Numerical Simulation of the Interaction Between an External Flow, Laminar Or Turbulent, and Liquid/vapor Phase Change

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (116 download)

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Book Synopsis Numerical Simulation of the Interaction Between an External Flow, Laminar Or Turbulent, and Liquid/vapor Phase Change by : Elena-Roxana Popescu (docteur en mécanique des fluides).)

Download or read book Numerical Simulation of the Interaction Between an External Flow, Laminar Or Turbulent, and Liquid/vapor Phase Change written by Elena-Roxana Popescu (docteur en mécanique des fluides).) and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a launcher tank, the cryogenic fuel can suffer a liquid/vapor phase change due to a thermal gradient induced by solar radiation or by engines residual thermal diffusion. The quantity of vapor released by the phase change process can highly increase the internal pressure. Due to a poor knowledge of these phenomena, at present, the operations led to regulate the internal pressure induce fuel loss. It is therefore of great importance to investigate the liquid/vapor phase and the physical processes taking place at the interface. This is the context of the present thesis, thattakes place in an effort to extract better understanding of the above underlined phenomena by means of Direct Numerical Simulation (DNS). The work is split into three studies : the interaction between a liquid pool at saturation and an external flow of subcooled or superheated vapor, both in laminar and turbulent regime flows, and the interaction between natural convection mouvements and liquid/vapor phase change. Firstly, the laminar regime flow is investigated. In this framework, a parametric study is conducted with the objective of finding behaviour laws for the heat transfer and the friction coefficient at the interface between a static liquid pool at saturation temperature and a laminar boundary layer flow of vapor. Both vaporization and condensation are studied. The second project was on the numerical simulation of a turbulent boundary layer flow of superheated vapor interacting with the velocity field induced by vaporization. To this extent, a turbulent fluctuations injector is implemented and validated for the spatial development of a boundary layer flow over a flat plate with heat transfer. A study on the influence of the velocity field induced by vaporization on the Nusselt number, the friction coefficient, the Stanton number and the turbulent quantities is conducted. Finally, we lead a preliminary numerical study on a configuration describing the interaction between natural convection flow and liquid/vapor phase change in a cryogenic tank. A new solver is implemented in the in house code to account for the density variations in the liquid. Preliminary results are obtained on the influence of the Grashof number on the thermal flux at the liquid/vapor interface.

Numerical Simulation of Unsteady Flows and Transition to Turbulence

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Publisher : Cambridge University Press
ISBN 13 : 9780521416184
Total Pages : 536 pages
Book Rating : 4.4/5 (161 download)

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Book Synopsis Numerical Simulation of Unsteady Flows and Transition to Turbulence by : O. Pironneau

Download or read book Numerical Simulation of Unsteady Flows and Transition to Turbulence written by O. Pironneau and published by Cambridge University Press. This book was released on 1992-07-31 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: The workshop concentrated on the following turbulence test cases: T1 Boundary layer in an S-shaped duct; T2 Periodic array of cylinders in a channel; T3 Transition in a boundary layer under the influence of free-stream turbulence; T4 & T5: Axisymmetric confined jet flows.

Applied mechanics reviews

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ISBN 13 :
Total Pages : 400 pages
Book Rating : 4.3/5 (243 download)

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Book Synopsis Applied mechanics reviews by :

Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Direct Numerical Simulation of Two-phase Flow with Application to Air Layer Drag Reduction

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (743 download)

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Book Synopsis Direct Numerical Simulation of Two-phase Flow with Application to Air Layer Drag Reduction by : Dokyun Kim

Download or read book Direct Numerical Simulation of Two-phase Flow with Application to Air Layer Drag Reduction written by Dokyun Kim and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An accurate and robust numerical method has been developed to simulate turbulent two-phase flows. The phase interface is tracked by the level-set method to capture frequent topological changes due to breaking or merging. Because of the broad-band characteristics of length scales in two-phase flow, a Lagrangian drop breakup model has been developed, which is coupled to the level-set method. In this approach, small subgrid droplets produced from resolved ligaments are then transferred from the level-set representation to the Lagrangian particles. The further secondary atomization is handled by a stochastic breakup model. When pinching-off of ligaments is not resolved on the level-set grid, a capillary breakup model is used to predict the drop size distribution from the pinching off and inserted as Lagrangian drops. This method improves the mass conservation as well as reducing the computational cost. For a high-fidelity simulation of two-phase flow, a new numerical algorithm has been developed to improve the robustness of the numerical method. The conservative formulation of Navier-Stokes equations is solved with a density correction term in the present method. The density flux terms are calculated from the level-set field for accuracy. In addition, a constant coefficient Poisson system is solved for pressure to satisfy the continuity equation in the fractional-step method. In order to show the capability of the method as an efficient tool in the breakup process, the atomization of a round liquid jet surrounded by a coaxial gas is considered. The numerical results are consistent with the observed breakup mechanisms in the experiment and the stability analysis. The drop size distribution of the resulting spray after breakup is also compared with the experimental data. The subgrid drops are also predicted by the Lagrangian drop breakup model, which shows the applicability of our method for numerical simulation of the atomization process. Both theoretical and numerical approaches are employed to investigate the stability mechanisms of the air layer drag reduction (ALDR) phenomenon. A linear viscous stability analysis is performed by solving the Orr-Sommerfeld equations in a two-dimensional two-phase Couette-Poiseuille flow configuration that mimics the far-downstream region from an air injector. Air-layer stability is reduced as the free-stream velocity, Froude number, and velocity gradients at the air-liquid interface are increased, whereas the air-layer stability is enhanced as the gas flow rate and surface tension force are increased. Nonlinear stability characteristics are also studied using numerical simulations with the same Couette flow configuration as indicated in the linear stability analysis. The study shows that the Weber number has a significant effect on the breakup of the phase interface. As the Weber number increases, the liquid ligaments become thinner, requiring higher grid resolution. Therefore, for simulations of high Weber number flows, the use of a Lagrangian spray breakup model is essential to predict the dynamics of subgrid-scale liquid structures. Direct Numerical Simulation (DNS) of two-phase flow is also performed to investigate the air layer drag reduction (ALDR) phenomenon in turbulent water flow over a backward-facing step. The Reynolds and Weber numbers based on the water properties and step height are 22,800 and 560, respectively. The total number of grid points is about 271 million for DNS. Two different air-flow injection rates are examined to investigate the mechanism and stability of the air layer. For high air-flow rate, the stable air layer is formed on the plate and more than 90% drag reduction is obtained, whereas, in the case of low air-flow rate, the air layer breaks up and ALDR is not achieved. The initial Kelvin-Helmholtz instability causes the streamwise wave structure, while turbulence interaction forms the spawise waves and causes ligament breakups. However, overall rupture of the air layer is mainly determined by the stability of the streamwise wave. The stability of the streamwise wave can be predicted from the stability analysis in the far-downstream region.

Direct Numerical Simulation of Laminar and Turbulent Flow in a Channel with Complex, Time-dependent Wall Geometries

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ISBN 13 :
Total Pages : 518 pages
Book Rating : 4.E/5 ( download)

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Book Synopsis Direct Numerical Simulation of Laminar and Turbulent Flow in a Channel with Complex, Time-dependent Wall Geometries by : Henry Andrew Carlson

Download or read book Direct Numerical Simulation of Laminar and Turbulent Flow in a Channel with Complex, Time-dependent Wall Geometries written by Henry Andrew Carlson and published by . This book was released on 1995 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Direct Numerical Simulation of Free-surface and Interfacial Flow Using the VOF Method

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (12 download)

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Book Synopsis Direct Numerical Simulation of Free-surface and Interfacial Flow Using the VOF Method by : Leon Malan

Download or read book Direct Numerical Simulation of Free-surface and Interfacial Flow Using the VOF Method written by Leon Malan and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct numerical simulation of two-phase ow is used extensively for engineering research and fundamental fluid physics studies [54, 81]. This study is based on the Volume-Of-Fluid (VOF) method, originally created by Hirt and Nicols [30]. This method has gained increased popularity, especially when geometric advection techniques are used coupled with a planar reconstruction of the interface [14, 89]. The focus of the first part of this work is to investigate the hydrodynamics of isothermal cavitation in large bubble clouds, which originated from a larger study of micro-spalling [61], conducted by the French CEA. A method to deal with volume-changing vapour cavities, or pores, was formulated and implemented in an existing code, PARIS . The ow is idealized by assuming an inviscid liquid, negligible thermal effects and vanishing vapour pressure. A novel investigation of bubble cloud interaction in an expanding liquid using direct or detailed numerical simulation is presented. The simulation results reveal a pore competition, which is characterised by the Weber number in the ow. In the second part of the study the governing equations are extended to describe incompressible ow with phase change [79]. The description of the work commences with the derivation of the governing equations. Following this, a novel, geometric based, VOF solution method is proposed. In this method a novel way of advecting the VOF function is invented, which treats both mass and energy conservation in conservative form. New techniques include the advection of the interface in a discontinuous velocity field. The proposed algorithms are consistent and elegant, requiring minimal modifications to the existing code. Numerical experiments demonstrate accuracy, robustness and generality. This is viewed as a significant fundamental development in the use of VOF methods to model phase change.

Advances in Numerical Heat Transfer, Volume 2

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Publisher : Routledge
ISBN 13 : 1351468251
Total Pages : 245 pages
Book Rating : 4.3/5 (514 download)

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Book Synopsis Advances in Numerical Heat Transfer, Volume 2 by : W. Minkowycz

Download or read book Advances in Numerical Heat Transfer, Volume 2 written by W. Minkowycz and published by Routledge. This book was released on 2018-12-13 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume discusses the advances in numerical heat transfer modeling by applying high-performance computing resources, striking a balance between generic fundamentals, specific fundamentals, generic applications, and specific applications.

Numerical Study on Liquid-vapor Phase Change with Applications in Vapor Bubble Dynamics

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ISBN 13 :
Total Pages : 158 pages
Book Rating : 4.:/5 (126 download)

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Book Synopsis Numerical Study on Liquid-vapor Phase Change with Applications in Vapor Bubble Dynamics by : Raunak Bardia

Download or read book Numerical Study on Liquid-vapor Phase Change with Applications in Vapor Bubble Dynamics written by Raunak Bardia and published by . This book was released on 2020 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a detailed analysis of vapor bubble dynamics and the interfacial process of liquid-vapor phase change. A spherically symmetric model for a single vapor bubble is employed to present a numerical and theoretical analysis of the intermediate bubble collapse, where, in contrast to the thermally induced or inertia dominated collapse, both the effects of liquid-vapor interfacial heat transfer and the advection of the surrounding liquid play an important role. The contrast in thermal, intermediate, and inertial behavior of collapse is represented in the form of a regime map defined by two non-dimensional quantities, Bsat and Îl, which can be directly evaluated from the initial system conditions of collapse. The same model is also used to simulate a spherically symmetric bubble growth configuration to assess the physical validity of a constant interface temperature assumption made by Highly-Resolved Simulation (HRS) studies aimed at solving flows undergoing phase change. Results show that HRS predictions are inaccurate during the initial period of bubble growth, which coincides with the inertial growth stage. A closed-form expression for a threshold time is derived, beyond which the commonly employed HRS assumptions hold. Forgoing the limitation of spherical symmetry, the second theme of this thesis is on the development of a general two-phase flow solver that can handle the phase change process. Under a finite volume framework using a geometric Volume of Fluid (gVoF) approach, two key challenges with phase change flows have been addressed in this work, namely, (i) added deformation of the interface, and (ii) capture of velocity and pressure gradient discontinuity at the interface, both caused due to phase change. To track the interface in the gVoF scheme, an effective flux is defined that captures the effect of phase change on interface motion. This method improves upon the source term approach used in other studies. For the solution of velocity and pressure, a ghost fluid approach has been implemented, which is the first of its kind in a VoF-based phase change solver.

Scientific and Technical Aerospace Reports

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ISBN 13 :
Total Pages : 892 pages
Book Rating : 4.:/5 (31 download)

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Book Synopsis Scientific and Technical Aerospace Reports by :

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Numerical Methods in Laminar and Turbulent Flow

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Publisher :
ISBN 13 : 9780906674888
Total Pages : 1160 pages
Book Rating : 4.6/5 (748 download)

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Book Synopsis Numerical Methods in Laminar and Turbulent Flow by : Cedric Taylor

Download or read book Numerical Methods in Laminar and Turbulent Flow written by Cedric Taylor and published by . This book was released on 1997 with total page 1160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Numerical Simulation of Turbulent Flows and Noise Generation

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Publisher : Springer
ISBN 13 : 9783642100673
Total Pages : 0 pages
Book Rating : 4.1/5 (6 download)

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Book Synopsis Numerical Simulation of Turbulent Flows and Noise Generation by : Christophe Brun

Download or read book Numerical Simulation of Turbulent Flows and Noise Generation written by Christophe Brun and published by Springer. This book was released on 2010-10-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Eddy Simulation (LES) is a high-fidelity approach to the numerical simulation of turbulent flows. Recent developments have shown LES to be able to predict aerodynamic noise generation and propagation as well as the turbulent flow, by means of either a hybrid or a direct approach. This book is based on the results of two French/German research groups working on LES simulations in complex geometries and noise generation in turbulent flows. The results provide insights into modern prediction approaches for turbulent flows and noise generation mechanisms as well as their use for novel noise reduction concepts.

Modeling and Simulation of Turbulent Multiphase Flows

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ISBN 13 :
Total Pages : 380 pages
Book Rating : 4.3/5 (129 download)

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Book Synopsis Modeling and Simulation of Turbulent Multiphase Flows by : Zhaorui Li

Download or read book Modeling and Simulation of Turbulent Multiphase Flows written by Zhaorui Li and published by . This book was released on 2008 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

New Algorithms for the Direct Numerical Simulation of Turbulent Flows Past Compliant Bodies and the Optimization of Highly Constrained PDE Systems

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ISBN 13 :
Total Pages : 88 pages
Book Rating : 4.:/5 (26 download)

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Book Synopsis New Algorithms for the Direct Numerical Simulation of Turbulent Flows Past Compliant Bodies and the Optimization of Highly Constrained PDE Systems by : Anish Avinash Karandikar

Download or read book New Algorithms for the Direct Numerical Simulation of Turbulent Flows Past Compliant Bodies and the Optimization of Highly Constrained PDE Systems written by Anish Avinash Karandikar and published by . This book was released on 2008 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work develops an efficient and accurate new method for direct numerical simulation of laminar and turbulent flow past a circular cylinder with a deformable (compliant) surface. It studies the interaction of the incompressible flow with the compliant cylinder. From the outset, this is defined as an optimization problem, in which we seek to minimize aeroacoustic noise generated by dipole sound sources on the compliant surface at low Mach numbers. We build on a unique method developed in our lab for simulating turbulent flow in a channel with compliant walls. This method is accurate and efficient for large surface deformations. We adapt this method for the cylindrical polar coordinate system to study flow past a compliant cylinder. In this method, a time-dependent coordinate transformation is used to map the deformed flow domain to a regular computational domain. The governing Navier Stokes equations are formulated in the cylindrical polar form and not the contravariant form, as the latter is computationally expensive to simulate. The compliant surface is modeled by a simple spring-mass-damper system. As surface compliance is increased, a decrease in the peak lift coefficient for the compliant cylinder is observed both in the laminar 2D case at Re = 80, as well as the turbulent 3D case at Re = 300. On the other hand, the frequency of vortex shedding and the time-average drag both increase with surface compliance. This work also develops a new method for optimizing highly-constrained PDE systems by splitting up the governing equations into parallel linear programs, thus achieving scalability. It explores optimization of a single-phase fluid heat exchanger to minimize the power required to drive coolant through it by appropriately adjusting the channel width or channel porosity. The Stokes flow in the heat exchanger is modeled as a resistor network, while the flow rate and pressures in the flow are analogous to currents and voltages in the resistor network. The method developed and demonstrated on the resistor network problem extends naturally to the optimization of the variable channel width/porosity distribution in the heat exchanger model.

Computational Methods for Turbulent, Transonic, and Viscous Flows

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ISBN 13 :
Total Pages : 376 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Computational Methods for Turbulent, Transonic, and Viscous Flows by : Jean-André Essers

Download or read book Computational Methods for Turbulent, Transonic, and Viscous Flows written by Jean-André Essers and published by . This book was released on 1983 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Advances in Computation, Modeling and Control of Transitional and Turbulent Flows

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Publisher : World Scientific
ISBN 13 : 9814635162
Total Pages : 551 pages
Book Rating : 4.8/5 (146 download)

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Book Synopsis Advances in Computation, Modeling and Control of Transitional and Turbulent Flows by : Tapan Kumar Sengupta

Download or read book Advances in Computation, Modeling and Control of Transitional and Turbulent Flows written by Tapan Kumar Sengupta and published by World Scientific. This book was released on 2015-12-01 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The role of high performance computing in current research on transitional and turbulent flows is undoubtedly very important. This review volume provides a good platform for leading experts and researchers in various fields of fluid mechanics dealing with transitional and turbulent flows to synergistically exchange ideas and present the state of the art in the fields. Contributed by eminent researchers, the book chapters feature keynote lectures, panel discussions and the best invited contributed papers."--

Advanced Turbulent Flow Computations

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Publisher : Springer
ISBN 13 : 3709125901
Total Pages : 320 pages
Book Rating : 4.7/5 (91 download)

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Book Synopsis Advanced Turbulent Flow Computations by : Roger Peyret

Download or read book Advanced Turbulent Flow Computations written by Roger Peyret and published by Springer. This book was released on 2014-05-04 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects the lecture notes concerning the IUTAM School on Advanced Turbulent Flow Computations held at CISM in Udine September 7–11, 1998. The course was intended for scientists, engineers and post-graduate students interested in the application of advanced numerical techniques for simulating turbulent flows. The topic comprises two closely connected main subjects: modelling and computation, mesh pionts necessary to simulate complex turbulent flow.

The Interaction of Two-dimensional, Stratified, Turbulent Air-water and Steam-water Flows

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ISBN 13 :
Total Pages : 390 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis The Interaction of Two-dimensional, Stratified, Turbulent Air-water and Steam-water Flows by : John Henry Linehan

Download or read book The Interaction of Two-dimensional, Stratified, Turbulent Air-water and Steam-water Flows written by John Henry Linehan and published by . This book was released on 1968 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: