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Experimentelle Untersuchung von Strömung und Wärmeübergang in Kühlkanälen mit wirbelerzeugenden ElementenHenze, Marc, January 2007 (has links)
Stuttgart, Univ., Diss., 2007. / Druckausg. beim Hut-Verl., München erschienen.
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Numerical simulation of vortex generating jets in zero and adverse pressure gradients /Memory, Curtis Lynn, January 2007 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2007. / Includes bibliographical references (p. 69-70).
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The effects of vortex generator jet frequency, duty cycle, and phase on separation bubble dynamics /Bloxham, Matthew Jon, January 2007 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2007. / Includes bibliographical references (p. 67-69).
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Volumetric PIV and OH PLIF imaging in the far field of nonpremixed jet flamesGamba, Mirko. January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Aug. 6, 2009). Vita. Includes bibliographical references.
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The significance of coherent flow structures for the turbulent mixing in wall-bounded flows /Kähler, Christian. January 2004 (has links)
Zugl.: Göttingen, University, Diss., 2004. / Zugl.: Göttingen, Univ., Diss., 2004.
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Sichtbarmachung und Geschwindigkeitsmessung in Leeseitenwirbeln bei ÜberschallanströmungLang, Neven. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 2000--Aachen. / Gedr. Ausg. bei Books on Demand, Norderstedt.
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Untersuchungen der instationären Strömungsvorgänge in Seitenkanalverdichtern mit Hilfe der Particle Image VelocimetrySchroll, Michael. Unknown Date (has links) (PDF)
Techn. Universiẗat, Diss., 2003--Berlin.
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Particle Image Segmentation Based on Bhattacharyya DistanceJanuary 2015 (has links)
abstract: Image segmentation is of great importance and value in many applications. In computer vision, image segmentation is the tool and process of locating objects and boundaries within images. The segmentation result may provide more meaningful image data. Generally, there are two fundamental image segmentation algorithms: discontinuity and similarity. The idea behind discontinuity is locating the abrupt changes in intensity of images, as are often seen in edges or boundaries. Similarity subdivides an image into regions that fit the pre-defined criteria. The algorithm utilized in this thesis is the second category.
This study addresses the problem of particle image segmentation by measuring the similarity between a sampled region and an adjacent region, based on Bhattacharyya distance and an image feature extraction technique that uses distribution of local binary patterns and pattern contrasts. A boundary smoothing process is developed to improve the accuracy of the segmentation. The novel particle image segmentation algorithm is tested using four different cases of particle image velocimetry (PIV) images. The obtained experimental results of segmentations provide partitioning of the objects within 10 percent error rate. Ground-truth segmentation data, which are manually segmented image from each case, are used to calculate the error rate of the segmentations. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015
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Experimental investigation of oscillating-foil technologiesIverson, Dylan 01 October 2018 (has links)
This thesis contains an experimental campaign on the practical implementation of
oscillating-foil technologies. It explores two possible engineering applications of
oscillating-wings: thrust-generation, and energy-extraction. The history of, benefits of,
and difficulties involved in the use of oscillating-foils is discussed throughout. Many
existing technologies used for thrust generation and hydrokinetic energy extraction are
based on rotating blades or foils, which have evolved over decades of use. In recent
years, designs that use oscillating-foils, with motions analogous to the flapping of a
fish’s tail or a bird’s wing, have shown increased hydrodynamic performance compared
to the traditional rotary technologies. However, these systems are complex, both in
terms of the governing unsteady fluid dynamics, and the methods by which kinematics
are prescribed. Simply put, system complexity and cost need to be reduced before
these devices see wide-spread use. For this reason, the work contained within this
thesis explores possible methods of reducing the complexity of oscillating-foil systems
in an effort to contribute to their development. For thrust-generation applications, this
entailed using flexible foils to create passive pitching kinematics. This was
parametrically studied by testing foils of different structural properties under a range of
kinematics. The results suggested that properly tuning the flexibility of the foil could
enhance both the thrust generation, and the efficiency of the propulsive system. With
respect to energy-harvesting applications, the reliability of a novel fully passive turbine
was assessed. The prototype tested had no active control strategy, and the degreesof-freedom
were not mechanically linked, greatly simplifying the design. The prototype
was subjected to real-world conditions, including high turbulence levels and the wake
of an upstream turbine, and displayed robust performance in most conditions. In both
applications, the hydrodynamic performance of the oscillating-wings was directly
measured, and particle image velocimetry was used to observe the flow topology in the
wakes and boundary layers of the foils. The vortex and stall dynamics were highlighted
as key flow features, and are studied in detail. / Graduate
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Etude 3D d’un tourbillon dans un champ de houle par holographie numérique / 3D study of a vortex dynamics under water waves by digital in-line holographyLebon, Benoît 15 February 2017 (has links)
Cette thèse traite de l'application de l'holographie numérique dans l'axe à l'étude d'une dynamique tourbillonnaire dans un champ de houle. Lors du passage de la houle au dessus d'une structure immergée, des tourbillons se forment à ses extrémités. Ces tourbillons ont un impact fort sur la dynamique proche des structures et peuvent engendrer des problèmes d'affouillement ou de vieillissement prématuré. On s'intéresse donc à la dynamique tridimensionnelle de ces tourbillons qui sont rapidement l'objet de déformations menant à leur éclatement. Pour étudier ce mécanisme, le problème est modélisé par une géométrie simple, une plaque soumise à une houle monochromatique. Les expériences sont menées dans un canal à houle de 10 m de long et 30 cm de large. Pour mesurer la dynamique 3D on utilise une technique innovante, l'holographie numérique qui permet une mesure 3D3C au moyen d'une diode laser et d'une seule caméra. Ses principales limitations résident dans la dimension de la section du volume de mesure, qui est de l'ordre de la surface du capteur CCD, ainsi que du nombre de particules présentes dans le champ. Toutefois, l'holographie permet une résolution de l'ordre de la taille d'un pixel dans le plan du capteur CCD et de 3 à 5 fois le diamètre de la particule suivie dans la direction orthogonale au capteur. Ces mesures permettent de suivre individuellement plusieurs centaines de particules dans le champ et d'en mesurer les vitesses. Enfin des mesures complémentaires en stéréo-piv confirment les résultats obtenues par holographie et permettent l'étude du confinement du tourbillon sous l'action combinée de la surface libre et de la plaque. / This thesis deals with the use of digital in-line holography to the study of a vortex dynamics under water waves. As waves propagate above an immersed structure, vortices are formed at its edges. Those vortices have a strong impact on the flow dynamics in the vicinity of structures and can cause scouring or damages. Thus we are interested in the three-dimensional dynamics of those vortices which are quickly distorted, leading to their breakup. To study this dynamics, the physical problem is modelled by a basic geometry, a thin plate is set under monochromatic waves. Experiments are conduct within a wave flume of dimensions 10 m long and 30 cm width. To measure the 3D flow the use of an innovative technique, the digital holography which allow a 3D3C measure with only one camera and a laser diode. Its main limitations are the size of the cross-section of the sample volume and the number of particles allowed in it. However, digital holography can localize particles with a pixel sized resolution within the plans parallel to the CCD sensor and a depth resolution in the order of 3 to 5 times the particles diameter. Those measurements enable to follow the path of each particle inside the sample volume. Finally, acquisition by stereo particle image velocimetry confirms the velocities measured by holography and are used to study the interaction between the vortex and the combined action of free surface and the plate.
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