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Auswahl der wissenschaftlichen Literatur zum Thema „Oscillating movement“
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Zeitschriftenartikel zum Thema "Oscillating movement"
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He, Zhang-Ming, Deng-Long Wang, Yan-Chao She, Jian-Wen Ding und Xiao-Hong Yan. „Nonperiodic Oscillation of Bright Solitons in Condensates with a Periodically Oscillating Harmonic Potential 10.5560/ZNA.2012-0085“. Zeitschrift für Naturforschung A 67, Nr. 12 (01.12.2012): 723–28. http://dx.doi.org/10.5560/zna.2012-0085.
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Considering a periodically oscillating harmonic potential, we explored the dynamic properties of bright solitons in a Bose-Einstein condensate by using Darboux transformation. It is found that the soliton movement exhibits a nonperiodic oscillation under a slow oscillating potential, while it is hardly affected under a fast oscillating potential. Furthermore, the head-on and/or ‘chase’ collisions of two solitons have been obtained, which could be controlled by the oscillation frequency of the potential.
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Gutnik, B. J., und B. Hyland. „Lateralized Spatial Strategies in Oscillating Drawing Movements“. Perceptual and Motor Skills 84, Nr. 2 (April 1997): 435–51. http://dx.doi.org/10.2466/pms.1997.84.2.435.
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Kinematic characteristics and lateral differences between two upper extremities were investigated in a unimanual graphic task involving fast and precise oscillating movements on the vertical plane. The spatial locations of sequential reversal points were used to calculate the pairs of angles, relative to the horizontal axis. The point biserial coefficient of correlation was used to analyze the difference between big and large angles and their sequence in each pair. Three main groups (A, B, and C) of performance models were distinguished in 132 tests by 33 strongly right-handed male subjects. Group A showed strong variation in vertical movement, Group B covariation in vertical and horizontal vectors, while Group C reflected independent variation of both vertical and horizontal directions. It is suggested that the movement strategies might reflect three different models of motor control involving coupling of an oscillator controlling pools of motoneurons which regulate horizontal movements with an oscillator controlling vertical movement (Groups A + B) or with nonoscillating control signal (Group B). It is argued that Group A represents the simplest strategy and only performance Type A met by the left hand.
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Wan, Xiaohu, Daniela Cimini, Lisa A. Cameron und E. D. Salmon. „The coupling between sister kinetochore directional instability and oscillations in centromere stretch in metaphase PtK1 cells“. Molecular Biology of the Cell 23, Nr. 6 (15.03.2012): 1035–46. http://dx.doi.org/10.1091/mbc.e11-09-0767.
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Kinetochores bound to kinetochore microtubules (kMTs) exhibit directional instability in mammalian and other mitotic vertebrate cells, oscillating between poleward (P) and away-from-the-pole (AP) movements. These oscillations are coupled to changes in length of kMTs in a way that maintains a net stretch of the centromere. To understand how sister kinetochore directional instability and kMT plus-end dynamic instability are coupled to oscillations in centromere stretch, we tracked at high resolution the positions of fluorescent kinetochores and their poles for oscillating chromosomes within spindles of metaphase PtK1 cells. We found that the kinetics of P and AP movement are nonlinear and different. By subtracting contributions from the poleward flux of kMTs, we found that maximum centromere stretch occurred when the leading kinetochore switched from depolymerization to polymerization, whereas minimum centromere stretch occurred on average 7 s after the initially trailing kinetochore switched from polymerization to depolymerization. These differences produce oscillations in centromere stretch at about twice the frequency of kinetochore directional instability and at about twice the frequency of centromere oscillations back and forth across the spindle equator.
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Kobayashi, H. „Annular Cascade Study of Low Back-Pressure Supersonic Fan Blade Flutter“. Journal of Turbomachinery 112, Nr. 4 (01.10.1990): 768–77. http://dx.doi.org/10.1115/1.2927720.
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Low back-pressure supersonic fan blade flutter in the torsional mode was examined using a controlled-oscillating annular cascade test facility. Precise data of unsteady aerodynamic forces generated by shock wave movement, due to blade oscillation, and the previously measured data of chordwise distributions of unsteady aerodynamic forces acting on an oscillating blade, were joined and, then, the nature of cascade flutter was evaluated. These unsteady aerodynamic forces were measured by direct and indirect pressure measuring methods. Our experiments covered a range of reduced frequencies based on a semichord from 0.0375 to 0.547, six interblade phase angles, and inlet flow velocities from subsonic to supersonic flow. The occurrence of unstalled cascade flutter in relation to reduced frequency, interblade phase angle, and inlet flow velocity was clarified, including the role of unsteady aerodynamic blade surface forces on flutter. Reduced frequency of the flutter boundary increased greatly when the blade suction surface flow became transonic flow. Interblade phase angles that caused flutter were in the range from 40 to 160 deg for flow fields ranging from high subsonic to supersonic. Shock wave movement due to blade oscillation generated markedly large unsteady aerodynamic forces which stimulated blade oscillation.
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Upnere, S. „Numerical Study of Flow-Induced Vibrations of Multiple Flexibly-Mounted Cylinders in Triangular Array“. Latvian Journal of Physics and Technical Sciences 55, Nr. 5 (01.10.2018): 43–53. http://dx.doi.org/10.2478/lpts-2018-0035.
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Abstract The paper presents the numerical study of vibrating multiple flexibly-mounted cylinders in a triangular rod bundle. Behavioural trends of six different clusters of oscillating rods have been analysed. The influence of neighbour cylinders on the central cylinder oscillation characteristics is analysed. Finite volume solver of open source computational fluid dynamics is used to calculate the fluid flow in the channel with the cylinder array. Built-in six degree-of-freedoms solver is utilised to simulate cylinder movement. Oscillating cylinders have two degrees-of-freedom. The obtained results are compared with numerical results available in the literature.
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Islam, Nabirul, Jochen Schanz, David Kolb und Harald Riegel. „Improvement of Surface Quality and Process Area Rate in Selective Laser Melting by Beam Oscillation Scan Technique“. Journal of Materials Engineering and Performance 30, Nr. 7 (05.05.2021): 5108–17. http://dx.doi.org/10.1007/s11665-021-05665-9.
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AbstractSelective laser melting (SLM) has potential benefits for additive manufacturing of complex and precise metal parts with required mechanical and material properties. However, the improvement of surface quality and the minimization of fabrication time still remark a challenge for efficient manufacturing by SLM. Among the process parameters, the scan strategy has a significant influence on process stability and quality of the final manufactured three-dimensional products. This paper demonstrates the investigation of an alternative scan strategy to improve the surface quality with a reduction of fabrication time and laser energy input. Hereby, the scan strategy is performed by a conventional linear and oscillating laser beam movement in a self-developed SLM process chamber. Comparative analysis of the manufactured specimens regarding surface quality and density was performed. The investigations in oscillating laser beam movement show a decrease in the average variation of surface profile up to 50% relative to the experimented conventional linear scan technique. Due to an increased melt pool during the oscillation beam movement, the hatch distance was increased. As a result, the applied laser energy input was reduced by more than 28%, and the area rate was raised up to 50% compared to the conventional linear laser beam movement.
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Lu, Liang, Shirang Long und Kangwu Zhu. „A Numerical Research on Vortex Street Flow Oscillation in the Double Flapper Nozzle Servo Valve“. Processes 7, Nr. 10 (11.10.2019): 721. http://dx.doi.org/10.3390/pr7100721.
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The oscillating flow field of the double nozzle flapper servo valve pre-stage is numerically analyzed through Large Eddy Simulation (LES) turbulent modeling with the previous grid independence verification. The vortex street flow phenomenon can be observed when the flow passes through the nozzle flapper channel, the vortex alternating in each side produces the periodical flow oscillation. The structural and flow parameter effects on the oscillating flow are emphasized, and it could be determined that the pressure on the flapper is nearly proportional to the flow velocity and inversely proportional to the actual distance between the flapper and the nozzle. On the other hand, the main frequency of oscillation decreases with the velocity and increases with the distance between the nozzle flapper. The main stage movement is further considered with a User Defined Function (UDF), and it could be determined that the influences of the structural and flow parameters on the flow oscillation are rarely changed, but the main frequencies drop, generally.
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Bulgakov, V., V. Adamchuk, І. Holovach und Ye Ihnatiev. „Mathematical model of the movement of a towed machine for cleaning beet tops residues from root crop heads“. Agricultural Science and Practice 4, Nr. 1 (15.04.2017): 3–10. http://dx.doi.org/10.15407/agrisp4.01.003.
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The work of a tractor-towed machine for cleaning beet top residues from root crop heads, when used with supporting pneumatic wheels, is accompanied with its oscillations in the vertical plane, which has consider- able impact on the quality of implementing the technological process. Therefore, the determination of opti- mal parameters for the cleaning machine, ensuring more stable movement of its cleaning working tool, in the longitudinal-vertical plane fi rst and foremost, is an important task of the mechanization of sugar beet grow- ing industry. Aim. To enhance the effi ciency of cleaning sugar beet top residues from root crop heads via the elaboration of the mathematical model of the oscillating movement of the towed machine for cleaning beet top residues from root crop heads in the longitudinal-vertical plane. Methods. The methods of building computational mathematical models for the functioning of agricultural machines and equipment, based on theoretical mechanics and advanced mathematics, were used. Results. The elaborated equivalent scheme of the movement of the towed cleaning machine was used to obtain the system of two non-linear differential equations for detailed study of the oscillations of the root crop head cleaner in the longitudinal-vertical plane while its supporting pneumatic wheels are moving along uneven soil surface. The mathematical model for the movement of the cleaner with horizontal cleaning roller, elaborated on the basis of initial dynamics equa- tions in the Lagrangian form of the second kind, allowed determining the connection between constructive and kinematic parameters of the vehicle and its oscillating characteristics. The established dependencies formed the prerequisites for further mathematical digital modelling of the parameters of the towed machine for cleaning of root crop heads with a horizontal cleaning roller. Conclusions. The established computation- al model allows optimizing the values of several parameters, characterizing the oscillations of the machine in the longitudinal-vertical plane.
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Ohorodnyk, N., K. Smolianinov und M. Ratsky. „Cellular and humoral immunity of carp at the action of biologically active additives“. Agricultural Science and Practice 4, Nr. 1 (15.04.2017): 70–73. http://dx.doi.org/10.15407/agrisp4.01.070.
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The work of a tractor-towed machine for cleaning beet top residues from root crop heads, when used with supporting pneumatic wheels, is accompanied with its oscillations in the vertical plane, which has consider- able impact on the quality of implementing the technological process. Therefore, the determination of opti- mal parameters for the cleaning machine, ensuring more stable movement of its cleaning working tool, in the longitudinal-vertical plane fi rst and foremost, is an important task of the mechanization of sugar beet grow- ing industry. Aim. To enhance the effi ciency of cleaning sugar beet top residues from root crop heads via the elaboration of the mathematical model of the oscillating movement of the towed machine for cleaning beet top residues from root crop heads in the longitudinal-vertical plane. Methods. The methods of building computational mathematical models for the functioning of agricultural machines and equipment, based on theoretical mechanics and advanced mathematics, were used. Results. The elaborated equivalent scheme of the movement of the towed cleaning machine was used to obtain the system of two non-linear differential equations for detailed study of the oscillations of the root crop head cleaner in the longitudinal-vertical plane while its supporting pneumatic wheels are moving along uneven soil surface. The mathematical model for the movement of the cleaner with horizontal cleaning roller, elaborated on the basis of initial dynamics equa- tions in the Lagrangian form of the second kind, allowed determining the connection between constructive and kinematic parameters of the vehicle and its oscillating characteristics. The established dependencies formed the prerequisites for further mathematical digital modelling of the parameters of the towed machine for cleaning of root crop heads with a horizontal cleaning roller. Conclusions. The established computation- al model allows optimizing the values of several parameters, characterizing the oscillations of the machine in the longitudinal-vertical plane.
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Gutnik, B. J., J. Nicholson, W. Go, D. Gale und D. Nash. „Are Temporal Characteristics of Fast Repetitive Oscillating Movement Invariant?“ Perceptual and Motor Skills 96, Nr. 3 (Juni 2003): 1027–39. http://dx.doi.org/10.2466/pms.2003.96.3.1027.
Der volle Inhalt der QuelleDissertationen zum Thema "Oscillating movement"
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Franc, Tadeáš. „Návrh pendlovací hlavy pro plošné navařování Inconelu 625“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443225.
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This diploma thesis deals with the structural design and production of a oscillating head for surface welding of a protective layer of Inconel® 625 superalloy on membrane walls. The design is preceded by a research for possible variants of the solution. Of the two designs, one was successfully manufactured and assembled, and incentives for future improvements were set. For easy optimization and testing of the device, an oscillating motion program was created in the LinMoT Talk 6.9 software. The production costs for the manufactured equipment were then calculated and the recommended selling price was determined, based on a general calculation formula. The result of the project is a functional device, a proposal for its control and a technical - economic evaluation of the production process.
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Houara, Komba Eymard. „Reconstitution of tribological accommodation mechanisms for greased high loaded oscillating bearings“. Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI018.
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Les roulements soumis à des mouvements oscillatoires et des charges élevées sont nécessaires pour le fonctionnement de nombreux mécanismes industriels (actionneurs, commandes d’avions, machines pour l’usinage, robots, chaînes d’assemblages, …). Ces roulements sont soumis à des pressions de contact locales extrêmement élevées avec des vitesses de roulement faibles qui ne permettent pas une lubrification adéquate des interfaces des premiers corps avec de l’huile. Les essais d’endurance sur les roulements ont permis la reconstitution des courbes de dégradation pendant la vie du roulement. Des analyses des surfaces, effectués à chaque phase de la vie du roulement ont permis aussi bien de suivre l’évolution de la topographie à l’interface entre les pistes et les éléments roulants. D’autre parte, des analyses numériques par éléments finis ont permis d’obtenir des informations sur les distributions des contraintes et des déformations. Le croisement des résultats expérimentaux et numériques a donc permis la reconstruction des mécanismes locaux d’accommodation. Dans le cas d’un roulement oscillant non graissé, les déplacements relatifs et les contraintes sont principalement accommodés aux interfaces des premiers corps en contact, ce qui accélère l’endommagement final du roulement. Dans le cas d’un roulement oscillant graissé, une partie des déplacements relatifs et contraintes est accommodée dans une sous couche qui se forme dans la peau des éléments roulants. Cette accommodation se manifeste par l’accumulation de déformations plastiques qui s’avèrent être aussi à l’origine de l’endommagement final du roulement. L’analyse des surfaces de contact des roulements oscillants graissés montre qu’il se forme, en présence de la graisse et très tôt dans la vie du roulement, une couche (troisième corps graisse/particule et TTS en surface de la piste) qui protège les surfaces en contact. D’autre part, une expertise de roulement ayant fonctionné sur un avion de de type A340 révèle une forte similarité entre ses faciès d’usure et ceux obtenus lors des essais d’endurance, et valide ainsi les mécanismes d’accommodation reconstitués. Enfin, des questions portant sur les effets de la quantité de graisse, du glissement des éléments roulants, et des pauses sur un essai donné sont aussi traitéesBearings subjected to oscillatory motions and high loads are necessary for the operation of several industrial mechanisms (actuators, aircraft controls, machining, robots, assembly lines, ...). These bearings are subjected to extremely high local contact pressures with low running speeds, which do not permit adequate lubrication of the interfaces of the first bodies with oil. Endurance tests perfomed on commercial bearings allowed at reconstructing the evolution of the degradation curves during the bearing life. Surface analyses carried out at each phase of the bearing life also allowed at following the evolution of the topography at the interface between the bearing raceways and the rolling elements. On the other hand, numerical analyses, by finite element method, have led to obtain information on the distributions of stresses and deformations. The dialogue between experimental and numerical results allowed the reconstruction of the local accomodation mechanisms. In the case of ungreased oscillating bearings, the relative displacements are mainly accommodated at the surfaces of the first bodies in contact, which accelerates the damage of the bearing. In the case of greased oscillating bearings, part of the relative displacements and stresses are accommodated at the subsurface of the rolling elements. This accommodation mechanism is manifested by the accumulation of plastic deformations which are at the origin of the final degradation of the bearing. The analysis of the contact surfaces of the raceways of the greased oscillating bearings shows as well that, in the presence of grease, a layer (third body mixture of grease and particles, and TTS on the track surface) protects the surfaces of the raceway and thus accommodates the other part of the displacements and stresses. On the other hand, the analysis of an airelon bearing, dismounted from an A340 type aircraft, revealed a strong similarity between its topographies and those obtained during the performed endurance tests, validateing the reconstructed accommodation mechanisms. Finally, questions about the effects of the amount of grease, sliding of the rolling elements, and pauses on a given test heve been discussed too
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Cevallos, Barragan Carlos. „THE RESONANCE OF BIOLOGICAL MOTION THROUGH VISUAL PERCEPTION IN THE HUMAN BRAIN“. Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/235472.
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Taking research as a tool to learn how new technology can develop new diagnosis and treatment methods in the physical field, takes place the education in motor sciences. On one hand, current research has shed light into novel methods to improve motor performance for athletes as well as for people learning new motor gestures. On the other hand it has also helped to improve treatment efficiency for people suffering motor cerebral lesions like: cerebrovascular attack (CVA) and cerebral palsy. This doctoral thesis addresses different protocols to analyze motor gestures and brain oscillations through visual perception.Our brain encompasses a changing symphony of oscillating activity throughout our lives. Up to the time we are born, we are ready to feel and move to interact with our world. Our senses develop rapidly and we start to perceive the world and learn. We visually perceive and process big amounts of information on a daily basis. At the same time we see movements from ourselves and from others in order to communicate and interact with our environment. We watch the world move. Moreover, from the links that exist between motor and sensory systems in human beings we may approach individual motor activity as a loop between a control (brain) over the effectors (muscles) which act, perceive and send the information back to the control source.The present group of works presented in this doctoral thesis is based on the correlation between human brain scalp activity, measured by means of electroencephalography (EEG) recordings, visual perception and its interpretation through different approaches.Doctorat en Sciences de la motricité
info:eu-repo/semantics/nonPublished
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Zaepffel, Manuel. „Etude des mécanismes fonctionnels de la préparation du mouvement : inférences à partir des potentiels électrophysiologiques de surface, intracorticaux et des rythmes cérébraux dans une tâche de saisie manuelle“. Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM5100.
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Pour un mouvement de saisie, le système moteur doit contrôler un certain nombre de paramètres pour produire une commande motrice adaptée aux propriétés de l'objet. La compréhension des mécanismes mis en jeu dans l’élaboration de cette commande motrice repose ainsi sur plusieurs questions. Quelle est la nature des paramètres traités par le système nerveux ? Quelles sont les structures corticales impliquées ? Quand et comment ces paramètres sont-ils traités ? Durant l’exécution du mouvement ou durant la phase de préparation qui précède son initiation ? Ces questions sont autant de problématiques abordées dans ce travail de thèse dont l'objectif général est d'apporter une meilleure compréhension, d'une part, de l'organisation fonctionnelle des processus mentaux qui lient la perception à l'action, et d'autre part, de la façon dont ces processus se traduisent au niveau neurophysiologique. Nos recherches reposent notamment sur la comparaison entre l'homme et le singe étudiés dans un contexte expérimental similaire et réalisant une tâche de saisie manuelle identique. L'ensemble de nos travaux ont orienté notre réflexion vers 3 axes principaux. Premièrement, ils nous ont permis de préciser les principes fonctionnels qui régissent la préparation des mouvements de saisie manuelle. Deuxièmement, ils nous ont conduits à identifier plusieurs composantes qui caractérisent les modulations du rythme bêta (13 -35 Hz) et à dégager les principaux facteurs régissant leur présence ou leur absence. En ce sens, nous avons proposé une hypothèse qui permet d’interpréter dans un cadre théorique unifié la majorité des études proposant des interprétations souvent contradictoires du rythme bêtaFor grasping, the motor system has to control several movement parameters to produce a motor command adapted to the object properties. The understanding of the mechanisms involved in the development of this motor command relies on several questions. What kinds of parameters are processed by the nervous systems? What are the cortical structures involved? When and how these parameters are processed? During the execution or during the preparation phase preceding movement initiation? All these questions are addressed in this thesis which general objective is to provide a better understanding of the mental processes linking perception to action and to clarify how the functional organization of these processes is reflected in the neurophysiological activity. Our research is based in particular on the comparison between humans and monkeys studied in a similar experimental setting and performing an identical reach-to-grasp task. The results of this work led us to focus our discussion on three main axes. First, they allowed to specify the functional principles underlying the preparation of grasping movements. Second, we identified several components that characterize the modulations of the beta rhythm (15-35 Hz) and pinpointed the main factors governing their presence or absence. In this sense, we propose a hypothesis for interpreting in a unified theoretical framework a large number of studies that often provide conflicting interpretations of this sensorimotor rhythm
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Dix, Annika [Verfasser], Elke van der [Akademischer Betreuer] Meer, Isabell [Akademischer Betreuer] Wartenburger und Roland [Akademischer Betreuer] Grabner. „Count on the brain : using EEG oscillations and eye movements to disentangle intelligent problem-solving in math / Annika Dix. Gutachter: Elke van der Meer ; Isabell Wartenburger ; Roland Grabner“. Berlin : Lebenswissenschaftliche Fakultät, 2016. http://d-nb.info/1081418508/34.
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Roy, Adam. „Music in Motion: A Metaphoric Mapping of Forces in Piano Concertos by Mozart and Schumann“. Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33009.
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In this thesis, I demonstrate the dynamic way in which musical processes can be described as metaphors. Using Steve Larson’s three main metaphors (gravity, inertia, and magnetism) as a starting point, I propose additional metaphors (friction, repulsion, momentum, wave, orbit, and oscillation) to analyze the first movements of Mozart’s Piano Concerto No. 20 in D minor, K 466 and Schumann’s Piano Concerto in A minor, op. 54. These metaphors provide a means to discuss points of convergence and divergence between the Classical style and the early-Romantic style. Additionally, most theorists of the energeticist tradition only discuss motion through prose; I introduce a way to represent these metaphors as musical examples. By focusing on the listener’s experience through musical motion, the model proposed in this thesis is useful, not only for the theorist, but for all who wish to communicate ideas about music in a dynamic way.
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Richter, Jan. „Řízení pohybu při přemisťování zavěšeného předmětu“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229188.
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The Diploma Thesis focuses on examination of most suitable optionsof movement regulation of pendent object from the perspective of various requirements on the course of the process as such. The environment of Matlab-Simulink was used for the analysis. The first part of the Thesis deals with the creation of the model of the whole system and creation of additional models of systems with similar, highly oscillating behaviour. The central part of the Thesis focuses on the design of suitable methods of movement regulation during translocation of the pendent object, which is tested on a simple model of travelling monkey. Four approaches to the problem solving were chosen: simple regulation by PID regulator, branched regulation, state regulation and predicative regulation. All solving options are being analysed and optimised and their results mutually compared according to requirements defined, such as: speed of the process, fluency of the movement, small pose overshoot or small angle of rope deflection.
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Beckstein, Pascal. „Methodenentwicklung zur Simulation von Strömungen mit freier Oberfläche unter dem Einfluss elektromagnetischer Wechselfelder“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232474.
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Im Bereich der industriellen Metallurgie und Kristallzüchtung treten bei zahlreichen Anwendungen, wo magnetische Wechselfelder zur induktiven Beeinflussung von leitfähigen Werkstoffen eingesetzt werden, auch Strömungen mit freier Oberfläche auf. Das Anwendungsspektrum reicht dabei vom einfachen Aufschmelzen eines Metalls in einem offenen Tiegel bis hin zur vollständigen Levitation. Auch der sogenannte RGS-Prozess, ein substratbasiertes Kristallisationsverfahren zur Herstellung siliziumbasierter Dünnschichtmaterialien, ist dafür ein Beispiel. Um bei solchen Prozessen die Interaktion von Magnetfeld und Strömung zu untersuchen, ist die numerische Simulationen ein wertvolles Hilfsmittel. Für beliebige dreidimensionale Probleme werden entsprechende Berechnungen bisher durch eine externe Kopplung kommerzieller Programme realisiert, die für Magnetfeld und Strömung jeweils unterschiedliche numerische Techniken nutzen. Diese Vorgehensweise ist jedoch im Allgemeinen mit unnötigem Rechenaufwand verbunden. In dieser Arbeit wird ein neu entwickelter Methodenapparat auf Basis der FVM vorgestellt, mit welchem sich diese Art von Berechnungen effizient durchführen lassen. Mit der Implementierung dieser Methoden in foam-extend, einer erweiterten Version der quelloffenen Software OpenFOAM, ist daraus ein leistungsfähiges Werkzeug in Form einer freien Simulationsplattform entstanden, welches sich durch einen modularen Aufbau leicht erweitern lässt. Mit dieser Plattform wurden in foam-extend auch erstmalig dreidimensionale Induktionsprozesse im Frequenzraum gelöst.
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„A study on the dynamics of periodical impact mechanism with an application in mechanical watch escapement“. Thesis, 2008. http://library.cuhk.edu.hk/record=b6074686.
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Among various non-smooth dynamic systems, the periodically forced oscillation system with impact is perhaps the most common in engineering applications. Usually it has an oscillator with fixed or unfixed stops. The dynamics becomes complicate due to the impact against the stops. Sometimes it leads to bifurcation and even turns to chaos. Its present applications include MEMS switch device, escapement in watch movement and so on.As a branch of mechanics, the multi-body dynamic system is well-studied. In particular, the non-smooth dynamical system attracts many researchers because of its importance and diversity. The main behaviours of such a system include contact (slip-stick motion), friction and impact. Although various models have been developed for these behaviours and their results are often satisfactory, the truth is that they are still far from completion. In the past twenty some years, various new methods have been developed. However, none of them is universally applicable. One of the difficulties is that there are a number of explicit discontinuities, such as: (a) Coulomb friction gives a discontinuous law for the forces as a function of velocities, and (b) The contact conditions give forces that are not only discontinuous in position, but also unbounded and give rise to discontinuities in the velocities.
This thesis presents a systematic study on the periodically forced oscillation system with impact. Various existing methods are discussed and compared. In particular, impulsive differential equation, Poincare map and perturbation theory are applied. Two practical cases are included: a first-order system and the Swiss lever escapement mechanism. The latter has significant engineering value as the Swiss level escapement is the key component of mechanical watch movement. The precision dynamic model has very high numerical accuracy in describing/predicting their dynamics. The research helps to optimize the design of a commercial product. The model is validated by means of experiment.
Fu, Yu.
Adviser: Du Ruxu.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3745.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 137-142).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
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Tsai, Ching-Lin, und 蔡慶霖. „The effects of high-frequency stimulation on subthalamic nucleus triggered by high-voltage-spindles in a closed-loop fashion on the development of beta-oscillations and movement abnormalities in hemi-Parkinsonian rats“. Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5rs3p7.
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Biewener, Andrew A., und Shelia N. Patek, Hrsg. Movement in Air. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198743156.003.0006.
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Aerial flight involves the same fluid mechanical principles as aquatic locomotion. However, the 800-fold lower density of air compared with water has marked consequences on the mechanisms of aerial locomotion. We examine the forces acting on a flying animal in which these fluid forces can be calculated. We then consider how basic features of the wings and body affect flight forces. Building on this understanding, we examine the power requirements associated with flight as a function of flight speed, based on conventional aerodynamics (i.e. steady airflow past non-oscillating wings, which applies to most engineered aircraft). Gliding flight is explained by steady-state theory and is discussed in this context. However, because flying animals must flap their wings to support weight and overcome drag, non-steady aerodynamic effects come into play. These non-steady aerodynamic effects are revealed by tracking the flow over a moving wing or by the use of robotic models.
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Cooper, Stephanie. The physiology of vocal cord movement. Herausgegeben von John Phillips und Sally Erskine. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198834281.003.0062.
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Kaell, Hillary. Christian Globalism at Home. Princeton University Press, 2020. http://dx.doi.org/10.23943/princeton/9780691201467.001.0001.
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Child sponsorship emerged from nineteenth-century Protestant missions to become one of today's most profitable private fundraising tools in organizations including World Vision, Compassion International, and ChildFund. Investigating two centuries of sponsorship and its related practices in American living rooms, churches, and shopping malls, this book reveals the myriad ways that Christians who don't travel outside of the United States cultivate global sensibilities. The book traces the movement of money, letters, and images, along with a wide array of sponsorship's lesser-known embodied and aesthetic techniques, such as playacting, hymn singing, eating, and fasting. It shows how, through this process, U.S. Christians attempt to hone globalism of a particular sort by oscillating between the sensory experiences of a God's eye view and the intimacy of human relatedness. These global aspirations are buoyed by grand hopes and subject to intractable limitations, since they so often rely on the inequities they claim to redress. Based on extensive interviews, archival research, and fieldwork, the book explores how U.S. Christians imagine and experience the world without ever leaving home.
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Lepora, Nathan F. Building blocks. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0013.
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This chapter introduces the “building blocks” section of the Handbook of Living Machines which explores the individual sensory and motor components that when pieced together can comprise a complete biological or artificial system. The first six chapters cover the senses of vision, audition, touch, taste, and smell (considered together as chemosensing, proprioception, and electrosensing). The remaining chapters review aspects of the biomimetics of animal movement. First, that biological muscle has many performance benefits compared with conventional electric, second, how oscillations in neural circuits can drive rhythmic movements, and finally the capacity of animal skin, in species such as geckos, to adhere to surfaces and support behaviors such as climbing.
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MacDonald, D. K. C. Noise and Fluctuations: An Introduction (Dover Books on Physics). Dover Publications, 2006.
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Witte, Hartmut, Martin S. Fischer, Holger Preuschoft, Danja Voges, Cornelius Schilling und Auke Jan Ijspeert. Quadruped locomotion. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0031.
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This chapter considers locomotion in living machines, focusing particularly on mammals and on the possibility of designing mammal-like quadrupedal robots. Locomotion is the movement of an organism or a machine from one place to the other, covering a defined minimal distance. In organisms, locomotion usually is driven by a central element and/or appendices. Vertebrates are characterized by the existence of a spine and the mechanics of an endoskeletal system. The amphibio-reptile type of vertebrate locomotion shows oscillations of the body stem mainly in the horizontal, which are coupled to the ground by legs with two long segments. The vertical oscillations of the body stem in the mammal type of quadrupedal locomotion are coupled to the ground by legs with three long segments. For any size of animal and any allometric relation between mass and ground reaction force the resonance mechanisms of gravitational and spring-mass-pendula are tuned to one each other. Elongated feet allow torque exchange with the substrate.
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Mauguière, François, und Luis Garcia-Larrea. Somatosensory and Pain Evoked Potentials. Herausgegeben von Donald L. Schomer und Fernando H. Lopes da Silva. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228484.003.0043.
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This chapter discusses the use of somatosensory evoked potentials (SEPs) and pain evoked potentials for diagnostic purposes. The generators of SEPs following upper limb stimulation have been identified through intracranial recordings, permitting the analysis of somatosensory disorders caused by neurological diseases. Laser activation of fibers involved in thermal and pain sensation has extended the applications of evoked potentials to neuropathic pain disorders. Knowledge of the effects of motor programming, paired stimulations, and simultaneous stimulation of adjacent somatic territories has broadened SEP use in movement disorders. The recording of high-frequency cortical oscillations evoked by peripheral nerve stimulation gives access to the functioning of SI area neuronal circuitry. SEPs complement electro-neuro-myography in patients with neuropathies and radiculopathies, spinal cord and hemispheric lesions, and coma. Neuroimaging has overtaken SEPs in detecting and localizing central nervous system lesions, but SEPs still permit assessment of somatosensory and pain disorders that remain unexplained by anatomical investigations.
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Herman, David. Explanation and Understanding in Animal Narratives. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190850401.003.0008.
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With chapter 6 having described the way norms for mental-state ascriptions operate in a top-down manner in discourse domains, chapter 7 explores how individual narratives can in turn have a bottom-up impact on the ascriptive norms circulating within particular domains. To this end, the chapter discusses how Thalia Field’s 2010 experimental narrative Bird Lovers, Backyard employs a strategic oscillation between two nomenclatures that can be used to profile nonhuman as well as human behaviors: (1) the register of action, which characterizes behavior in terms of motivations, goals, and projects; and (2) the register of events, which characterizes behavior in terms of caused movements that have duration in time and direction in space. In braiding together these two registers, Field’s text suggests not only how discourse practices can be repatterned, but also how such repatterning enables broader paradigm shifts—in this case shifts in ways of understanding cross-species encounters and entanglements.
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Wang, Bin. Intraseasonal Modulation of the Indian Summer Monsoon. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.616.
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The strongest Indian summer monsoon (ISM) on the planet features prolonged clustered spells of wet and dry conditions often lasting for two to three weeks, known as active and break monsoons. The active and break monsoons are attributed to a quasi-periodic intraseasonal oscillation (ISO), which is an extremely important form of the ISM variability bridging weather and climate variation. The ISO over India is part of the ISO in global tropics. The latter is one of the most important meteorological phenomena discovered during the 20th century (Madden & Julian, 1971, 1972). The extreme dry and wet events are regulated by the boreal summer ISO (BSISO). The BSISO over Indian monsoon region consists of northward propagating 30–60 day and westward propagating 10–20 day modes. The “clustering” of synoptic activity was separately modulated by both the 30–60 day and 10–20 day BSISO modes in approximately equal amounts. The clustering is particularly strong when the enhancement effect from both modes acts in concert. The northward propagation of BSISO is primarily originated from the easterly vertical shear (increasing easterly winds with height) of the monsoon flows, which by interacting with the BSISO convective system can generate boundary layer convergence to the north of the convective system that promotes its northward movement. The BSISO-ocean interaction through wind-evaporation feedback and cloud-radiation feedback can also contribute to the northward propagation of BSISO from the equator. The 10–20 day oscillation is primarily produced by convectively coupled Rossby waves modified by the monsoon mean flows. Using coupled general circulation models (GCMs) for ISO prediction is an important advance in subseasonal forecasts. The major modes of ISO over Indian monsoon region are potentially predictable up to 40–45 days as estimated by multiple GCM ensemble hindcast experiments. The current dynamical models’ prediction skills for the large initial amplitude cases are approximately 20–25 days, but the prediction of developing BSISO disturbance is much more difficult than the prediction of the mature BSISO disturbances. This article provides a synthesis of our current knowledge on the observed spatial and temporal structure of the ISO over India and the important physical processes through which the BSISO regulates the ISM active-break cycles and severe weather events. Our present capability and shortcomings in simulating and predicting the monsoon ISO and outstanding issues are also discussed.
Buchteile zum Thema "Oscillating movement"
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Stoicovici, Dinu Ioan. „Movement Regimes and Determining the Main Parameters of Oscillating and Vibrating Conveyors“. In Environmental and Human Impact of Buildings, 149–82. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57418-5_6.
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Shapiro, Ilya L., und Guilherme de Berredo-Peixoto. „Movement in a Potential Field: Oscillations“. In Undergraduate Lecture Notes in Physics, 133–62. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7825-6_7.
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Shaikh, Aasef, und Fajun Wang. „Approach to Saccadic Oscillations: Opsoclonus and Ocular Flutter“. In Eye Movements in the Critical Care Setting, 25–33. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70221-2_3.
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Bohn, Ralf. „Schreiben mit Licht“. In Bewegungsszenarien der Moderne, 93–109. Heidelberg, Germany: Universitätsverlag WINTER, 2021. http://dx.doi.org/10.33675/2021-82537264-6.
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In the 19th century, the stillness of movement during a photographic exposure required a staging based on academic traditions. Staging is the »spatialization« of a present absence – comparable to »writing« in the sense of Derrida. With the increasing mobility of camera techniques from the 20th century onwards, the focus is no longer on the reproduction of a moment, but instead on its performative invention.With the digital photography of the 21st century, a transformation from theatrical to functional staging takes place. The history of the writing scene of photography illustrates the interplay between concealment through technology and re-aestheticization, which with increasing oscillation turns into motor dizziness.
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Pfurtscheller, Gert. „Event-Related Desynchronization (ERD) and 40-Hz Oscillations in a Simple Movement Task“. In Oscillatory Event-Related Brain Dynamics, 357–66. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4899-1307-4_25.
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Berthoz, A., und P. P. Vidal. „Oscillations in the Control of Eye and Head Movements. Are They Due in Part to Supra-Brainstem Synchronising Oscillations?“ In Research and Perspectives in Neurosciences, 185–203. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-85148-3_11.
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Hosaka, Ryosuke, Toshi Nakajima, Kazuyuki Aihara, Yoko Yamaguchi und Hajime Mushiake. „Laterality of Gamma-Oscillations in Primate Supplementary Motor Area During Performance of Visually-Guided Movements“. In Advances in Cognitive Neurodynamics (IV), 165–69. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9548-7_23.
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Pylypaka, Sergiy, Mikola Klendiy und Tatiana Zaharova. „Movement of the Particle on the External Surface of the Cylinder, Which Makes the Translational Oscillations in Horizontal Planes“. In Lecture Notes in Mechanical Engineering, 336–45. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93587-4_35.
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„Timing an Oscillating Movement“. In Timing for Animation, 78–79. Routledge, 2013. http://dx.doi.org/10.4324/9780080951720-38.
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WHITAKER, H. „Timing an Oscillating Movement“. In Timing for Animation, 62–95. Elsevier, 2009. http://dx.doi.org/10.1016/b978-0-240-52160-2.00012-1.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Oscillating movement"
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Sun, Qin, Jian Qu, Jianping Yuan, Hai Wang und Scott M. Thompson. „Fluid Flow and Heat Transfer Characteristics of Micro Oscillating Heat Pipes With and Without Expanding Channels“. In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-3976.
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Abstract The oscillating heat pipe is considered a promising candidate for high-efficiency and compact thermal control for next-generation electronics. In this paper, the visualized flow and heat transfer characteristics of two silicon-based micro oscillating heat pipes (micro-OHPs) with expanding and straight channels, respectively, were experimentally investigated. The overall size of these two micro-OHPs are both 28 mm × 23 mm × 1.025 mm and have thirty rectangular cross-section channels. The hydraulic diameter of parallel direct channel is 332.4 μm, while they are about 364.4 and 287.0 μm at the two ends of expanding channel, respectively. R141b was used as the working fluid with the volumetric filling ratio of 50%. Inside these two micro-devices, the fluid oscillating motion, including unidirectional movement and intermittent stopovers, was observed at the quasi-steady oscillation state, accompanied by bubbly flow, slug flow and annular/semi-annular flow in microchannels. The micro-OHP with expanding channels possessed better thermal performance and could achieve ephemeral circulation flow, while poorer heat transfer performance occurred for the micro-OHP with straight channels due to more localized slug/plug oscillations and intermittent stopovers. The oscillating amplitudes of liquid slugs are presented to estimate the flow behavior of working fluid inside micro-OHPs. The introduction of expanding channels in a micro-OHP is beneficial for realizing the more robust oscillating motion of liquid slugs with larger oscillating amplitudes for heat transfer enhancement.
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Pung, Justin, und Darrell S. Crowe. „Tracking Shock Movement on the Surface of an Oscillating, Straked Delta Wing“. In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-2318.
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Kobayashi, Hiroshi. „Annular Cascade Study of Low Back-Pressure Supersonic Fan Blade Flutter“. In ASME 1989 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1989. http://dx.doi.org/10.1115/89-gt-297.
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Low back-pressure supersonic fan blade flutter in the torsional mode was examined using a controlled-oscillating annular cascade test facility. Precise data of unsteady aerodynamic forces generated by shock wave movement due to blade oscillation and the previously measured data of chordwise distributions of unsteady aerodynamic forces acting, on an oscillating blade were joined, and then the nature of cascade flutter was evaluated. These unsteady aerodynamic forces were measured by direct and indirect pressure measuring methods. Our experiments covered a range of reduced frequencies based on a semi-chord from 0.0375 to 0.547, 6 interblade phase angles and inlet flow velocities from subsonic to supersonic flow. The occurrence of unstalled cascade flutter in relation to reduced frequency, interblade phase angle and inlet flow velocity was clarified including the role of unsteady aerodynamic blade surface forces on flutter. Reduced frequency of the flutter boundary increased greatly when the blade suction surface flow became transonic flow. Interblade phase angles which caused flutter were in the range from 40° to 160° for flow fields ranging from high subsonic to supersonic. Shock wave movement due to blade oscillation generated markedly large unsteady aerodynamic forces which stimulated blade oscillation.
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Aotsuka, Mizuho, Toshinori Watanabe und Yasuo Machina. „Role of Shock and Boundary Layer Separation on Unsteady Aerodynamic Characteristics of Oscillating Transonic Cascade“. In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38425.
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The unsteady aerodynamic characteristics of an oscillating compressor cascade composed of Double-Circular-Arc airfoil blades were both experimentally and numerically studied under transonic flow conditions. The study aimed at clarifying the role of shock waves and boundary layer separation due to the shock boundary layer interaction on the vibration characteristics of the blades. The measurement of the unsteady aerodynamic moment on the blades was conducted in a transonic linear cascade tunnel using an influence coefficient method. The cascade was composed of seven DCA blades, the central one of which was an oscillating blade in a pitching mode. The unsteady moment was measured on the central blade as well as the two neighboring blades. The behavior of the shock waves was visualized through a schlieren technique. A quasi-three dimensional Navier-Stokes code was developed for the present numerical simulation of the unsteady flow fields around the oscillating blades. A k-ε turbulence model was utilized to adequately simulate the flow separation phenomena caused by the shock-boundary layer interaction. The experimental and numerical results complemented each other and enabled a detailed understanding of the unsteady aerodynamic behavior of the cascade. It was found that the surface pressure fluctuations induced by the shock oscillation were the governing factor for the unsteady aerodynamic moment acting on the blades. Such pressure fluctuations were primarily induced by the movement of impingement point of the shock on the blade surface. During the shock oscillation the separated region caused by the shock boundary layer interaction also oscillated along the blade surface, and induced additional pressure fluctuations. The shock oscillation and the movement of the separated region were found to play the principal role in the unsteady aerodynamic and vibration characteristics of the transonic compressor cascade.
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Kobayashi, Hiroshi. „Effect of Shock Wave Movement on Aerodynamic Instability of Annular Cascade Oscillating in Transonic Flow“. In ASME 1988 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1988. http://dx.doi.org/10.1115/88-gt-187.
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Effects attributable to shock wave movement on cascade flutter were examined for both turbine and compressor blade rows, using a controlled-oscillating annular cascade test facility and a method for accurately measuring time-variant pressures on blade surfaces. Nature of the effects and blade surface extent influenced by the shock movement were clarified in a wide range of Mach number, reduced frequency and interblade phase angle. Remarkable unsteady aerodynamic force was generated by the shock movement and it significantly affected the occurrence of compressor cascade flutter as well as turbine one. For turbine cascade the interblade phase angle remarkably controlled the effect of the force, while for compressor one the reduced frequency dominated it. The chordwise extent on blade surface influenced by the shock movement was suggested to be about 6% chord length.
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Allen Demers, Louis-Alexis, und Cle´ment Gosselin. „Kinematic Design of Mechanisms for the Control of an Oscillating Wing“. In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34580.
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This work is part of a project which aims at the development of underwater generators using oscillating wings. One of the important challenges in the design of a system collecting the kinetic energy of a fluid is the transformation of this energy into electric power [1]. Since it is not possible to pass directly from the movement of a fluid to electric power, it is necessary to conceive an intermediate mechanical system. Its function is to convert the kinetic energy of the fluid into kinetic energy of a mechanism capable of converting kinetic energy into electric power. In this work, the mechanical system also has an additional function, i.e., to guide the orientation of the blades (wings) throughout the cycle of movement in order to maximize the efficiency.
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Silva, Elinaldo Santos, und Sergio N. Bordalo. „Experimental Study of Two-Phase Flow in an Oscillating Vertical Pipe“. In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78323.
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Two-phase vertical flows are of utmost importance for petroleum production, since underground petroleum reservoirs produce oil and gas simultaneously, which must flow together upward to the sea floor through wells, and from these to the production floating units through suspended pipes (risers). Along the pipelines, the mixture of oil and gas may develop several flow patterns — such as bubble, slug, churn and annular flow. These physical configurations present specific characteristics that demand distinct modeling of the head loss as a function of the flow rate. The correct characterization of the flow patterns, under given operational conditions, is fundamental to the modeling of the dynamics of the flow and to the relation between head loss and flow rate. In the literature, most studies on the establishment of the flow patterns have been carried with water and air, and have been restricted to the case of static pipes, while production risers are in constant movement due to the action of waves, sea currents and the displacement of the floating production unit. In the present work, an experimental study of vertical two-phase flow of water and air is conducted with the oscillatory movement of a long and slender flexible vertical pipe of 8,0 m of length and 25,4 mm of diameter. The head loss is measured for different frequencies of oscillation. Comparisons are made between the static and oscillating pipe, with regard to the flow patterns and head losses. The effect of the frequency of oscillation is detected.
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Yu, Chunrong, Yulong Ji, Lilin Chu, Zongyu Wang, Yadong Li und Hongbin Ma. „The Phenomenon of Unidirectional Circulating Flow in an Oscillating Heat Pipe“. In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-3937.
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Abstract The phenomena of two different types of unidirectional circulating flow pattern in a copper oscillating heat pipe (OHP) were firstly discovered and investigated. The OHP has six turns and three sections: evaporator, condenser and adiabatic sections with lengths of 40 mm, 64 mm, and 51 mm, respectively. R152a was used as the working fluid, the effects of the tilt angle from 0° to 90° and the heat input on the flow and heat transfer of the working fluid in OHP was studied. The experimental results showed that (1) the OHP charged with R152a can form a unidirectional circulating flow at any tilt angle under certain heat input, and the unidirectional circulating flow become steady as the heat input increases; (2) another type of circulating flow was found in the same OHP as the heat input increased to a relative high level, the difference between the two types of circulating flow is that the liquid slugs move forward with or without back forward oscillating movement; (3) the unidirectional circulating flow of the working fluid without back forward oscillating movement in the OHP significantly enhance the heat transfer of OHP.
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Wirgart, Jonas Erik, Takayuki Terai und Naoto Kasahara. „Crack Propagation due to Movement or Size Change of Hot Spot in Pipe“. In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97317.
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Thermal fatigue may occur downstream from mixing tee junctions where hot and cold water are turbulently mixed. Depending on the momentum of the incoming flows, different characteristic eddies are formed which create a local hot spot on the inner surface of the pipe. The hot spot have an unstable discrete boundary that spatially oscillates and this creates an oscillating multidimensional thermal load that induces high cycle thermal fatigue. To predict the thermal fatigue lifetime of a pipe subject to this kind of thermal load, transient FEM simulations with an ideal hot spot in two and three dimensions were conducted. The crack lengths induced by the frequency of the oscillating boundary was analysed and it was found that the most harmful frequency for a pipe is in the nondimensional frequency of 0.01 to 1.0. Additionally, the simulation method was validated against data publications of FAT3D experiments. The simulations have been compared to the current proposed Japanese design code for mixing tee junctions. The study shows that this multidimensional effect induces larger crack lengths than the current design code. The reason of this was analysed.
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Gan, Jiuliang, Toshinori Watanabe und Takehiro Himeno. „Effect of Shock Wave Behavior on Unsteady Aerodynamic Characteristics of Oscillating Transonic Compressor Cascade“. In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-59416.
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Abstract The unsteady behavior of the shock wave was studied in an oscillating transonic compressor cascade. The experimental measurement and corresponding numerical simulation were conducted on the cascade with different shock patterns based on influence coefficient method. The unsteady pressure distribution on blade surface was measured with fast-response pressure-sensitive paint (PSP) to capture the unsteady aerodynamic force as well as the shock wave movement. It was found that the movement of shock waves in the neighboring flow passages of the oscillating blade was almost anti-phase between the two shock patterns, namely, the double shocks pattern and the merged shock pattern. It was also found that the amplitude of the unsteady pressure caused by the passage shock wave was very large under the merged shock pattern compared with the double shocks pattern. The stability of blade vibration was also analyzed for both shock patterns including 3-D flow effect. These findings were thought to shed light on the fundamental understanding of the unsteady aerodynamic characteristics of oscillating cascade caused by the shock wave behavior.