Дисертації з теми "Cavitation bubble dynamics"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-29 дисертацій для дослідження на тему "Cavitation bubble dynamics".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Salhan, A. "Dynamics of an explosion bubble close to a structure." Thesis, University of Brighton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323638.
Повний текст джерелаLind, Steven John. "A numerical study of the effect of viscoelasticity on cavitation and bubble dynamics." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/46566/.
Повний текст джерелаWalters, Michael. "An investigation into the effects of viscoelasticity on cavitation bubble dynamics with applications to biomedicine." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/73461/.
Повний текст джерелаDiaz, Mario Alfonso. "High-Frequency Ultrasound Drug Delivery and Cavitation." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1050.
Повний текст джерелаMontes, Quiroz William. "Étude expérimentale de la stabilité d'une bulle unique de cavitation acoustique : application à la nucléation de la glace déclenchée par cavitation." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2014. http://www.theses.fr/2014EMAC0002/document.
Повний текст джерелаThis study of the stability of an acoustic cavitation bubble is part of an ANR project started in September 2009 (SONONUCLICE ANR-09-BLAN-0040-02). It takes place in the continuity of the works on the optimization process of lyophilisation of pharmaceutical products conducted by the “Transferts couplés de matière et de chaleur” team of LAGEP (ESCPE/UCB, Lyon) laboratory, which is the project’s team leader, and the studies of ultrasound-assisted crystallization in the RAPSODEE Centre. The application of power ultrasound into liquids produces thousands of bubbles. This phenomenon is called acoustic cavitation. The bubbles formed don’t have the same size, their oscillations are not in phase, and their spatial density in the fluid is not homogeneous: this phenomenon is very complex and involves multiple variables very difficult to isolate. Even if this phenomenon is chaotic, it allows to observe macroscopic effects on the nucleation and crystal growth of ice in undercooled solutions. These effects have a capital importance for industrial applications such as freezing and lyophilisation (also called freeze drying). Although ultrasound has a noticeable influence on crystallization, the origin of these effects remains unclear. The multi-bubble approach doesn’t give any hint on the microscopic mechanisms involved. In order to isolate the main actor of these effects, this study aims at isolating a single cavitation bubble. To do that, a cubic levitation cell made of optical glass was build. In this cell, an acoustic pressure is applied by a piezoelectric glued to the bottom’s external face of the cell. With this cell is possible to rebuild all the oscillations states of the bubble, and in combination with our optical system we can see the bubble’s dynamics and its stages like: expansion, collapse and rebounds. For the crystallization part of this study, a crystal’s detection system was developed. It is based on the variations of the bubble’s periodicity (measured by a microphone pill) introduced by the sudden appearance of a foreign body in its vicinity. This method requires the correlation of the signals from a filtered microphone and the harmonics signals from a microphone, in order to known the oscillation state of the bubble and detect variations on the bubble’s dynamics. Experiments of bubble perturbations by a thin wire were made. The detection system was used to trigger the image recording of a fast camera, in order to capture the final moments of the bubble. This method should be allowing the early detection of new crystals in the proximity of the bubble. Around the levitation cell, various systems have been developed. A degassing and filling system for the cavitation cell allow us to work with degased water around the 20 % of its saturated concentration of air. An illumination system based in a power LED and a set of optical lenses was used to view the bubble correctly
Carleton, James Richard. "The Effect of Electrohydraulic Discharge on Flotation Deinking Efficiency." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6971.
Повний текст джерелаBossio, Castro Alvaro Manuel. "Lagrangeovský model pohybu kavitační bubliny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401546.
Повний текст джерелаBienaime, Diane. "Embolie dans les plantes : dynamique de l'invasion d'air dans des réseaux hydrauliques naturels et artificiels sous pression négative." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY056/document.
Повний текст джерелаTo assure the transport from the roots to the leaves, vascular plants create strong depressions in the sap, next to -200 bars. This depression pulls the water column contained by the tree vascular system. The water cohesion keeps the sap under liquid state. This metastable state can breaks: cavitation bubbles appear. They create an air plug inside the plant hydraulic network and impede sap flow. This phenomena called embolism could lead to the plant death by preventing the sap transport.This thesis is dedicated to the air invasion into hydraulics networks under negative pressure. First, we study the leaf embolism. We developed a new technique which allows us to record the spatial propagation of embolism in leaves hydraulic network. We show that the embolism propagates by steps from biggest veins to smallest veins.Next, in order to understand the underlying physical laws, we use two model systems. We build artificial networks in a hydrogel which mimics the sap flow characteristics. After the relaxation of the negative pressure in the network by the nucleation of a bubble, we observe surface oscillations and the slow growth of the bubble. This growth is linked to the water transport through the hydrogel and can reach a stationary regime.As we are not able to reproduce all the characteristics of the leaf network with the hydrogel, we create a computer modeling based on the Ohm analogy between hydraulics networks and electrical circuits. We reproduce the specific features of the xylem which transport the sap: the conduits are linked by pits, small valves which limit the progression of the embolism. We were able to recover the distinctiveness steps in embolism.Finally, we discuss the application of the preceding results to wood and we present some results on Pinus sylvestris
Sarkar, Prasanta. "Simulation de l'érosion de cavitation par une approche CFD-FEM couplée." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI016/document.
Повний текст джерелаThis research is devoted to understanding the physical mechanism of cavitation erosion in compressible liquid flows on the fundamental scale of cavitation bubble collapse. As a consequence of collapsing bubbles near solid wall, high pressure impact loads are generated. These pressure loads are believed to be responsible for the erosive damages on solid surface observed in most applications. Our numerical approach begins with the development of a compressible solver capable of resolving the cavitation bubbles in the finite-volume solver YALES2 employing a simplified homogenous mixture model. The solver is extended to Arbitrary Lagrangian-Eulerian formulation to perform fluid structure interaction simulation with moving mesh capabilities. The material response is resolved with the finite element solver Cast3M, which allowed us to perform one-way and two-way coupled simulations between the fluid and solid domains. In the end, we draw comparisons between 2D and 3D vapor bubble collapse dynamics and compare them with experimental observations. The estimated pressure loads on the solid wall and different responses of materials for attached and detached bubble collapses are discussed. Finally, the damping of pressure loads by different materials is identified with two-way coupled fluid-structure interaction
Guillet, Thibault. "Cavitation & Supercavitation : From a bluff to a stable streamlined projectile." Thesis, Institut polytechnique de Paris, 2019. http://www.theses.fr/2019IPPAX007.
Повний текст джерелаSupercavitation uses the phase transition liquid-gaseous, triggered by the fast motion of a projectile, to streamline its shape and reduce its drag. In this thesis, we address several aspects of supercavitation: cavitation triggered by acceleration in a confined geometry, drag reduction induced by the air cavity and the stability of the trajectory of such streamlined projectiles. More precisely, we first study both experimentally and theoretically the growth of cavitation bubbles. After showing that their growth is uniquely possible in a deformable container, we prove, in the case of a transient pressure drop, that the dynamic of the bubbles follows the Rayleigh-Plesset equation and that their maximum radius can analytically be predicted. If the velocity of the projectile is high enough, the bubbles grow and coalesce to form a large bubble pinned at the surface of the projectile and located in its wake: this is the so-called supercavitation regime. We show that this regime can be mimicked in "regular", low velocity, hydrodynamic tunnel via air injection at the surface of the projectile. In this set-up, we demonstrate that the relative size of the bubble is governed by an unique dimensionless parameter. In the case of a sphere, we measure the drag modification induced by the presence of the bubble. Finally, the overall system {sphere + bubble} is analogous to a inhomogeneous streamlined projectile. We show that such streamlined projectiles can follows curved paths, following their impact on water. We demonstrate, both experimentally and theoretically, that the morphology of their trajectory is governed by the impact velocity, their shape and the position of the center of mass of the projectile
Nickaeen, Mehrdad [Verfasser], Jeanette [Gutachter] Hussong, and Harald [Gutachter] Kruggel-Emden. "Spatially resolved simulations of the non-equilibrium cavitation bubble dynamics including vapor and air transport / Mehrdad Nickaeen ; Gutachter: Jeanette Hussong, Harald Kruggel-Emden ; Fakultät für Maschinenbau." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1205976388/34.
Повний текст джерелаVincent, Olivier. "Dynamique de bulles de cavitation dans de l'eau micro-confinée sous tension. Application à l'étude de l'embolie dans les arbres." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00807749.
Повний текст джерелаPereira, Pedro Augusto Fernandes. "Estudo do fenômeno de formação e colapso de macro cavidades em líquidos." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18147/tde-05062014-095014/.
Повний текст джерелаCavitation and bubble dynamics are fairly recurring topics in literature, mostly due to their effects in various types of phenomena such as heat transfer and flow in pipes. Considering liquid phases, it is known that these cavity structures are normally associated with the metastable equilibrium, reached due to local pressure drop or overheating of a pure substance (or nearly so). In these cases, the phase change require a startup via some appropriate mechanism, which generates a fast sequence of phenomena. Although commonly associated with damage, recently several studies shown practical applications of these topics, and a still little explored field emerged, which is the field of macro cavities. These cavities can be generated by heating water at a low pressure, under specific conditions, creating an explosive sequences and forming piston like movements for the water inside a properly scaled casing. This phenomenon appears to be similar in many aspects to micro cavities, more specifically for cavities near free surfaces, although, without doubt, on a much larger scale. The mentioned aspects were filmed with high-speed cameras and the main features were compared with those observed in micro scale. Several tests have been developed to better understand the dynamics of the formation and collapse of these structures, especially taking into account a more one-dimensional behavior to the evolution of the bubble. Through various approximations, and analysis of different assumptions for the variation of pressure and the resistance force, analytical and numerical solutions were obtained for the force exerted on the bottom of the container and the expansion and collapse of bubbles over time. The proposed solutions in comparison with experimental data showed good agreement between each other suggesting that the fundamental aspects of the dynamics of the cavity were properly considered and quantified.
Pham, Hong Son. "Investigation of the supercritical CO2 cycle : mapping of the thermodynamic potential for different applications; further understanding of the physical processes, in particular through simulations and analysis of experimental data." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4338.
Повний текст джерелаThis study first evaluates the thermodynamic performance of the supercritical CO2 (sc-CO2) cycle in a large range of heat source temperature, with a focus on the nuclear applications; a thermal efficiency of 45.7% is reported for a Sodium-cooled Fast Reactor. Second, CFD simulations have been performed on a small scale sc-CO2 compressor and results have been confronted positively with the experimental data. Simulation results on a real scale compressor have then revealed some particularities during the compression of a real fluid, providing feedbacks for the component design. In addition, a reliable performance maps approach has been proposed for the sc-CO2 compressor and validated using the CFD results. Finally, an investigation of bubble collapse in the liquid CO2 near the critical point has disclosed the likely absence of detrimental effects. As such, risks of cavitation damage should be low, favoring the compressor operation in the liquid region for cycle efficiency improvement
Krefting, Dagmar. "Untersuchung von Einzel- und Mehrblasensystemen in akustischen Resonatoren." Doctoral thesis, [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=97074675X.
Повний текст джерелаBachmann, Mathieu [Verfasser]. "Dynamics of cavitation bubbles in compressible two-phase fluid flow / Mathieu Bachmann." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1036241467/34.
Повний текст джерелаWilliams, P. M. "The formation and activity of bubbles during cavitation produced by dynamic stressing." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636624.
Повний текст джерелаLauer, Eric [Verfasser]. "Numerical simulation and investigation of high-speed bubble-dynamics in cavitating flow. / Eric Lauer." München : Verlag Dr. Hut, 2013. http://d-nb.info/1045989126/34.
Повний текст джерелаKrumenacker, Laurent. "Contribution à la prévision de l'érosion de cavitation à partir de simulations numériques : proposition d'un modèle à deux échelles pour l'estimation du chargement imposé en paroi par le fluide." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENI006/document.
Повний текст джерелаDuring the life's cycle of a hydraulic installation, the occurrence of cavitation can cause significant damages on the material's surface. The quantification of the cavitation intensity in different geometry can be useful to get better designs for new installations, but also to improve the operating and to optimize maintenance of existing equipments. The development of universal laws of similarity from experiments is difficult due to the large number of parameters governing cavitating flows. With the increase of computational performance, numerical simulations offer the opportunity to study this phenomenon in various geometries. The main difficulty of this approach is the scale's difference existing between the numerical simulations U-RANS used to calculate the cavitating flow and mechanisms of bubble's collapse held responsible for damages on the solid. The proposed method in this thesis is based on a textbf{post-treatment} of the textbf{U-RANS} simulations to characterize a distribution of bubbles and to simulate their behavior at lower spatial and temporal scales. Our first objective is to make explicit a system of equations corresponding to phenomena occurring locally in the two-phase flow. This work leads to the development of mixture variables taking into account the presence of non-condensable gases in the fluid. Assumptions are taken to make the system, after using the Reynolds averaging procedure, equivalent to those, using a homogeneous approach, implemented in the unsteady cavitating flows solvers previously developed in the laboratory. The characterization of bubbles made by this post-treatment takes into account both the surface tension and the presence of non-condensable gases. The development of a solver for the simulation of the dynamic of a bubble cloud is started. It aims to take into account both the interactions between bubbles and non-spherical deformations with a potential method. First results of these simulations are presented and small non-spherical deformations occurring during the collapse can be observed. Finally, we propose a chained method between these two systems initializing the bubble dynamic solver with results of U-RANS simulations. The energy emitted during the implosion of bubbles impacting the solid surface is calculated. So the aggressiveness of the flow on the material can be characterized. We apply this method on different flows to compare numerical and experimental results
Scognamiglio, Chiara. "Dynamique de bulles de cavitation dans des systèmes micro-confinés." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4126.
Повний текст джерелаThe present thesis focuses on cavitation process, meaning nucleation and dynamics of a bubble within a liquid as a result of pressure decrease. In particular, we investigate the growth of the vapor phase in micrometric volumes of water confined by a poro-elastic material. In systems where water is encapsulated in a porous medium, molecules can evaporate from the pores resulting in a remarkable pressure reduction and bubbles nucleation. Once a vapor bubble nucleates, it can trigger within few microseconds the appearance of other bubbles in the neighbor cavities, activating an ultra-fast avalanche-like phenomenon. We resolved the dynamics and acoustics of cavitation bubbles, in case of singles or multiple nucleation events. The realization of an innovative device where water is encapsulated between a porous material and a glass window opens the way for metastable water investigation. A second part of the manuscript is devoted to a new project where microfluidics and biology are combined and applied to drug delivery. The device consists of an artificial blood vessel in communication with the target tissue accommodated in a purposely designed compartment (tissue-on-a-chip). The walls of the microfluidic channel mimicking the vessel are lined with endothelial cells to reproduce the actual walls of in vivo blood vessels. This device allows to investigate the effects of ultrasound-activated bubbles on the blood vessels wall
Münster, Filip. "Numerické řešení dynamiky kavitační bubliny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-387731.
Повний текст джерелаPellegrin, Mathieu. "Nucléation et dynamique de bulles de cavitation dans des liquides confinés sous tension : expériences dans des systèmes microfabriqués et simulations de la dynamique moléculaire." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4061.
Повний текст джерелаIn this work, we have been interested in the cavitation process of vapor bubbles in a confined and stretched liquid. We have followed two complimentary points of view: numerical simulation and biomimetical experiments. For the numerical study we have used molecular dynamics simulations of a liquid confined in a solid cell. This method allows us to study precisely the effect of the interaction between the solid and the liquid (contact angle), and also the geometrical properties on the nucleation of vapor bubbles. We have also studied the interaction between two neighboring cells, and by comparing with a model, we have shown a correlation between two cavitation events and the important parameters taking place in this phenomenon. For the experimental study, we have used polymer hydrogel devices inspired from natural systems (ferns sporangia). This method allows us to study a system having almost the same mechanical properties as the natural one, and showing the possibility to control its geometry. We have shown that the wall thickness between the cells can control the propagation properties from isolated cavitation to grouped propagation (up to several hundreds of bubbles). The cell size controls the propagation velocity, up to values of 800 m/s. We have shown by comparing with an acoustical model the important parameters that control this phenomenon
d'Agostino, Luca. "Experimental and Theoretical Study on Cavitation Inception and Bubbly Flow Dynamics: I. Design, Development and Operation of a Cavitation Susceptibility Meter. II. Linearized Dynamics of Bubbly and Cavitating Flows with Bubble Dynamics Effects." Thesis, 1987. https://thesis.library.caltech.edu/1150/1/Agostino_1_1987.pdf.
Повний текст джерелаThe first and main part of this work presents the design, development and operation of a Cavitation Susceptibility Meter based on the use of a venturi tube for the measurement of the content of active cavitation nuclei in water samples. The pressure at the venturi throat is determined from the upstream pressure and the local flow velocity without corrections for viscous effects because the flow possesses a laminar potential core in all operational conditions. The detection of cavitation and the measurement of the flow velocity are carried out optically. The apparatus comprises a Laser Doppler Velocimeter for the measurement of the flow velocity and the detection of cavitation, a custom-made electronic Signal Processor for real time generation and temporary storage of the data and a computerized system for the final acquisition and reduction of the collected data. The various steps and considerations leading to the present design concept are discussed in detail and the implementation of the whole system is described in order to provide the all the information necessary for its calibration and operation. Finally, the results of application of the Cavitation Susceptibility Meter to the measurement of the water quality of tap water samples are presented and critically discussed with reference to other similar or alternative methods of cavitation nuclei detection and to the current state of knowledge on cavitation inception.
The second part of the present work presents the results of an investigation on the linearized dynamics of two-phase bubbly flows with the inclusion of bubble dynamics effects. Two flow configurations have been studied: the time dependent one-dimensional flow of a spherical bubble cloud subject to harmonic excitation of the far field external pressure and the steady state two-dimensional flow of a bubbly mixture on a slender profile of arbitrary shape. The inclusion of bubble dynamic damping and of the relative motion between the two phases and the extension of the results to the case of arbitrary excitation are discussed when examining the second flow configuration. The simple linearized dynamical analysis developed so far clearly demonstrates the importance of the complex phenomena connected to the interaction of the dynamics of the bubbles with the flow and provides an introduction to the study of the same flows with non-linear bubble dynamics.
Ceccio, S. L. "Observations of the dynamics and acoustics of travelling bubble cavitation." Thesis, 1990. https://thesis.library.caltech.edu/4897/1/Ceccio_sl_1990.pdf.
Повний текст джерелаLee, Min-Wei, and 李旻威. "Computation of Nonlinear Dynamics of a Spherical Cavitation Cloud with Bubble Size Distribution." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/39445352008809076676.
Повний текст джерела國立成功大學
機械工程學系
87
The nonlinear dynamics of a spherical bubble cloud with nuclei size distribution are studied numerically but the spectrum of nuclei is assumed uniform initially. Employing a nonlinear continuum bubbly mixture model with consideration of the presence of bubbles of different sizes. This model is then coupled with the Rayleigh-Plesset equation for the dynamics of bubbles. A numerical method based on the integral representation of the mixture continuity and momentum equations in the Lagrangian coordinates is developed to solve this set of integro-differential equations. Computational results show that the nuclei size distribution has significant effects on the cloud dynamics In comparison to the results for a single bubble size. One important effect is that the bubble collapse is always initiated near the surface of the cloud, even if the cloud has a very small initial void fraction. This effect has an important consequence, namely that the geometric focusing of the bubbly shock waves always a part of the nonlinear dynamics associated with the collapse of spherical cloud with nuclei size distribution.
Yang, Xinmai. "Investigation of bubble dynamics and heating during focused ultrasound insonation in tissue-mimicking materials." Thesis, 2010. https://hdl.handle.net/2144/1368.
Повний текст джерелаKoch, Max. "Laser cavitation bubbles at objects: Merging numerical and experimental methods." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1516-B.
Повний текст джерелаSöhnholz, Hendrik. "Temperatureffekte bei der lasererzeugten Kavitation." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0023-3E00-F.
Повний текст джерелаSchanz, Daniel Alexander. "Molekulardynamische Untersuchungen zur Binnendynamik kollabierender Blasen." Doctoral thesis, 2008. http://hdl.handle.net/11858/00-1735-0000-0006-B48E-A.
Повний текст джерела