).

There is currently a great deal of interest within the aviation community in the design of small, slow-flying but manoeuvrable uninhabited vehicles for reconnaissance, surveillance, and search and rescue operations in urban environments. Inspired by observation of birds, insects, fish and cetaceans, flapping wings are being actively studied in the hope that they may provide greater propulsive efficiencies than propellers and rotors at low Reynolds numbers for such Micro-Air Vehicles (MAVs). Researchers have posited the Strouhal number (combining flapping frequency, amplitude and forward speed) as the parameter controlling flapping wing aerodynamics in cruising flight, although there is conflicting evidence. This thesis explores the effect of flapping frequency and amplitude on forces and wake structures, as well as physical mechanisms leading to optimum propulsive efficiency. Two-dimensional rigid airfoils are considered at Reynolds number 2,000 ??? 40,000. A compressible Navier-Stokes simulation is combined with numerical and analytical potential flow techniques to isolate and evaluate the effect of viscosity, leading and trailing edge vortex separation, and wake vortex dynamics. The wake structures of a plunging airfoil are shown to be sensitive to the flapping frequency independent of the Strouhal number. For a given frequency, the wake of the airfoil exhibits ???vortex lock-in??? as the amplitude of motion is increased, in a manner analogous to an oscillating circular cylinder. This is caused by interaction between the flapping frequency and the ???bluff-body??? vortex shedding frequency apparent even for streamlined airfoils at low Reynolds number. The thrust and propulsive efficiency of a plunging airfoil are also shown to be sensitive to the flapping frequency independent of Strouhal number. This dependence is the result of vortex shedding from the leading edge, and an interaction between the flapping frequency and the time for vortex formation, separation and convection over the airfoil surface. The observed propulsive efficiency peak for a pitching and plunging airfoil is shown to be the result of leading edge vortex shedding at low flapping frequencies (low Strouhal numbers), and high power requirements at large flapping amplitudes (high Strouhal numbers). The efficiency peak is governed by flapping frequency and amplitude separately, rather than the Strouhal number directly.

The context of this thesis is the numerical simulation of turbulent flows at moderate Reynolds numbers and the improvement of the capabilities of an in-house 3D unsteady and incompressible flow solver called SFELES to simulate such flows. In addition to this abstract, this thesis includes five other chapters. The second chapter of this thesis presents the numerical methods implemented in the two CFD solvers used as part of this work, namely SFELES and PHASTA. The third chapter concentrates on the implementation of a new library called FlexMG. This library allows the use of various types of iterative solvers preconditioned by algebraic multigrid methods, which require much less memory to solve linear systems than a direct sparse LU solver available in SFELES. Multigrid is an iterative procedure that relies on a series of increasingly coarser approximations of the original 'fine' problem. The underlying concept is the following: low wavenumber errors on fine grids become high wavenumber errors on coarser levels, which can be effectively removed by applying fixed-point methods on coarser levels. Two families of algebraic multigrid preconditioners have been implemented in FlexMG, namely smooth aggregation-type and non-nested finite element-type. Unlike pure gridless multigrid, both of these families use the information contained in the initial fine mesh. A hierarchy of coarse meshes is also needed for the non-nested finite element-type multigrid so that our approaches can be considered as hybrid. Our aggregation-type multigrid is smoothed with either a constant or a linear least square fitting function, whereas the non-nested finite element-type multigrid is already smooth by construction. All these multigrid preconditioners are tested as stand-alone solvers or coupled with a GMRES (Generalized Minimal RESidual) method. After analyzing the accuracy of the solutions obtained with our solvers on a typical test case in fluid mechanics (unsteady flow past a circular cylinder at low Reynolds number), their performance in terms of convergence rate, computational speed and memory consumption is compared with the performance of a direct sparse LU solver as a reference. Finally, the importance of using smooth interpolation operators is also underlined in this work. The fourth chapter is devoted to the study of subgrid scale models for the large eddy simulation (LES) of turbulent flows. It is well known that turbulence features a cascade process by which kinetic energy is transferred from the large turbulent scales to the smaller ones. Below a certain size, the smallest structures are dissipated into heat because of the effect of the viscous term in the Navier-Stokes equations. In the classical formulation of LES models, all the resolved scales are used to model the contribution of the unresolved scales. However, most of the energy exchanges between scales are local, which means that the energy of the unresolved scales derives mainly from the energy of the small resolved scales. In this fourth chapter, constant-coefficient-based Smagorinsky and WALE models are considered under different formulations. This includes a classical version of both the Smagorinsky and WALE models and several scale-separation formulations, where the resolved velocity field is filtered in order to separate the small turbulent scales from the large ones. From this separation of turbulent scales, the strain rate tensor and/or the eddy viscosity of the subgrid scale model is computed from the small resolved scales only. One important advantage of these scale-separation models is that the dissipation they introduce through their subgrid scale stress tensor is better controlled compared to their classical version, where all the scales are taken into account without any filtering. More precisely, the filtering operator (based on a top hat filter in this work) allows the decomposition u' = u - ubar, where u is the resolved velocity field (large and small resolved scales), ubar is the filtered velocity field (large resolved scales) and u' is the small resolved scales field. At last, two variational multiscale (VMS) methods are also considered. The philosophy of the variational multiscale methods differs significantly from the philosophy of the scale-separation models. Concretely, the discrete Navier-Stokes equations have to be projected into two disjoint spaces so that a set of equations characterizes the evolution of the large resolved scales of the flow, whereas another set governs the small resolved scales. Once the Navier-Stokes equations have been projected into these two spaces associated with the large and small scales respectively, the variational multiscale method consists in adding an eddy viscosity model to the small scales equations only, leaving the large scales equations unchanged. This projection is obvious in the case of a full spectral discretization of the Navier-Stokes equations, where the evolution of the large and small scales is governed by the equations associated with the low and high wavenumber modes respectively. This projection is more complex to achieve in the context of a finite element discretization. For that purpose, two variational multiscale concepts are examined in this work. The first projector is based on the construction of aggregates, whereas the second projector relies on the implementation of hierarchical linear basis functions. In order to gain some experience in the field of LES modeling, some of the above-mentioned models were implemented first in another code called PHASTA and presented along with SFELES in the second chapter. Finally, the relevance of our models is assessed with the large eddy simulation of a fully developed turbulent channel flow at a low Reynolds number under statistical equilibrium. In addition to the analysis of the mean eddy viscosity computed for all our LES models, comparisons in terms of shear stress, root mean square velocity fluctuation and mean velocity are performed with a fully resolved direct numerical simulation as a reference. The fifth chapter of the thesis focuses on the numerical simulation of the 3D turbulent flow over a re-entry Apollo-type capsule at low speed with SFELES. The Reynolds number based on the heat shield is set to Re=10^4 and the angle of attack is set to 180º, that is the heat shield facing the free stream. Only the final stage of the flight is considered in this work, before the splashdown or the landing, so that the incompressibility hypothesis in SFELES is still valid. Two LES models are considered in this chapter, namely a classical and a scale-separation version of the WALE model. Although the capsule geometry is axisymmetric, the flow field in its wake is not and induces unsteady forces and moments acting on the capsule. The characterization of the phenomena occurring in the wake of the capsule and the determination of their main frequencies are essential to ensure the static and dynamic stability during the final stage of the flight. Visualizations by means of 3D isosurfaces and 2D slices of the Q-criterion and the vorticity field confirm the presence of a large meandering recirculation zone characterized by a low Strouhal number, that is St≈0.15. Due to the detachment of the flow at the shoulder of the capsule, a resulting annular shear layer appears. This shear layer is then affected by some Kelvin-Helmholtz instabilities and ends up rolling up, leading to the formation of vortex rings characterized by a high frequency. This vortex shedding depends on the Reynolds number so that a Strouhal number St≈3 is detected at Re=10^4. Finally, the analysis of the force and moment coefficients reveals the existence of a lateral force perpendicular to the streamwise direction in the case of the scale-separation WALE model, which suggests that the wake of the capsule may have some preferential orientations during the vortex shedding. In the case of the classical version of the WALE model, no lateral force has been observed so far so that the mean flow is thought to be still axisymmetric after 100 units of non-dimensional physical time. Finally, the last chapter of this work recalls the main conclusions drawn from the previous chapters.

The accuracy in determined energy consumption and runningtime of trains, by means of computer simulation, is dependent upon the various models used. This thesis aims at developing validated models of running resistance, train and of a generaldriver, all based on full scale testing. A partly new simple methodology for determining running resistance, called by energy coasting method is developed and demonstrated. An error analysis for this methodis performed. Running resistance of high speed train SJ X2000, conventional loco hauled passenger trains and freight trains is systematically parameterised. Influence of speed, number of axles, axle load, track type, train length,and train configuration is studied. A model taking into account the ground boundary layer for determining the influence ofmeasured head and tail wind is developed. Different factors and parameters of a train, that are vital for the accuracy in computed energy consumption and runningtime are identified, analysed and finally synthesized into a train model. Empirical models of the braking and the traction system, including the energy efficiency, are developed for the electrical locomotive of typeSJ Rc4, without energy regeneration. Driver behaviour is studied for freight trains and a couple of driving describing parametersare proposed. An empirical model of freight train driver behaviour is developed from fullscale testing and observations. A computer program, a simulator, is developed in Matlabcode, making use of the determined runningresistance and the developed models of train and driver. The simulator calculates the energy consumption and running time ofa single train. Comparisons between simulations and corresponding measurements are made. Finally, the influence of driving on energy consumption and running time is studied and demonstrated in some examples. The main conclusions are that: The method developed for determining running resistanceis quite simple and accurate. It can be used on any train andon any track. The running resistance of tested trains includes some interesting knowledge which is partly believed to be new. Mechanical running resistance is less than proportional to the actual axle load. Air drag increases approximately linearly with train length and the effect of measured head and tail wind on the air drag can be calculated if the groundboundary layer is considered. The developed train model, including running resistance, traction, braking etc. is quite accurate, as verified for the investigated trains. The driver model together with the train model insimulations, is verified against measurements and shows good agreement for energy consumption and running time. It is recommended to use a driver model, when calculating energy consumption and running times for trains. Otherwise, the energy consumption will most likely be over-estimated.This has been demonstrated for Swedish ordinary freighttrains. / QC 20100526

This doctoral study aims to develop a methodology for use in determining aerodynamic models and parameters from actual flight test data for different types of autonomous flight vehicles. The stepwise regression method and equation error method are utilized for the aerodynamic model identification and parameter estimation. A closed loop aerodynamic parameter estimation approach is also applied in this study which can be used to fine tune the model parameters. Genetic algorithm is used as the optimization kernel for this purpose. In the optimization scheme, an input error cost function is used together with a final position penalty as opposed to widely utilized output error cost function. Available methods in the literature are developed for and mostly applied to the aerodynamic system identification problem of piloted aircraft / a very limited number of studies on autonomous vehicles are available in the open literature. This doctoral study shows the applicability of the existing methods to aerodynamic model identification and parameter estimation problem of autonomous vehicles. Also practical considerations for the application of model structure determination methods to autonomous vehicles are not well defined in the literature and this study serves as a guide to these considerations.

The development of a shape optimization solver using the existing Computational Fluid Dynamics (CFD) codes is taken up as topic of research in this thesis. A shape optimizer was initially developed based on Genetic Algorithm (GA) coupled with a CFD solver in an earlier work. The existing CFD solver is based on Kinetic Flux Vector Splitting and uses least squares discretization. This solver requires a cloud of points and their connectivity set, hence this CFD solver is a meshless solver. The advantage of a meshless solver is utilised in avoiding re-gridding (only connectivity regeneration is required) after each shape change by the shape optimizer. The CFD solver is within the optimization loop, hence evaluation of CFD solver after each shape change is mandatory. Although the earlier shape optimizer developed was found to be robust, but it was taking enoromous amount of time to converge to the optimum solution (details in Appendix). Hence a new evolving method, Ant Colony Optimization (ACO), is implemented to replace GA. A shape optimizer is developed coupling ACO and the meshless CFD solver. To the best of the knowledge of the present author, this is the first time when ACO is implemented for aerodynamic shape optimization problems. Hence, an exhaustive validation has become mandatory. Various test cases such as regeneration problems of (1) subsonic - supersonic nozzle with a shock in quasi - one dimensional flow (2) subsonic - supersonic nozzle in a 2-dimensional flow field (3) NACA 0012 airfoil in 2-dimensional flow and (4) NACA 4412 airfoil in 2-dimensional flow have been successfully demonstrated. A comparative study between GA and ACO at algorithm level is performed using the travelling salesman problem (TSP). A comparative study between the two shape optimizers developed, i.e., GA-CFD and ACO-CFD is carried out using regeneration test case of NACA 4412 airfoil in 2-dimensional flow. GA-CFD performs better in the initial phase of optimization and ACO-CFD performs better in the later stage. We have combined both the approaches to develop a hybrid GA-ACO-CFD solver such that the advantages of both GA-CFD and ACO-CFD are retained with the hybrid method. This hybrid approach has 2 stages, namely, (Stage 1) initial optimum search by GA-CFD (coarse search), the best members from the optimized solution from GA-CFD are segregated to form the input for the fine search by ACO-CFD and (Stage 2) final optimum search by ACO-CFD (fine search). It is observed that this hybrid method performs better than either GA-CFD or ACO- CFD, i.e., hybrid method attains better optimum in less number of CFD calls. This hybrid method is applied to the following test cases: (1) regeneration of subsonic-supersonic nozzle with shock in quasi 1-D flow and (2) regeneration of NACA 4412 airfoil in 2-dimensional flow. Two applications on shape optimization, namely, (1) shape optimization of a body in strongly rotating viscous flow and (2) shape optimization of a body in supersonic flow such that it enhances separation of binary species, have been successfully demonstrated using the hybrid GA-ACO-CFD method. A KFVS based binary diffusion solver was developed and validated for this purpose. This hybrid method is now in a state where industrial shape optimization applications can be handled confidently.