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Performance when gliding in the streamlined position depends on a swimmer’s morphological characteristics, body orientation and water characteristics. The purpose of this thesis was twofold. First to identify and assess the effect of controllable factors that contribute to glide performance and second to form the foundations of an improved approach of simulating the fluid flow around the swimmers’ body. To address the purposes of the thesis four investigations were conducted. Study 1. The effect of the head position on glide performance was investigated. When the high, medium and low head positions were compared, it was found that swimmers experience significantly greater resistance and decelerate faster when they adopt a high head position. It was also found that there is no significant difference between the medium and low head position indicating for the first time that swimmers can choose any of the positions according to their natural tendency. Study 2. The second study examined the effect of gliding depth on gliding performance. A range of depths was investigated ranging from 0.8 m to 0.2 m from the water surface. The results demonstrated significantly higher glide factor values for glides at a greater depth when compared to glides closer to the water surface highlighting the retarding effect of wave drag when gliding close to the surface. The optimum gliding performance was reported for glides at 0.8 m from the surface. Study 3. The third study investigated the effect of full body swimsuits on glide performance. According to the findings, it is demonstrated for the first time that the improved gliding performance when wearing full body swimsuits is linked to changes in swimmers’ morphology due to compression. Study 4. In the fourth study the magnitude of resistive forces applied on a swimmer’s body when gliding underwater was assessed with the use of computational fluid dynamics (CFD) and the LES approach. The results showed a close match between the glide factor values of the experimental and the computational findings demonstrating the effectiveness of the CFD method when the LES approach is employed.

La réduction de la consommation énergétique est actuellement un point important lors de la conception d'un véhicule qu'il soit à moteur thermique (réduction de la consommation d'essence), électrique (augmenter la distance parcourue sans recharger les batteries) ou hybride. C'est dans cette optique que nous chercherons à réduire les forces de traînée aérodynamique qui s'opposent au mouvement de tout véhicule et qui sont donc à l'origine d'une consommation supplémentaire d'énergie. Grâce au développement des outils de calcul, il est aujourd’hui possible de tester sans fabriquer. En effet, grâce à l’essor de la CFD (Computational Fluid Dynamics) il est désormais possible de reproduire tous nos bancs de tests et nos optimisations de façon numérique. Cependant, ces outils ne sont pas encore parfaits et ils nécessitent des ajustements obtenus grâce à la mise en place de tests expérimentaux. C’est ainsi que les caractérisations et optimisations effectuées sur le tricycle hybride étudié et ses sous-systèmes seront réalisées. L'étude portera principalement sur l'aérodynamique externe du tricycle ainsi que sur ses échangeurs thermiques.

In order to eliminate or reduce vibration problems inturbomachines without a high increase in the complexity of thevibratory behavior, the adjacent airfoils around the wheel areoften mechanically connected together with lacing wires, tip orpart-span shrouds in a number of identical sectors. Although anaerodynamic stabilizing effect of tying airfoils together ingroups on the whole cascade is indicated by numerical andexperimental studies, for some operating conditions suchsectored vane cascade can still remain unstable. The goal of the present work is to investigate thepossibilities of a sectored vane cascade to undergoself-excited vibrations or flutter. The presented method forpredicting the aerodynamic response of a sectored vane cascadeis based on the aerodynamic work influence coefficientrepresentation of freestanding blade cascade. The sectored vaneanalysis assumes that the vibration frequency is the same forall blades in the sectored vane, while the vibration amplitudesand mode shapes can be different for each individual blade inthe sector. Additionally, the vibration frequency as well asthe amplitudes and mode shapes are supposed to be known. The aerodynamic analysis of freestanding blade cascade isperformed with twodimensional inviscid linearized flow model.As far as feasible the study is supported by non-linear flowmodel analysis as well as by performing comparisons againstavailable experimental data in order to minimize theuncertainties of the numerical modeling on the physicalconclusions of the study. As has been shown for the freestanding low-pressure turbineblade, the blade mode shape gives an important contributioninto the aerodynamic stability of the cascade. During thepreliminary design, it has been recommended to take intoaccount the mode shape as well rather than only reducedfrequency. In the present work further investigation using foursignificantly different turbine geometries makes these findingsmore general, independent from the low-pressure turbine bladegeometry. The investigation also continues towards a sectoredvane cascade. A parametrical analysis summarizing the effect ofthe reduced frequency and real sector mode shape is carried outfor a low-pressure sectored vane cascade for differentvibration amplitude distributions between the airfoils in thesector as well as different numbers of the airfoils in thesector. Critical (towards flutter) reduced frequency maps areprovided for torsion- and bending-dominated sectored vane modeshapes. Utilizing such maps at the early design stages helps toimprove the aerodynamic stability of low-pressure sectoredvanes. A special emphasis in the present work is put on theimportance for the chosen unsteady inviscid flow model to bewell-posed during numerical calculations. The necessity for thecorrect simulation of the far-field boundary conditions indefining the stability margin of the blade rows isdemonstrated. Existing and new-developed boundary conditionsare described. It is shown that the result of numerical flowcalculations is dependent more on the quality of boundaryconditions, and less on the physical extension of thecomputational domain. Keywords: Turbomachinery, Aerodynamics,Unsteady CFD, Design, Flutter, Low-Pressure Turbine, Blade ModeShape, Critical Reduced Frequency, Sectored Vane Mode Shape,Vibration Amplitude Distribution, Far-field 2D Non-ReflectingBoundary Conditions. omain. Keywords:Turbomachinery, Aerodynamics, Unsteady CFD,Design, Flutter, Low-Pressure Turbine, Blade Mode Shape,Critical Reduced Frequency, Sectored Vane Mode Shape, VibrationAmplitude Distribution, Far-field 2D Non-Reflecting BoundaryConditions.

The main objectives of this study were to obtain new experimental data for conditions not previously tested for discharging two-phase flow through two 6.35 mm diameter branches with centrelines falling in an inclined plane and to assess the applicability of ANSYS CFX in modelling discharging two-phase flow through various single and multiple branch geometries. The present results are relevant to many industrial applications including headers and manifolds, multichannel heat exchangers and small breaks in horizontal pipes. In the experimental investigation, onsets of liquid and gas entrainment data were obtained, analyzed and correlated for two different branch spacings and two different angles between the branches. For each combination of branch spacing and angle between the branches, a wide range of Froude numbers was used. Two-phase mass flow rate and quality results were also obtained and analyzed for a range of interface heights for 16 different combinations of branch spacing, inclination angle, test section pressure and pressure drop across each branch. New correlations were developed to predict the dimensionless mass flow rate and the quality. The new correlations show good agreement with the present data and with previous correlations. Using ANSYS CFX, the inhomogeneous, free surface model was used to model discharging two-phase flow through horizontal branches with the following configurations: a single short branch of square cross-section (G1), a single long branch of square cross-section (G2), a single long branch of round cross section (G3), two round branches located one on top of the other (G4), and two round branches with their centreplane angled 30° from the horizontal. For these five geometries, results were compared with previous and present results and showed good agreement for Geometries G1, G2, G3 and G5. For Geometry G4, CFX was unable to predict results when the interface was located such that the two phases flowed through both branches simultaneously. Under these conditions, the flow phenomena were too complicated and further investigations are necessary. / February 2017

Increase in urbanization and industrialization around the world in recent years has led to a consequent rise in energy demand. In recent years it has been reported that approximately 75% of generated power is consumed in cities. It also worth to mention that about 50% energy consumption in U.S is in building sector which 41.7% is for operating buildings. With the global energy demand in 2040 being expected to be about 30% higher than that of 2010. For this reasons, an urgent need for the incorporation of alternative energy as well as energy efficiency measures has to be incorporated in urban planning and construction. Until now, two main approaches that have been integrated into large scale wind energy in urban settings are either locating wind energy farm in the periphery of the urban areas or integration of wind energy systems into the building design. It was observed that the installation of wind turbines in order to meet 10–15% of global energy demand might cause surface warming by increasing the temperature by 1 °C on land. Moreover, there some issues that can be considered as a disadvantage for large wind turbines. For Instance: noise production, the social aesthetic acceptability, negative impact on birds, the cost of maintenance, transportation, sufficient infrastructure and etc. In contrast to large-scale wind turbines, small wind turbines are much simpler and exploitation of building. In high-rise buildings, the heights and onsite energy generation imply an absence of big towers required to capture high wind speeds and minimum transmission losses, as well as a contribution to the configuration of zero-energy buildings. On the other hand, to improve safety and serviceability of super-tall buildings in strong winds, aerodynamic optimization of building shapes is considered to be the most efficient approach. Aerodynamic optimization is aimed at increasing the structural resistance against winds. The idea of generating wind power in high rise buildings is experienced in some constructions that the further study reveals the cons and pros about them. The Pearl River Tower, which is one of the latest and successful building in this type, considered as the case study for this research. The research proposing the distributed opening as an effective modification to improve the aerodynamic behavior of the high rise buildings and devising the micro-turbine within the penetration for wind energy generating. The CFD simulation shows the improvement in coefficient drag factor in the proposal design option and the wind tunnel test reveals better aerodynamic performance as well. The conclusion shows better performance for wind harvesting and wind energy generating beside reducing the structural weight that would be needed in comparison to the original building. On the other hand, the proposal design shows more lift forces on the building and the other challenging issue would be maintenance the higher number of the small turbine. The further study will be needed to controlling the vibration and noise level inside the wind ducts and optimizing the wind penetration pattern on the building façade.

Pharmaceutical aerosols provide a number of advantages for treating respiratory diseases that include targeting high doses directly to the lungs and reducing exposure of other organs to the medication, which improve effectiveness and minimize side effects. However, difficulties associated with aerosolized drug delivery to the lungs include drug losses in delivery devices and in the extrathoracic region of human upper airways. Intersubject variability of extrathoracic and thoracic drug deposition is a key issue as well and should be minimized. Improvements to respiratory drug delivery efficiency have been recently proposed by Dr. P. Worth Longest and Dr. Michael Hindle through the use controlled condensational growth methods, which include enhanced condensational growth (ECG) and excipient enhanced growth (EEG). These methods reduce inhaled drug loss through the introduction of an aerosol with an initial submicrometer aerodynamic diameter, which then experiences condensational growth to increase droplet size and enhance thoracic deposition. Tracheobronchial and nasal human airway computational models were developed for this study to assess drug delivery using conventional and EEG methods. Computational versions of these models are used to assess drug delivery and variability with computational fluid dynamics (CFD) simulations, which are validated with experimental data where possible. Using CFD, steady state delivery of albuterol sulfate (AS) during high flow therapy (HFT) through a nasal cannula was characterized with four nasal models developed for this study, with results indicating an increase in average delivered dose from 24.0% with a conventional method to 82.2% with the EEG technique and an initially sized 0.9 µm aerosol, with a corresponding decrease in the coefficient of variation from 15% to 3%. Transient CFD simulations of nebulized AS administration through a mask during noninvasive positive pressure ventilation (NPPV) were performed and validated with experimental data, which resulted in 40.5% delivered dose with the EEG method as compared with 19.5% for a conventional method and a common inhalation profile. Using two newly created face-nose-mouth-throat models, dry powder delivery of ciprofloxacin during NPPV was assessed for the first time with steady state CFD predictions, which showed an increase in average delivered lung dose through a new mask design of 78.2% for the EEG method as compared with 36.2% for conventional delivery, while corresponding differences in delivered dose between the two models were reduced from 45.4% to 12.8% with EEG. In conclusion, results of this study demonstrate (i) the use of highly realistic in silico and in vitro models to predict the lung delivery of inhaled pharmaceutical aerosols, (ii) indicate that the EEG approach can reduce variability in nose-to-lung aerosol delivery through a nasal cannula by a factor of five, and (iii) introduce new high efficiency methods for administering aerosols during NPPV, which represents an area of current clinical need.

The aim of this work was to use experimental, analytical and computational Computational Fluid Dynamic - CFD methodologies to investigate so-called highly transient axi-symmetric squeeze flows. These flows occur between two co-axial and parallel discs which are subjected to an impact, arising from a falling mass, which induces a constant energy squeezing system, as distinct from the traditionally investigated constant force or constant velocity squeezing systems. Experiments were conducted using a test cell comprising two parallel discs of diameter 120 mm with a flexible bladder used to contain fluid. This test cell was bolted onto the base of a drop-weight tester used to induce constant energy squeeze flows. Glycerine was used as the working fluid, the temperature of which was appropriately monitored. Disc separation, together with pressures at three radial positions, were measured throughout the experimental stroke typically less than 10 ms duration. Two additional pressure transducers at the same radial position as the outermost transducer were also used to monitor and subsequently correct for minor non-axi-symmetries that arose in the system. Approximately 150 tests were conducted, embracing combinations of drop height from 0.1 to 1 m, drop mass from 10 to 55 kg and initial disc separation from 3 to 10 mm. Three elementary features were typically observed: a distinct preliminary pressure spike 1 immediately after impact corresponding to very large accelerations exceeding over 6 km/s2 in some experiments, a secondary major pressure spike 2 towards the termination of the stroke corresponding to diminishing disc separations and a bridging region 3 joining the two spikes corresponding to somewhat reduced pressures. While pressure distributions were observed to be closely parabolic during the major pressure spike, some uncertainty was present during the preliminary pressure spike, ascribed to sensitivities to deviations from axi-symmetry, and the likelihood of inertially generated pressures at the edge of the disc. The former feature appears not to have been reported on in the formal literature. iii Four analytical models were considered, invoking the parallel flow assumption in conjunction with the Navier Stokes equations: an inviscid/inertial model, a viscous model the lubrication approximation, a quasi-steady linear QSL model and a quasi-steady corrected linear QSCL model. The first two of these models, on incorporation of measured disc separations, and the derived velocities and accelerations, achieved acceptable correlations with pressure measurements largely within uncertainty bounds during the initial impact and towards the end of the stroke, respectively. The QSL model agreed satisfactorily with measurements throughout the entire duration of the experiment, while the QSCL model, by incorporating non-linear effects in an approximate linear way, yielded somewhat better correlations. By invoking the parallel flow assumption, all four models predict a parabolic radial pressure distribution. Utilizing a hypothetical case in which variations of disc separation, velocity and acceleration were considered employing similar magnitudes and timescales to those that were measured, outputs of the QSL model yielded results that correlated closely with CFD predictions, while the QSCL data were somewhat better. On the basis of the CFD data it was also inferred that, within practical uncertainty bounds, the parallel flow assumption was valid for the range of disc separation to radius ratios embraced in the current investigation.