With the ever more stringent requirements of emissions and fuel economy imposed on the automotive industry, there is a need to understand more fully all aspects of the internal combustion engine to meet these requirements and at the same time the desire of the customer for acceptable performance. This research was aimed at investigating one part of the engine behaviour i.e. induction of the fresh charge to the engine cylinder. Conventionally, these measurements have been performed on a steady state flow rig, where bulk, integral measurements for mass flow rate and swirl or tumble ratio are performed. However, for some of the combustion strategies now being implemented on modern engines, the flow structure is becoming more important necessitating the use of techniques that can measure the flow field and its interaction with spray systems. This piece of work compares engine flow measurements on both a standard steady flow rig and in the cylinder of a motored engine. The flow bench measurements are both easier and cheaper to implement, but serve no real purpose unless there is a correspondence between the flow measured under steady state conditions and that measured in the transient environment of an engine cylinder. On the steady flow bench, both conventional measurements and also measurements of the detailed flow using laser Doppler anemometry have been made. This allowed a direct comparison to be performed between these two sets of measurements. Laser Doppler anemometry measurements were than performed in the cylinder of a motored engine, allowing a direct comparison between the results from the steady flow rig and the engine. Additionally, particle image velocimetry was used to investigate the data on the steady flow bench. It was found that the laser Doppler anemometry measurements were no substitute in terms of accuracy, when compared to the integral measurement of mass flow rate. They did however give some insight into the flow patterns being generated within the cylinder under these conditions. When compared to similar measurements in the engine, in most instances a high degree of correlation was found between the air velocity measurements, although the tumble ratio calculated from the engine was generally higher than that from the steady flow bench. A comparison of vector flows fields from the particle image velocimetry for the steady state and laser Doppler anemometry for the engine measurements, suggested that the influence of the piston on the flows, not present for steady state measurements, was only relevant in the neighbourhood of the piston itself. The transient nature of the flow in engine also seemed to show very little differences between the two sets of measurements. It was concluded that ideally both sets of measurements are required, but that a lot of the detail, with some additional work, could be extracted from the steady flow measurements, but only by using laser diagnostics to measure the flow fields. It was also observed that more than one plane of measurements is required using laser diagnostics to fully characterise the tumble flow field, which is not uniform across the cylinder. This also led to a simple form of weighting of the data in different planes which could be improved with a more detailed set of measurements to gain better insight into the weighting factors required.

In this thesis, three fluid dynamical problems are studied. First in chapter 2 we investigate, via both theoretical and experimental methods, the swimming motion of a magnetotactic bacterium having the shape of a prolate spheroid in a viscous liquid under the influence of an imposed magnetic field. The emphasis of the study is placed on how the shape of the non-spherical magnetotactic bacterium, marked by the size of its eccentricity, affects the pattern of its swimming motion. It is revealed that the pattern/speed of a swimming spheroidal magnetotactic bacterium is highly sensitive not only to the direction of its magnetic moment but also to its shape. Secondly, an important unanswered mathematical question in the theory of rotating fluids has been the completeness of the inviscid eigenfunctions which are usually referred to as inertial waves or inertial modes. In chapter 3 we provide for the first time a mathematical proof for the completeness of the inertial modes in a rotating annular channel by establishing the completeness relation, or Parseval’s equality, for any piecewise continuous, differentiable velocity of an incompressible fluid. Thirdly, in chapter 4 we investigate, through both asymptotic analysis and direct numerical simulation, precessionally driven flow of a homogeneous fluid confined in a fluid-filled circular cylinder that rotates rapidly about its symmetry axis and precesses about a different axis that is fixed in space. A particular emphasis is placed on the spherical-like cylinder whose diameter is nearly the same as its length. An asymptotic analytical solution in closed form is derived in the mantle frame of reference for describing weakly precessing flow in the spherical-like cylinder at asymptotically small Ekman numbers. We also construct a three-dimensional finite element model, which is checked against the asymptotic solution, in attempting to elucidate the structure of the nonlinear flow.

Reliability of a piston rod position measurement system is key when applied to large hydraulic cylinders. This and other requirements lead to the development of the CIMS (Cylinder Integrated Measurement System), a contactless and highly accurate system that uses the Hall effect to detect an encoded piston rod. To eliminate deviations caused by mechanical tolerances, temperature and air gap variations etc., the raw signals are filtered and compensated. Its functionality has been extended by making statistical data available, based on the values measured. These include the number of strokes, cumulative stroke length, stroke length distribution, maximum velocity and acceleration, temperature classification and extreme temperatures. Assessment of these data enables the user to optimize his application. Comparison to historic data can give input to the preventive maintenance plan to reduce (unforeseeable) system downtime and to increase the system reliability. This development resulted into the CIMSmart. It is a significant step towards cylinder intelligence.

This report describes the development of a software for computing viscous incompressiblemultiphase ows. The software does this with solving the coupled non-linear Navier-Stokes(Fluid) and the Cahn-Hilliard (Phase-Field) equations using a Finite Element Method. Thereason for the development is to produce a simulation tool, which eventually is capable ofsimulating the ow of uids inside the OptusAir aeronator manufactured by the Sorubincompany. The solving software developed is built on the ParMetis, PETSc and OpenMPIframeworks. Our primary benchmark has been a geometry resembling the OptusAir product,a cylinder with a rotating bottom. We have made comparisons between simulation resultsand the theory of a free surface in a uniform rotating ow.This thesis shows that the shape of the interface between two uids coincides with theoryto some extent, while the approximate boundary conditions prevent it from coinciding fully.

Steel silos are widely used as long-term or short-term containers for the storage of granular solids, of which a huge range are stored, from flour to iron ore pellets, coals, cement, crushed rocks, plastic pellets, chemical materials, sand, and concrete aggregates. The radius to thickness ratio for silos is in the range of 200 to 3000, so they fall into the category of thin shells, for which failure by buckling is the main concern and requires special attention in design. The primary aim of this thesis is to investigate the possible application of Fibre Reinforced Polymer (FRP) as a new repair and strengthening technique to increase the buckling capacity of thin metallic cylindrical shells. Extensive research has been conducted on the use of fibre reinforced polymer (FRP) composites to strengthen concrete, masonry and timber structures as well as metallic beams. However, all these studies were concerned with failure of the structure by material breakdown, rather than stability. As a result, this thesis marks a major departure in the potential exploitation of FRP in civil engineering structures. Many analyses of cylindrical shells are presented in the thesis. These are all focussed on strengthening the shell against different failure modes. Two loading conditions were explored: uniform internal pressure accompanied by axial load near a base boundary, and axial loads with geometric imperfections. For the latter, local imperfections are usually critical, and two categories of imperfection were studied in detail: an inward axisymmetric imperfection and a local dent imperfection. For the first loading condition, which leads to elephant’s foot buckling, an analytical method was used to derive general equations governing the linear elastic behaviour of a cylindrical shell that has been strengthened with FRP subject to internal pressure and axial compression. It was used to identify optimal application of the FRP. All the later studies were conducted using nonlinear finite element analysis (using the ABAQUS program) to obtain extensive predictions of many conditions causing shell buckling and the strengthening effect of well-placed FRP. In all the cases studied in this thesis, it was shown that a small quantity of FRP composite, applied within a small zone, can provide a significant enhancement of the resistance to buckling failure of a thin metal cylinder. These calculations demonstrate that this new technique is of considerable practical value. However, it is clear that not all the relevant questions have been fully answered, so the author poses appropriate questions and makes suggestions for future work.

The degree project has been carried out in collaboration with Husqvarna, a world-leading manufacturer of products for gardening, park and forest management. An ever-evolving industry where innovation and creativity are required to be at the top. With constant demands from customers on performance and quality, a constant mechanical and design developments are required. Husqvarna's chainsaws use two-stroke engines where the scavenging channel are covered by a lid which in turn is fastened with screw joints. The channel through which the fuel mixture is pumped is open and a lid is needed to seal the channel. The channel is closed by screw joints, which in turn has a cost related to articles and materials. The lid that is fastened with screw joints has, one step in the production, articles concerning screws and fastening functions in the cylinder. The screw towers located on the cylinder could be an opportunity for improvement regarding weight in order to optimize the product. The aim of investigating new fastening methods is to see what possible improvements are available compared to the current method. These include weight reduction, which is very significant for these products. With a thorough literature study on attachment methods, a Pugh-matrix with its own values ​​has been utilized. It has helped to see which concepts are best suited within the weighting framework. The theories are built from scientific manuals within mechanics, strength and joints. With this basis, conclusions have been made regarding the functions that have been investigated and whether they are positive or negative in relation to the current method. The work is meant as a basic basis for Husqvarna, which can facilitate the use of alternative fastening methods for the channel cover.

This study was composed on behalf of Husqvarna Group AB and is the thesis for the writers’ bachelor's degree, majoring in Mechanical Engineering Product Development and Design. Husqvarna Group is one of the leading manufacturers in the world within forest, park and garden care products, such as chainsaws, lawn movers and trimmers. To retain future-safe and sustainable products it is constantly required to develop them in terms of power efficiency and ergonomics. In a gasoline-powered chainsaw, the cylinder is one of the most critical components within the motor set where its complexity and operational function is vital for the motor’s overall performance. The cylinder’s main tasks, which are to create a cylinder bore for the piston and a combustion chamber, cause the need for decisive properties in the cylinder’s construction and design, such as heat transfer and heat control. In order to enable an increase of the power in the engine, these properties are required to be considered and improved. With a defective cooling, various types of damages can occur in the engine, but also counteract the desired increase in engine power. The aim of this study is to develop a concept of a cylinder with improved characteristics for heat control. By support from accepted theories and former studies, method choices are carried out to generate concepts and analyze results. In order to give rise to the pros and cons concerning the final concept and its constituent subparts, the generating of the concepts and analyzing of its results has been taken place in parallel to one another.  The result of the work is a detached cylinder head, where the focus has been to produce proposals for the cylinder’s selection of seal, material and screw joints. When proposals in these areas were analyzed and selected, a simulation was made to examine whether the heat distribution in the cylinder had changed. The cylinder presented as the final concept is made of an aluminum alloy with a gasket of a mica material to keep the cleavage sealed. With the new conditions for fastening, a proposed design and material selection for screw joints are presented.   This study has taken the approach in a work that requires more time and resources and can inspire a resumption of the case. / Den här studien gjordes på uppdrag av Husqvarna Group AB och är ett examensarbete för skribenternas ingenjörsutbildning inom maskinteknik, produktutveckling och design.   Husqvarna Group är en av de världsledande tillverkarna för produkter inom skogs-, park-, och trädgårdsskötsel, såsom motorsågar, gräsklippare och trimmers. För framtidssäkra och hållbara produkter krävs det att ständigt utveckla dessa i mån av effektivitet och ergonomi. I en bensindriven motorsåg är cylindern en mycket viktig komponent där dess komplexitet och funktion är vital för motorsågens slutgiltiga funktionalitet. Cylinderns huvudsakliga uppgifter, vilka är att skapa ett cylinderlopp för kolven samt en förbränningskammare, förorsakar behov för avgörande egenskaper i cylinderns konstruktion och design, egenskaper såsom värmeöverföring och värmekontroll. Med en bristfällig kylning kan bland annat olika typer av skador förekomma i motorn, men också motverka den eftersträvande ökningen av motorns effekt. Arbetets syfte är att ta fram ett koncept på en cylinder med förbättrade egenskaper för en ökad kontroll av värmeutvecklingen. Genom underlag från vedertagna teorier inom produktutveckling samt inspiration från tidigare studier, genomförs metodval för att generera koncept och analysera resultat. För att ge upphov till för- och nackdelar beträffande slutkonceptets ingående områden, har konceptgenerering och analysering skett parallellt.   Resultatet av studien redovisar en delad cylindertopp, där arbetets fokus har varit att ta fram förslag på cylinderns tätning, material och skruvförband. När förslag inom dessa områden hade analyserats och valts, gjordes en simulering för att granska huruvida värmefördelningen i cylindern hade förändrats. Den cylinder som presenteras som det slutgiltiga konceptet är tillverkad av en aluminiumlegering med en packning av ett glimmermaterial för att hålla delningen tät. I och med de nya förutsättningarna på infästning presenteras också ett förslag på skruvförband med tillämpad utformning och materialval.   Studien har tagit ansats i ett arbete som kräver mer tid och resurser och kan vara till inspiration vid ett återupptagande av ärendet.

Neste trabalho avaliou-se experimentalmente a influência da onfiguração de bobinagem no comportamento mecânico de cilindros de compósito polimérico com bobinagem simétrica e assimétrica. Para tanto, foram fabricados pelo processo de bobinamento filamentar (filament winding) dois grupos de cilindros com extremidades abertas, que apresentaram alteração no posicionamento das camadas em relação ao plano médio, caracterizando laminados simétrico e assimétrico. No compósito deste estudo, utilizou-se uma matriz com sistema tricomponente com resina epoxídica e reforço de fibra de carbono. Para avaliação da resistência mecânica, os cilindros foram submetidos a ensaio hidrostático que consistiu da pressurização interna em dispositivo apropriado mediante a utilização de um fluido até que ocorresse o colapso. Adicionalmente, as deformações e os modos de falha dos dois grupos de cilindros foram analisados e comparados. A utilização de um programa de cálculo de elementos finitos permitiu concluir que esta ferramenta, muito usada em projeto, não consegue identificar tensões na orientação da fibra em cada uma das camadas do compósito, bem como tensões de cisalhamento interlaminares que surgem nos cilindros com configuração assimétrica. Os resultados dos ensaios mostraram que as configurações de bobinagem exercem influência no comportamento mecânico dos cilindros de material compósito, favorecendo a construção do tipo simétrica. / This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction.

O desgaste de anéis de pistão e cilindro foi modelado através de um programa computacional que calcula as pressões hidrodinâmicas e de contato rugoso agindo nas superficies deslizantes de contato. Os valores previstos de desgaste são comparados com um ensaio em dinamometro de um motor diesel. / The wear of piston rings and cylinder liner was modelled through a computer code that calculates the hydrodynamic and roughness contact pressures acting in the contact surfaces. The predicted wear is compared with a 750 hours dynamometer test of a medium duty diesel engine

"Ultrasound has become a widely used form of medical imaging because it is low-cost, safe, and portable. However, it is heavily dependent on the skill of the operator to capture quality images and properly detect abnormalities. Training is a key component of ultrasound, but the limited availability of training courses and programs presents a significant obstacle to the wider use of ultrasound systems. The goal of this work was to design and implement an interactive training system to help train and evaluate sonographers. This Virtual Training System for Diagnostic Ultrasound is an inexpensive, software-based training system in which the trainee scans a generic scan surface with a sham transducer containing position and orientation sensors. The observed ultrasound image is generated from a pre-stored 3D image volume and is controlled interactively by the user€™s movements of the sham transducer. The patient in the virtual environment represented by the 3D image data may depict normal anatomy, exhibit a specific trauma, or present a given physical condition. The training system provides a realistic scanning experience by providing an interactive real-time display with adjustable image parameters similar to those of an actual diagnostic ultrasound system. This system has been designed to limit the amount of hardware needed to allow for low-cost and portability for the user. The system is able to utilize a PC to run the software. To represent the patient to be scanned, a specific scan surface has been produced that allows for an optical sensor to track the position of the sham transducer. The orientation of the sham transducer is tracked by using an inexpensive inertial measurement unit that relies on the use of quaternions to be integrated into the system. The lack of a physical manikin is overcome by using a visual implementation of a virtual patient in the software along with a virtual transducer that reflects the movements of the user on the scan surface. Pre-processing is performed on the selected 3D image volume to provide coordinate transformation parameters that yield a least-mean square fit from the scan surface to the scanning region of the virtual patient. This thesis presents a prototype training system accomplishing the main goals of being low-cost, portable, and accurate. The ultrasound training system can provide cost-effective and convenient training of physicians and sonographers. This system has the potential to become a powerful tool for training sonographers in recognizing a wide variety of medical conditions."