A study of impulsively started flow over cylindrical objects is made using the particle image velocimetry (PIV) technique for Reynolds numbers of Re = 200, 500 and 1000 in an X-Y towing tank. The cylindrical objects studied were a circular cylinder of diameter, D = 25.4 mm, and square and diamond cylinders each with side length, D = 25.4 mm. The aspect ratio, AR (= L/D) of the cylinders was 28 and therefore they were considered infinite. The development of the recirculation zone up to a dimensionless time of t* = 4 following the start of the motion was examined. The impulsive start was approximated using a dimensionless acceleration parameter, a*, and in this research, the experiments were conducted for five acceleration parameters, a* = 0.5, 1, 3, 5 and 10. The study showed that conditions similar to impulsively started motion were attained once a* ¡Ý 3.<p> A recirculation zone was formed immediately after the start of motion as a result of flow separation at the surface of the cylinder. It contained a pair of primary eddies, which in the initial stages (like in this case) were symmetrical and rotating in opposite directions. The recirculation zone was quantified by looking at the length of the zone, LR, the vortex development, both in terms of the streamwise location and the cross-stream spacing of the vortex centers, a and b, respectively, as well as the circulation (strength) of the primary vortices, ¦£.<p> For all types of cylinders examined, the length of the recirculation zone, the streamwise location of the primary eddies and the circulation of the primary eddies increase as time advances from the start of the impulsive motion. They also increase with an increase in the acceleration parameter, a*, until a* = 3, beyond which there is no more change, since the conditions similar to impulsively started conditions have been achieved. The cross-stream spacing of the primary vortices is relatively independent of Re, a* and t* but was different for different cylinders.<p> Irrespective of the type of cylinder, the growth of the recirculation zone at Re = 500 and 1000 is smaller than at Re = 200. The recirculation zone of a diamond cylinder is much larger than for both square and circular cylinders. The square and diamond cylinders have sharp edges which act as fixed separation points. Therefore, the cross-stream spacing of the primary vortex centers are independent of Re, unlike the circular cylinder which shows some slight variation with changes in Reynolds number.<p> The growth of the recirculation is more dependent on the distance moved following the start of the impulsive motion; that is why for all types of cylinders, the LR/D, a/D and ¦£/UD profiles collapse onto common curves when plotted against the distance moved from the start of the motion.

ALe travail réalisé dans le cadre de cette thèse en co-tutelle est à cheval entre deux domaines d’étude de l’interférence de sillage d’obstacle non profilé (soit un cylindre ou deux cylindres en tandem) et celle des zones de recirculations dans un sluice artisanal (un appareil de tri d’or). Notre étude contribue à l’étude des écoulements à surface libre par combinaison de quelques méthodes expérimentales. Nous avons couplé quelques techniques entre autres la visualisation de la topologie du sillage proche par la caméra CCD embarquée, les mesures des champs de vitesse par PIV et des efforts hydrodynamiques. Ainsi, le cylindre animé d’un mouvement uniformément accéléré/décéléré est caractérisé par les forces de traînée et de portance, les enveloppes des maximas, la longueur de le zone de recirculation et le nombre de Strouhal local. Dont ce dernier a une valeur avoisinant de 0.4 près de la surface libre. Et entre deux pics de la portance, le déferlement de la vague d’accompagnement est observable. L’interférence entre deux structures est simulée à travers deux cylindres et que sur une configuration symétrique, le paramètre de proximité B a tendance à accroître la longueur de la zone de recirculation. Les méthodes et dispositifs expérimentales décrites ci-dessus sont appliqués dans le cas d’écoulement hydrodynamique turbulent au sein du sluice. Les essais sur sites aurifères à Madagascar ont permis la collecte des informations sur les paramètres optimums du tri. Ces paramètres sont pris comme base initiale des travaux de laboratoire entamés sur une maquette à l’échelle 1. L’acquisition par PIV suivi des traitements statistique à multi-variables POD Snapshot nous a permis de créer un modèle expérimental de l’écoulement composé de 4 zones distinctes. L’étude expérimentale a été complétée par une simulation numérique par ANSYS14.5 ; qui nous a permis de conclure que l’approchement des riffles entraîne une diminution de la zone favorable du dépôt des minerais lourds. / Two major areas are focused in the thesis. The first investigates the interference due to a wake-pattern of non-profiled obstacles (such as one or two cylinder in tandem). The second characterizes the zone of recirculation inside an artisanal sluice-boxe, which is a device for gold extraction. The work contributes to the study of the flow of a free-surface using experimental methods. Also, a few approaches is combined for the investigation. In this regard, the near-wake pattern of the flow is examined using an embedded CCD camera, correlated to a PIV measurement of the velocity fields and the hydrodynamic forces. We found that a cylinder of uniform motion, accelerated or decelerated, is characterized by: the drag and the lift forces, the envelopes of maxima, the length of the recirculation zone and the local Strouhal number. The Strouhal number approaches the value of 0.4 next to a free-surface and a breaking wave is observed in-between two peaks of the lift force. We modeled the interference between two structures using a succession of two cylinders. The proximity parameter B tends to an increase of the recirculation length for a symmetrical arrangement.Our methods and the experimental procedures are applied for the examination of a turbulent hydrodynamic flow inside a sluice. Tests were performed on gold sites in Madagascar. This permitted the collection of information concerning the optimum parameters for an extraction. The obtained values form the basis of our laboratory work and are applied to a scaled model for validation. An experimental flow model, made of four distinct zones, is derived from a monitored PIV data and a statistical analysis of a multi-variable POD snapshot. The results are validated through simulations using the package ANSYS 14.5. The investigation shows that a closer riffles reduces the region for heavy minerals deposition.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Os potenciais impactos ambientais provenientes da aquicultura intensiva tÃm aumentado a preocupaÃÃo da sociedade quanto à sustentabilidade da prÃpria atividade. Com o presente trabalho teve como objetivo avaliar, os parÃmetros zootÃcincos das tilÃpias do Nilo, qualidade de Ãgua, produÃÃo de biomassa algal e taxa de remoÃÃo dos compostos nitrogenados pela microalga Spirulina platensis em um cultivo integrado da tilÃpia do Nilo (Oreocrhomis niloticus) com a microalga S. platensis em um sistema fechado de circulaÃÃo de Ãgua. O experimento foi realizado no Centro de Biotecnologia Aplicada a Aquicultura (CEBIAQUA) do Departamento de Engenharia de Pesca da Universidade Federal do CearÃ. O cultivo das tilÃpias foi inteiramente casualizado e realizado em trÃs tratamentos com quatro repetiÃÃes nas densidades de 0,1; 0,15 e 0,20 juvenis L-1. As tilÃpias foram alimentadas ad libitum com raÃÃo comercial (0.8 mm), contendo 55% de proteÃna bruta (PB), fornecida Ãs 9, 13 e 17 h, sete dias por semana. Para o cultivo de Spirulina platensis, inicialmente, o inÃculo foi cultivado em meio quÃmico alternativo e posteriormente adaptado ao efluente de tilÃpia do Nilo e inoculado em 12 bacias de polietileno. Durante todo o experimento, a Ãgua das caixas dos peixes e das respectivas bacias das microalgas foi reutilizada no sistema de recirculaÃÃo fechado entre as duas culturas, havendo apenas reposiÃÃo de Ãgua por conta da evaporaÃÃo. ApÃs o completo desenvolvimento da S. platensis nas bacias, a coleta da microoalga foi realizada atravÃs de filtragem da Ãgua em telas de 60 Âm. Foram ainda monitorados o pH, temperatura, oxigÃnio dissolvido, bem como determinados os nÃveis de N-amÃnia, N-nitrato e N-nitrito durante o perÃodo experimental. Os resultados mostraram que a densidade de estocagem mais eficiente para o cultivo das tilÃpias foi 0,10 juvenis L-1, pois apesar de ter resultado na mesma biomassa final dos demais tratamentos, foi a que apresentou a menor taxa de conversÃo alimentar. A microalga S. platensis se adaptou facilmente e se desenvolveu muito bem no efluente das tilÃpias do Nilo, independente da densidade de estocagem dos peixes. Com relaÃÃo à qualidade de Ãgua, foi evidenciado que a integraÃÃo das culturas manteve os nÃveis de N-amÃnia (0,26  0,03 mg L-1), N-nitrato (2,55  0,71) e N-nitrito (0,19  0,01) dentro dos valores aceitÃveis para o cultivo da tilÃpia do Nilo. / The environmental potential impacts from intensive aquaculture have increased public concern about the sustainability of the activity itself. The present work aimed to evaluate the zootÃcincos parameters of Nile tilapia , water quality, algal biomass production and rate of nitrogen removal compounds by Spirulina platensis realize an integrated cultivation of Nile tilapia (Oreocrhomis niloticus) with Spirulina platensis in a closed system of water circulation. The experiment took place at the Biotechnology Aquaculture Applied Center (CEBIAQUA) of The Fishing Engineering Department of the Federal University of CearÃ. Tilapias culture was conducted in three treatments with four replicates at densities of 010, 0,15 and 0,20 juveniles L-1. The tilapias were fed ad libitum with a commercial ration (0,8 mm) containing 55% crude protein (CP), administered daily at 9, 13 and 17 h. For Spirulina platensis culture, initially, the inoculum was cultivated in an alternative chemical medium and later adapted to the Nile tilapia effluent and inoculated into 12 polyethylene basins. Throughout the experiment, the water of fishes boxes and of the respective microalgae basins was reused in the closed recirculation system between the two cultures, with only replacement of water due to evaporation. After the full development of S. platensis in the basins, the microalgae was collected using a 60 Âm screen. The pH, temperature, dissolved oxygen, and levels of N-ammonia, N-nitrate and N-nitrite were also monitored during all the experimental period. The results showed that the most efficient stocking density was 0,10 L-1, because despite having the same final biomass of the other treatments it presented the lowest feed conversion ratio. The microalgae S. platensis was easily adapted and developed very well in the Nile tilapiaâs effluent, regardless of fishes stocking density. With respect to water quality, it was evident that the cultures integration maintained the levels of N-ammonia (0,26  0,03 mg L-1), N-nitrates (2,55  0,71 mg L-1) and N- nitrites (0,19  0,01 mg L-1) within acceptable values for the Nile tilapia culture.

<p>The primary objective of this research was to shed light on the changes in performance observed in a high-speed, centrifugal compressor that occur during the transition from subsonic to transonic operating conditions, using experimental data collected on a research compressor developed by Honeywell Aerospace, as well as results from a numerical model of the compressor.</p> <p> An understanding of the flow behavior in transonic centrifugal compressors is critical as the drive for higher stage pressure ratios while maintaining a compact size results in higher rotational speeds and increased aspect ratios in the inducer of the impeller. Both of these design trends result in higher relative Mach numbers near the impeller leading edge, resulting in the formation of shocks and an increasingly complex flow field. Since it is necessary to maintain high efficiency and adequate surge margin at these conditions—to ensure the compressor is stable across the full operating range—it is important to understand the effects of the transition from subsonic to supersonic flow on performance and stability. Due to the limited availability of research in the open literature regarding transonic centrifugal impellers, especially experimental studies, these behaviors are still not fully understood.</p> <p>Experimental data collected during steady state operation as well as during speed transients, showed a sudden decrease in the variance of the unsteady pressure field throughout the compressor, but most dramatically in the inducer shroud. Analysis of the performance also showed a significant increase in impeller efficiency of approximately 2 points as speed was increased from 80% to 90% of the design speed. Temperature measurements upstream of the impeller leading edge indicated a dramatic reduction in the degree of flow recirculation in the same speed range, indicating the increase in performance is related to a decrease in the blockage near the impeller leading edge. A low pressure region was also observed in the inducer passage, which disappeared upon transition to the transonic operating regime, this coupled with decreased inducer static pressure rise and relative diffusion at lower speeds, strongly indicates that increased loss in the inducer at lower speeds is responsible for the observed performance deficiency during subsonic operation.</p> <p>Analysis of the numerical results revealed that the low pressure region in the inducer may be attributable to the interaction between the inlet shroud boundary layer and the low momentum tip leakage flow in the impeller passage, which at lower speeds, results in the tip leakage flow forming a large recirculation region in the inducer passage. It was also determined that the step change in instability coincides with the inducer shock extending to the shroud and reducing the strength of the interaction between the low momentum regions in the inlet and impeller passage, thereby allowing the tip leakage flow to form into a vortex and preventing the development of the recirculation region in the inducer. </p> <p>This research provides a possible explanation for the observed instability in the compressor, which may allow for further testing of techniques to mitigate the instability caused by the blockage in the inducer, such as casing treatment, bleed, or flow injection into the inducer shroud.</p>

Purpose: Use of ampicillin in outpatient parenteral antimicrobial therapy (OPAT) has historically been complicated by frequent dosing and short beyond use dates. However historic stability data relied on inaccurate testing methods. The purpose of this study is to evaluate the stability of ampicillin using high-pressure liquid chromatography (HPLC), the gold standard, in a real-world OPAT dosing model using continuous infusion at room temperature over 24 hours immediately following preparation compared to batches stored under refrigeration for 24 hours, 72 hours, and 7 days. Methods: An HPLC method was developed and validated as stability – indicating according to guidance in USP general Chapter < 1225 >. Method development included linearity, precision, accuracy, repeatability and forced degradation. Four batches were prepared using 4 different lots from 2 different manufacturers for each storage condition (immediate, 24 hours, 72 hours, and 7 days). Three 2-gram vials were each reconstituted with 10 mL of sterile water for injection (SWFI) and added to 250 mL of normal saline by a licensed pharmacist and stored in a laboratory refrigerator (2 – 8oC). A pump system was used to continuously circulate the solutions through medical grade tubing at room temperature. One milliliter aliquots were removed from each batch at time 0, 4 hours, 8 hours, 12 hours and 24 hours and analyzed for ampicillin concentration using the aforementioned HPLC method. The samples were filtered prior to analysis using a 0.22-micron syringe filter and analyzed in triplicates along with freshly prepared calibration samples (24 – 12 mg/mL). Peak area was used to determine percent recovery for each sample. Results:Each batch was assayed for initial concentration (20.34 – 21.50 mg/mL) upon preparation, and percent recovery was compared to that initial concentration thereafter. Acceptable recovery was defined as 90 – 110% of initial concentration. On the day of product preparation (immediate use), the average percent recovery over 24 hours was 96.4%. The other average percent recoveries were as follows: 95.8% (24-hour storage), 94.6% (72-hour storage) and 90.3% (7-day storage). These data represent the average percent recovery for all time points during the 24 hours sampling (n = 60 for each experiment). When evaluating individual time points, the percent recovery remained above 90% for all batches and time points except for the 7-day storage experiment. Under 7-day storage conditions, the percent recovery fell below 90% after 4 hours of circulation through the medical grade tubing. Furthermore, 95% confidence interval for percent recovery for ampicillin in the samples stayed within 90 – 110% of the initial concentration for the duration of the experiment for all test groups except 7-day storage. Conclusion:Ampicillin can be prepared and stored in a refrigerator for up to 72-hours prior to continuously infusing at room temperature over 24 hours with less than a 10% loss of potency over the dosing period. This model supports twice weekly OPAT delivery of ampicillin.

No description available.

Les piles à combustible PEM sont des systèmes complexes faisant intervenir de nombreux auxiliaires. Ces auxiliaires ont un impact sur le rendement global du système. Une des possibilités pour améliorer le rendement global du système est d'améliorer le rendement de ces auxiliaires et notamment celui du système de recirculation d'hydrogène.Le système de recirculation d'hydrogène permet à la fois l'apport de l'hydrogène à l'anode mais il permet également de gérer l'eau présente. Deux solutions sont proposées pour modifier le système de recirculation.La première solution utilise la consommation d'hydrogène à l'anode comme une pompe à vide permettant alors grâce à l'ouverture et à la fermeture cyclique d'une électrovanne, la mise en mouvement du gaz dans la boucle de recirculation. La deuxième solution consiste à utiliser un stack de pile à combustible comme une pompe à hydrogène qui s'intègre alors dans une boucle de recirculation classique.Ces deux solutions ont été étudiées analytiquement, numériquement (MATLAB©, SIMULINK©) et expérimentalement.La première solution a montré sa capacité à se substituer à un système de recirculation à pompe classique en ayant des performances de recirculation et une compacité équivalente mais surtout en améliorant le rendement global du système pile de 2.5% à sa puissance nominale.La seconde solution a montré une bonne capacité à gérer la recirculation d'hydrogène et sa spécificité de pompage de l'hydrogène seul ouvre la possibilité à de nombreux autres systèmes. / PEM fuel cells are complex systems involving many auxiliaries. These auxiliaries have an impact on the overall system performance. One possibility to improve the overall performance of the system is to improve the performance of these auxiliaries and in particular the system of hydrogen recirculation.The hydrogen recirculation system allows both the supply of hydrogen to the anode but also the management of the water present within the system. Two solutions are proposed to modify the recirculation system.The first solution uses the hydrogen consumption at the anode as a vacuum pumping mechanism used as the motive power of the recirculation loop. The second solution uses a fuel cell stack as a hydrogen pump which is then integrated into a conventional recirculation loop.Both solutions have been studied analytically, numerically (MATLAB ©, SIMULINK ) and experimentally.The first solution has demonstrated its ability to replace a conventional recirculation pump having equivalent recirculation performances and an equivalent compactness. It permits to improve the overall performance of the fuel cell by 2.5% at nominal power.The second solution has shown a good ability to manage the hydrogen recirculation. Its specificity to solely pump hydrogen opens up the possibility of many other systems. Anodic gases purification appears to be highly promising.

Dans un procédé de séchage, l'évacuation de l'eau induit des modifications structurelles et physicochimiques qui engendrent des difficultés d'écoulement dans le séchoir. Cette étude a porté sur la modélisation du séchage continu par contact avec agitation. Nous avons développé un modèle markovien pour décrire les transferts de masse, de chaleur et l'écoulement dans un séchoir continu. Les paramètres d'entrée du modèle ont été déterminés expérimentalement sur un produit pâteux, tandis que d'autres paramètres ont été obtenus à partir de la littérature scientifique. L'étude de sensibilité de la teneur en eau et de la masse sèche retenue dans le séchoir a permis d'analyser et de hiérarchiser les effets des différentes variables opératoires. Enfin, nous avons étudié l'influence des variables opératoires sur le profil de teneur en eau, le temps de passage et les courbes de distribution de temps de séjours simulées. L'évolution structurelle du produit a été mise en évidence dans le modèle. / In a drying process, the evacuation of water induced structural and physico-chemical modifications that generate difficulties of flow in the dryer. This study focused on the modeling of agitated indirect continuous dryer. We developed a Markov model to describe the mass transfer, heat transfer and flow in a continuous dryer. The input parameters of the model were determined experimentally on a pasty product, while other parameters were obtained from the scientific literature. The sensitivity study of the moisture content and dry mass retained in the dryer was used to analyze and treat on a hierarchical basis the effects of different operating variables. Finally, we studied the influence of variables operating on the profile of moisture content, the passage time and the simulated curves of residence time distribution. The structural evolution of the product was considered in the model

Une « boue » est constituée de particules submillimétriques immergées dans un fluide. Nous étudions des boues concentrées (ou « pâtes granulaires »), où la concentration en particules est proche du maximum réalisable. Les particules peuvent être plus denses que le fluide, et sédimenter, ou être équilibrées en densité. Ces deux cas sont examinés, à l’aide d’une boue modèle. Nous étudions les écoulements de ces boues dans une cellule de Couette. Les expériences utilisent des méthodes innovantes, permettant de mesurer les vitesses des grains individuellement et collectivement, et les profils de concentration sous cisaillement. Les expériences apportent des informations nouvelles sur les écoulements, comme l’existence de courants de re-circulation. Les résultats sur les vitesses azimutales et concentrations sont en accord avec la théorie de Morris et Boulay d’équilibre des forces normales, pour un rapport convenable des coefficients viscométriques des forces tangentielle et normales. / Wet granular materials are made of solid particles in high concentration, immersed in a viscous fluid. We investigated particle dynamics in a model granular suspension in Couette geometry, at low Reynolds/Taylor numbers for density and non density matched suspension. We used innovated techniques such as: Single Particle Tracking (SPT), Multi Particles Video Trajectography (MPVT) and Concentration Photometry (CP). These experiments allow us to provide information about single and collective motion of grains as well as particle repartition (local volume fraction). We investigated fully 3D velocity profiles in concentrated suspensions, diffusion coefficients, particle fluctuations and recirculation motion, also differential flows. We observe that the flow of non density matched suspensions is localized near the inner cylinder in the low shear rate regime, resulting in a sheared layer only a few particle diameters in thickness, in a way very similar to sheared dry granular materials. At high enough angular velocity, the initially localized flow crosses over to full fluidization: in this regime the granular suspension nearly behaves as a density-matched suspension. Dependence between particles’ velocity and associated fluctuation amplitude is evidenced. Experiments as velocity and concentration profiles were compared with theoretical prediction based on the force balance model and different viscometric laws were investigated for normal and shear forces.

Afin de mieux comprendre les mécanismes liés à l’érosion du sol sous l’effet du vent, le transport de particules solides dans un écoulement de couche limite turbulente à l’échelle d’une soufflerie est étudié à l’aide de simulations numériques. La présence d’une ou plusieurs collines Gaussiennes au sol permet d’étudier les effets de la topographie sur le transport, le dépôt et la réémission de particules solides. L’écoulement du fluide porteur est résolu par la Simulation des Grandes Échelles (SGE). Des modèles de paroi pour la vitesse du fluide sont implémentés afin de mieux représenter l’écoulement proche d’une colline. Le mouvement des particules est pris en compte par un suivi Lagrangien. Des modèles d’envol et de rebond sont développés et utilisés pour prendre en compte l’émission et l’impact au sol des particules. Dans la première partie, l’écoulement au-dessus de collines transversales est simulé et validé par des comparaisons avec différentes expériences. Selon Oke [1988], l’écoulement dans la canopée urbaine peut être schématiquement caractérisé par différents régimes en fonction du positionnement relatif des obstacles. Ce concept est appliqué au cas des dunes, assimilées à des collines dans notre étude. L’accent est mis sur la zone de recirculation (ZR) formée derrière ces collines. Les variations de la ZR sont examinées en fonction de différents paramètres dont la configuration des collines et le nombre de Reynolds. De plus, une étude portant sur la sous couche rugueuse est effectuée de façon à déterminer l’effet de la rugosité due à la couche de particules solides au sol. La seconde partie du travail porte sur la simulation des particules au-dessus des collines. L’objectif est l’amélioration des modélisations concernant l’envol, le rebond et le couplage entre le fluide et les particules. Un premier travail de validation est réalisé en utilisant le modèle complet de transport des particules solides. En particulier, l’évolution du flux d’émission des particules, estimé par le modèle d’envol, en fonction du nombre de Shields, donne des résultats comparables aux modèles classiques de saltation et aux expériences de la littérature. Au-dessus des collines, le transport des particules solides est étudié par des profils de concentration et de vitesse moyenne. Pour analyser les résultats, deux cartographies sont réalisées. La première donne l’intensité des événements locaux et instantanés qui seraient à l’origine de l’évacuation des particules piégées au sein de la ZR. La seconde montre la distribution des particules déposées au sol. Ces résultats permettent d’identifier des zones sujettes à l’érosion et à l’accumulation autour des collines. Enfin, les flux des particules piégées et déposées à l’intérieur de la ZR sont quantifiés et comparés aux flux des particules émises en amont. Ces flux, bien que faibles par rapport au flux entrant, contribueraient aux migrations des dunes et à l’avancée des déserts. / The transport of solid particles inside a laboratory-scale turbulent boundary-layer is studied by numerical simulations, to obtain a better understanding of the mechanisms associated with wind erosion of soil. The presence of one or several Gaussian hills allows a study of the topographic effects on the transport, deposition and re-emission of solid particles. The carrier fluid motion is resolved in a Large Eddy Simulation (LES). Wall models are implemented to better account for the effects of turbulent flow near the terrain. Particle trajectories are calculated using a Lagrangian tracking. Take-off and rebound models are developed in order to take into account particle emissions and impacts at the wall. In the first part, the flow over transversal Gaussian hills is simulated and validated by comparison with different experiments. According to Oke [1988], the flow inside an urban canopy can be schematically characterised into different flow regimes depending on the relative localisation of the obstacles at the ground. This concept is applied to the case of sand dunes, assimilated to 2D hills in this study. The focus is on the recirculation zone (RZ) on the lee side, which has the characteristic of increasing the residence time and the interaction fluid/particle in general, particle trapping and deposition in particular. The variations of RZ with different hill geometries and Reynolds numbers are examined. A study on the roughness sublayer is conducted in order to determine the roughness effects due to the layer of solid particles on the wall. The second part of the work is devoted to the simulation of solid particle transport over the Gaussian hills. The objective is to improve the modelling of particle take-off, rebound and the two-way coupling between the fluid and the particle. A first work of validation is conducted by using the complete model of solid particle transport developed in this thesis. In particular, the evolution of particle emission flux predicted by the take-off model is in accordance with classical saltation models and experiments from the literature. Over the Gaussian hills, analysis of particle transport is conducted using concentration and mean velocity fields. Two mappings are realised. The first indicates the intensity of the local and instantaneous flow structures that arguably regulate the re-entrainment of particles trapped inside the RZ. The second shows the accumulation of particles on the wall. These results highlight zones prone to wind erosion and particle deposition around the hills. Last but not least, the fluxes of particle trapping and deposition inside the RZ are quantified and compared to the incoming flux from upstream. These fluxes, albeit relatively weak in comparison to the incoming one, contribute potentially to dune migrations and desertification.