Orientador: Ulisses Rocha Antuniassi / Banca: Otavio Jorge Gricoli Abi Saab / Banca: Marco Antonio Gandolfo / Banca: Carlos Gilberto Raetano / Banca: Paulo Roberto Arbex Silva / Resumo: A alta demanda por agrotóxicos pelos sistemas de produção agrícola, aliada ao possível uso inadequado desses produtos, torna a deriva um dos maiores problemas potenciais da agricultura atual, e a escolha correta de adjuvantes pode ser uma das alternativas para minimizar os impactos negativos causados pela deriva nas pulverizações. Este trabalho foi desenvolvido com o objetivo de avaliar o efeito proporcionado por diferentes grupos de adjuvantes nas propriedades físicas e químicas das soluções, no espectro de gotas, bem como no potencial do risco de deriva quantificado em túnel de vento, como forma de auxiliar na escolha correta desses produtos para melhor utilização nas aplicações de agrotóxicos. Foram selecionados 18 adjuvantes comumente utilizados em misturas com agrotóxicos em pulverizações agrícolas, avaliando-se as propriedades físicas e químicas dos mesmos em soluções aquosas (viscosidade, densidade, tensão superficial e condutividade elétrica), o espectro de gotas e o potencial de deriva medido em túnel de vento. O experimento foi composto de 33 tratamentos, tendo a água como testemunha adicional, resultantes da diluição dos adjuvantes em diferentes concentrações, com três repetições. Para os ensaios em túnel de vento e análise de espectro de gotas foi utilizada uma ponta de pulverização XR8003 VK na pressão de 200 kPa, gerando um padrão de gotas médias. A deriva foi coletada no túnel de vento com fluxo de ar na velocidade de 2 m s-1. O corante Azul Brilhante a 0,6% (m v-1) foi utilizado como marcador para todas as soluções pulverizadas visando a quantificação da deriva por espectrofotometria. Os resultados mostraram que a adição de adjuvantes alterou as propriedades físicas e químicas das soluções aquosas em diferentes magnitudes, dependendo da concentração utilizada. Os surfatantes organosilicones... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to the high demand for pesticide by the agricultural systems and the possible inadequate use of the products, drift became one of the biggest concerns of the modern agriculture, and the correct use of adjuvants may be one of the possible alternatives to minimize the negative impact of spray operations. This study was developed to evaluate the effect of different adjuvants on physical and chemical properties of spray solutions, droplets spectra as well as drift potential measured in wind tunnel, aiming the correct choice of adjuvants to improve efficiency in pesticide application. For this purpose 18 commercially available agricultural spray adjuvants were selected including products usually mixed up with pesticides in the sprayer tank. The evaluation included physical and chemical properties of spray solutions (viscosity, density, surface tension and electric conductivity), droplets spectra and drift risk potential measured in wind tunnel. The experiment was set up with 33 treatments (solutions) obtained from 18 adjuvants used in different concentrations with 3 replications, including pure water as a standard. For wind tunnel tests and droplet spectra analysis it was used a Teejet XR8003 flat fan nozzles at 200 kPa (medium droplets) and all solutions were mixed up with a food color dye (Blue FDC) at 0,6% m v-1 for spectrophotometry analysis of drift deposits on the wind tunnel. The results showed that the addition of adjuvants changed physical and chemical properties of spray solutions in different magnitudes according to the product concentration. The organosilicon surfactants (Silwet 0.1% e 0.2% and BreakThru 0,1%) had the lowest values for surface tension, while the drift retardant based polymers (Define 0,06% e 0,12%) had the highest values for viscosity and density. There was high correlation between the Volume Median Diameter (VMD) and percentage of droplets smaller... (Completo abstract click electronic access below) / Doutor

Este trabalho tem por objetivo formular um procedimento para a quantificação da vazão do ar promovida pela ação do vento no interior do edifício, em climas quentes. O procedimento é dividido em cinco partes: obtenção dos dados de vento, transposição dos dados de vento da estação meteorológica para a área de interesse, determinação dos coeficientes de pressão no edifício, determinação dos coeficientes de descarga das aberturas, e o cálculo da vazão no interior do edifício. Diversas ferramentas são apresentadas para a execução de cada etapa, e seu uso e parâmetros de entrada são discutidos. O uso de túnel de vento e a simulação com ferramentas de dinâmica dos fluidos computacional são apresentados em detalhes. O trabalho conclui que estão disponíveis aos projetistas um amplo conjunto de ferramentas para a predição da ventilação natural no interior do edifício, e que somente pelo seu uso criterioso, as conclusões são passiveis de uso no projeto arquitetônico. / The aim of this dissertation is to produce a procedure for wind-driven natural ventilation prediction, in hot climate building. The procedure is organized in five parts: wind data obtaining, topographic e roughness correction, pressure coefficient determination, discharge coefficient determination, and flow rate calculation inside the building. The dissertation presents some tools to execute each part of the procedure, and the specificities of those tools are discussed. Wind tunnel experiment and computation fluid dynamic simulation are presented in detail. The research conclusion is that designers have many tools avaliable to performe a natural ventilation prediction, but just concient use will produce reliable results for architectural design.

Much of the aerosol research completed at the University of South Florida has revolved around evaluating industrial hygiene equipment and instrumentation in environmental chambers. Data collected during these studies has provided valuable baseline data on equipment and instrument performance under calm air conditions. A newly constructed wind tunnel now allows researchers to evaluate industrial hygiene instruments under moving air conditions. Because the wind tunnel is capable of producing wind velocities that a worker could encounter in the occupational setting, researchers may gain insight into instrument performance under simulated field conditions. Because aerosols can be introduced into the new wind tunnel testing section, researchers can also challenge industrial hygiene equipment and instrumentation with aerosols in sizes ranges that are of interest in public health. The purpose of this dissertation research was to develop a new wind tunnel to be used for aerosol research at the University of South Florida. Three specific aims had to be met for this study to be successful. They included: (1) designing a wind tunnel based on best practice information outlined in scientific literature, (2) constructing an operable wind tunnel to be used for aerosol research, and (3) characterizing wind tunnel performance by examining the wind tunnel velocity profile, turbulence intensity, and aerosol introduction/collection. The actual wind tunnel was constructed to a length of approximately 20 feet, a height of approximately 2 feet at its tallest point, and includes an entrance filter housing, a settling chamber, a contraction, a testing section, a diffuser, an exit filter housing, a fan, and exhaust duct. All components were designed and constructed using guidelines and best practices reported in the scientific literature. Velocity profile measurements were the first way that this wind tunnel was characterized. In order to successfully obtain measurements, the wind tunnel cross section was divided into 16 equal quadrants. Five measurements were taken for each quadrant at each wind velocity. Target wind velocities for this research were 0.5 m/s, 1.0 m/s, and 2.0 m/s. Actual average wind velocities of 0.48 m/s, 1.00 m/s, and 2.04 m/s. All were within established limits reported in the scientific literature. Turbulence intensity measurements were the second way that this wind tunnel was characterized. In order to successfully obtain measurements, the wind tunnel cross section was divided into 16 equal quadrants. Five measurements were taken for each quadrant at each wind velocity. Wind tunnels are typically designed to have the lowest turbulence intensity possible, generally below 10%. The overall average turbulence intensities for this wind tunnel at wind velocities of 0.5 m/s, 1.0 m/s, and 2.0 m/s were 9%, 10%, and 8% respectively. Overall turbulence intensity measurements were at or below 10%. Isokinetic sampling was the final method used to characterize this wind tunnel by collecting and detecting aerosols traveling through the wind tunnel testing section. The wind tunnel was operated at wind velocities of 0.5 m/s, 1.0 m/s, and 2.0 m/s with isokinetic sampling flow rates of 15.4 L/min, 30.9 L/min, and 61.7 L/min respectively. Monodisperse fluorescent polystyrene latex spheres were used as the test aerosol because they are uniform in size and shape and can be detected by fluorometry. The Blaustein Multi-Jet Atomizer (BLAM) was used to generate monodisperse fluorescent polystyrene latex aerosol 0.5 µm and 2.0 µm particles from liquid suspensions. The Vilnius Aerosol Generator (VAG) was used to generate monodisperse fluorescent polystyrene latex aerosol of 6.0 µm and 12.0 µm particles from dry powders. Nitrogen gas was used for delivering test aerosols into the wind tunnel. Five experimental runs were completed for each particle size and wind velocity for a total of 60 experimental runs. Fluorescence was detected in all 60 samples with average mass concentrations ranging from 0.000050 ng/ml to 0.002703 ng/ml. Based on velocity profile measurements, turbulence intensity measurements, and isokinetic sampling, the performance of University of South Florida wind tunnel was found to be excellent, indicating that it was designed and constructed appropriately. The wind tunnel can now successfully be used by researchers interested in evaluating industrial hygiene sampling equipment with aerosols ranging from 0.5 µm to 12.0 µm in moving air with velocities ranging from 0.5 m/s to 2.0 m/s.

Sufficient heat dissipation is crucial to the effective operation of friction based braking systems. Such cooling is generally provided by ensuring a sufficient supply of cooling air to the heated components, hence the aerodynamics in the region of the brake components is extremely important. The objective of the research was to develop an understanding of how aerodynamics could be used to improve the cooling of automotive disc brakes. Two separate sets of wind tunnel experiments were developed. Tests were performed on a vented disc (rotor) to measure the internal flow through the vents on a rotating vented disc under various conditions, including an isolated disc in still air, the disc in still air with the wheel on, the disc in moving air with the wheel on, and an on-road simulation using a ¼ car. On vehicle tests were also performed in a wind tunnel using a purpose built brake test rig. These tests measured the thermal performance of different brake discs under various operating parameters; including constant load braking, and cooling from high temperature under various speeds, wheels and disc types. It was found that airflow through vented rotors was significantly reduced during simulated on-road driving, compared to when measured in isolation, but not particularly affected by the vehicles speed. In the situations tested, vented discs offered a 40+% improvement in cooling over an equivalent sized solid rotors. However the research indicates that the greatest benefit of vented rotors over solid will be in vehicles where air entering the wheel cavity is limited, such as low drag vehicles. It was also found that the most significant improvements in brake thermal performance could be achieved by maximising the airflow into the region of the brake components; including increasing the open area of the wheel, and increasing the vehicle velocity. Other improvements can be achieved by using a wheel material with good conductive capability, and increasing the mass of the disc. Evidence of vortex shedding was also discovered in the airflow at the exit of an internal vented rotor, any reduction in this flow disturbance should lead to increased airflow with associated improvements in thermal performance.

Methods for structural design, control, and testing offlexible aircraft structures are considered. Focus is onnonconventional aircraft con- figurations and control concepts.The interaction between analysis and testing is a central topicand all studies include validation testing and comparisonbetween computational and experimental results. The first part of the thesis is concerned with the designand testing of an aeroelastic wind-tunnel model representing aBlended Wing Body (BWB) aircraft. The investigations show thata somewhat simplified wind-tunnel model design concept isuseful and efficient for the type of investigations considered.Also, the studies indicate that well established numericaltools are capable of predicting the aeroelastic behavior of theBWB aircraft with reasonable accuracy. Accurate prediction ofthe control surface aerodynamics is however found to bedifficult. A new aerodynamic boundary element method for aeroelastictimedomain simulations and its experimental validation arepresented. The properties of the method are compared totraditional methods as well as to experimental results. Thestudy indicates that the method is capable of efficient andaccurate aeroelastic simulations. Next, a method for tailoring a structure with respect to itsaeroelastic behavior is presented. The method is based onnumerical optimization techniques and developed for efficientdesign of aeroelastic wind-tunnel models with prescribed staticand dynamic aeroelastic properties. Experimental validationshows that the design method is useful in practice and that itprovides a more efficient handling of the dynamic aeroelasticproperties compared to previous methods. Finally, the use of multiple control surfaces andaeroelastic effects for efficient roll maneuvering isconsidered. The idea is to design a controller that takesadvantage of the elasticity of the structure for performancebenefits. By use of optimization methods in combination with afairly simple control system, good maneuvering performance isobtained with minimal control effort. Validation testing usinga flexible wind-tunnel model and a real-time control systemshows that the control strategy is successful in practice.Keywords: aeroelasticity, active aeroelastic structures,aeroelastic tailoring, control, structural optimization,wind-tunnel testing. / QC 20120320

This dissertation investigates characteristics of the vertical distributions of mass flux observed in field and laboratory experiments. Thirty vertical mass flux profiles were measured during a field experiment in Jericoacoara, Brazil from October to November, 2008. These data were supplemented with 621 profiles gathered from an extensive review of the aeolian literature. From the field experiment, the analysis of the grain-size statistics for the flux caught in each trap shows that a reverse in grain-size trends occurs at an inflection zone located 0.05 ? 0.15 m above the bed. Below this inflection, mean grain-size decreases steeply with elevation in the near bed region dominated by reptation and saltation modes of transport. Above the inflection there is a coarsening of grain size with elevation; as saltation becomes the dominant transport mode. These results indicate that the coarsest grains are found close to and farthest from the bed. Using a data set comprising 274 vertical flux profiles, the performance of the exponential, power and logarithmic functions were tested to see which provided the best fit to the vertical flux distributions. The exponential function performed best 88% of the time. The average r2 value for the grouped exponential, logarithmic, and power function fits are 0.98, 0.85 and 0.91, respectively. The populations of the exponent coefficients, representing the relative rate of decrease with height above the surface, or slope of the vertical mass flux profiles, are statistically different in wind tunnels and field experiments. The slopes of the vertical flux profiles observed in wind tunnel experiments are steeper compared to field environments, which infers that saltation is suppressed in wind tunnels. These differences are magnified in wind tunnels with small working cross section areas, and in wind tunnel experiments that use extreme environmental conditions, such as very high shear velocities. The Rouse concentration model, widely used in water studies, was tested to see if it could replicate the observed vertical flux distributions and transport rates. A fall velocity (w0) equation for particles falling in air was derived using a grain size (d) dependency: w0 (in m/s) = 4.23d (in mm) + 0.1956 (r^2=0.88). The Rouse model performs poorly when the value of the beta (a form of the Schmidt number in the Rouse number exponent) is assumed to be unity. The values of beta were modeled using a relationship derived from a dependency of beta on the w0/u* ratio: beta = 3.2778(w0/u*) - 0.4133 (r^2=0.65). The values of beta ranged from 6.11 ? 17.83 for all the experiments. The Rouse profiles calculated using this approach predict very similar vertical distributions to the observed data and predicted 86% and 81% of the observed transport rate in field and wind tunnel experiments respectively. The Rouse approach is more physically meaningful than current approaches that use standard curve fitting functions to represent the vertical flux data but do not provide any explanatory power for the shape or magnitude of the profile.

A renovation of an adaptive-wall wind tunnel was completed to improve flow quality, automate data acquisition, integrate a three-axis traversing mechanism, and regain functionality of an adaptive-wall test section. Redesign of the settling chamber significantly improved flow quality, with the resulting turbulence intensity of 0.3% and flow uniformity of ±0.6% matching characteristics of research-grade wind tunnels. The functionality of the adaptive-wall test section was tested by analyzing the effect of wall adaptation on flow development over a circular cylinder. Experiments were carried out for a Reynolds number (Red) of 57,000 for three blockage ratios: 5%, 8%, and 17%. Measurements were made in three wall configurations: geometrically straight walls (GSW), aerodynamically straight walls (ASW), and streamlined walls (SLW). Solid blockage effects were clearly evident in cylinder surface pressure distributions for the GSW and ASW configurations, manifested by an increased peak suction and base suction. Upon streamlining the walls, pressure distributions for each blockage ratio matched distributions expected for low blockage ratios. Wake blockage limited wake growth in the GSW configuration at 7.75 and 15 diameters downstream of the cylinder for blockages of 17% and 8%, respectively. This adverse effect was rectified by streamlining the walls with the resulting wake width development matching that expected for low blockage ratios. Wake vortex shedding frequency and shear layer instability frequency increased in the GSW and ASW configurations with increasing blockage ratio. Invariance of the near wake width with wall configuration suggests that frequency increase is caused by the increased velocity due to solid blockage effects. For all the blockage ratios investigated, the increased wake vortex shedding frequency observed in the ASW and GSW configurations was corrected in the SLW configuration, with the resulting Strouhal numbers of about 0.19, matching that expected for low blockage ratios at the investigated Red.

The goal of this thesis work has been to develop and manufacture an ice layer which was to be mounted on the tip of a scaled down wing model. The iced wing should be tested in a wind tunnel and aerodynamic comparisons should be made to the same wing without ice.The development of the ice was carried out as a modified product development process. The main differences are that there is no costumer and that the actual shape and functions of the product are more or less predetermined. The challenge was to find the best way to create the ice layer and how to mount it to the wing without damaging it or covering any pressure sensors. Product development methods such as pros and cons lists and prototypes were used to solve problems before printing the plastic ice layer in a rapid prototyping machine.Wind tunnel experiments were then conducted on the wing with and without the manufactured ice. Raw data from the wind tunnel were processed and lift and drag coefficients were calculated using mathematical equations. Finally, conclusions were drawn by comparing the results from the wind tunnel tests with theory, other works as well as CFD simulations.The ice layer was successfully manufactured and it met the target specifications. The aerodynamic performance of an iced aircraft wing proved to be considerably worse compared to a blank wing. The maximum achievable lift force decreased by 22% and an increased drag force will require more thrust from the airplane.

A renovation of an adaptive-wall wind tunnel was completed to improve flow quality, automate data acquisition, integrate a three-axis traversing mechanism, and regain functionality of an adaptive-wall test section. Redesign of the settling chamber significantly improved flow quality, with the resulting turbulence intensity of 0.3% and flow uniformity of ±0.6% matching characteristics of research-grade wind tunnels. The functionality of the adaptive-wall test section was tested by analyzing the effect of wall adaptation on flow development over a circular cylinder. Experiments were carried out for a Reynolds number (Red) of 57,000 for three blockage ratios: 5%, 8%, and 17%. Measurements were made in three wall configurations: geometrically straight walls (GSW), aerodynamically straight walls (ASW), and streamlined walls (SLW). Solid blockage effects were clearly evident in cylinder surface pressure distributions for the GSW and ASW configurations, manifested by an increased peak suction and base suction. Upon streamlining the walls, pressure distributions for each blockage ratio matched distributions expected for low blockage ratios. Wake blockage limited wake growth in the GSW configuration at 7.75 and 15 diameters downstream of the cylinder for blockages of 17% and 8%, respectively. This adverse effect was rectified by streamlining the walls with the resulting wake width development matching that expected for low blockage ratios. Wake vortex shedding frequency and shear layer instability frequency increased in the GSW and ASW configurations with increasing blockage ratio. Invariance of the near wake width with wall configuration suggests that frequency increase is caused by the increased velocity due to solid blockage effects. For all the blockage ratios investigated, the increased wake vortex shedding frequency observed in the ASW and GSW configurations was corrected in the SLW configuration, with the resulting Strouhal numbers of about 0.19, matching that expected for low blockage ratios at the investigated Red.

<p>Theoretical and experimental studies are conducted in the field of aeroelasticity. Specifically, two rectangular and one cropped delta wings with a hole are analyzed in this dissertation for their aeroelastic behavior.</p><p>The plate-like wings are modeled using the finite element method for the structural theory. Each wing is assumed to behave as a linearly elastic and isotropic, thin plate. These assumptions are those of small-deflection theory of bending which states that the plane sections initially normal to the midsurface remain plane and normal to that surface after bending. The wings are modeled in low speed flows according to potential flow theory. The potential flow is governed by the aerodynamic potential equation, a linear partial differential equation. The aerodynamic potential equation is solved using a distribution of doublets that relates pressure to downwash in the doublet lattice method. A hole in a wing-like structure is independently investigated theoretically and experimentally for its structural and aerodynamic behavior.</p><p>The aeroelastic model couples the structural and aerodynamic models using Lagrange's equations. The flutter boundary is predicted using the V-g method. Linear theoretical models are capable of predicting the critical flutter velocity and frequency as verified by wind tunnel tests. Along with flutter prediction, a brief survey on gust response and the addition of stores(missile or fuel tanks) are examined.</p> / Dissertation