Download or read book Numerical Modelling and Simulation of Cavitating Marine Propeller Flows written by Maria Gaschler and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-dimensional inviscid boundary element method for the simulation of steady and unsteady partial sheet cavitation on marine propellers is developed. The numerical method is validated in several test cases and applied to the calculation of hydrodynamic loads generated by the flow field around and behind a cavitating propeller on the surrounding structures in the port area.
Download or read book Ship Resistance and Propulsion written by Anthony F. Molland and published by Cambridge University Press. This book was released on 2011-08-08 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts in the ship design field, this book provides a comprehensive approach to evaluating ship resistance and propulsion.
Download or read book Numerical Simulation of Cavitating Bubble laden Turbulent Flows written by Ehsan Shams Sobhani and published by . This book was released on 2010 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many engineering devices and propulsion systems suffer from undesirable effects of cavitation; such as degradation in the efficiency of pumps and turbines, generation of noise and vibration on ship propeller, increased drag and erosion of propeller blade, etc. In spite of decades of research on this problem, detailed study of cavitation physics is still a technical challenge for the current experimental and numerical approaches. Further development of robust and accurate numerical methods for cavitating flow simulation, is the basis of this research. The main objective of this research is to investigate traveling bubble cavitation in turbulent flows. Variable density Navier-Stokes equations are solved in an unstructured grid finite volume solver. Large Eddy Simulation technique with dynamic Smagorinsky subgrid model is used for turbulence modeling. Bubble cavitation is modeled in a Lagrangian framework with subgrid models for forces acting on bubbles. Bubble size variation is modeled using local flow field hydrodynamic pressure for solving Rayliegh-Plesset equation. An adaptive time stepping method is devised for the efficient solution of this highly non-linear equation. Turbulent flow over an open cavity is reproduced numerically from the experimental work by [Liu and Katz, PoF, 08]. Flow statistics agreed very well to those of experiment. Cavitation inception was studied using two different models: (i) discrete bubble model, and (ii) scalar transport model. Severe cavitation was predicted near on top of the trailing edge for cavitation index of [delta]
Download or read book Fundamentals of Cavitation written by Jean-Pierre Franc and published by Springer Science & Business Media. This book was released on 2006-01-22 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book treats cavitation, which is a unique phenomenon in the field of hyd- dynamics, although it can occur in any hydraulic machinery such as pumps, propellers, artificial hearts, and so forth. Cavitation is generated not only in water, but also in any kind of fluid, such as liquid hydrogen. The generation of cavitation can cause severe damage in hydraulic machinery. Therefore, the prevention of cavitation is an important concern for designers of hydraulic machinery. On the contrary, there is great potential to utilize cavitation in various important applications, such as environmental protection. There have been several books published on cavitation, including one by the same authors. This book differs from those previous ones, in that it is both more physical and more theoretical. Any theoretical explanation of the cavitation phenomenon is rather difficult, but the authors have succeeded in explaining it very well, and a reader can follow the equations easily. It is an advantage in reading this book to have some understanding of the physics of cavitation. Therefore, this book is not an introductory text, but a book for more advanced study. However, this does not mean that this book is too difficult for a beginner, because it explains the cavitation phenomenon using many figures. Therefore, even a beginner on cavitation can read and can understand what cavitation is. If the student studies through this book (with patience), he or she can become an expert on the physics of cavitation.
Download or read book Computational Fluid Dynamics written by Jiri Blazek and published by Elsevier. This book was released on 2005-12-20 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid Dynamics (CFD) is an important design tool in engineering and also a substantial research tool in various physical sciences as well as in biology. The objective of this book is to provide university students with a solid foundation for understanding the numerical methods employed in today's CFD and to familiarise them with modern CFD codes by hands-on experience. It is also intended for engineers and scientists starting to work in the field of CFD or for those who apply CFD codes. Due to the detailed index, the text can serve as a reference handbook too. Each chapter includes an extensive bibliography, which provides an excellent basis for further studies.
Download or read book Numerical Simulation and Analysis of Shock Phenomena in Cavitating Flow and Its Application to Ship Propellers written by Bernd Budich and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Papers from the Sixth International Symposium on Marine Propulsors written by Sverre Steen and published by MDPI. This book was released on 2020-12-29 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine propulsors are key components of the many thousands of ships and boats operating in oceans, lakes, and rivers around the world. The performance of propulsors are important for the environmental impact of ships, underwater noise impact on aquatic fauna, and crew and passenger comfort and safety. This book presents nineteen papers devoted to the hydrodynamics of different types of marine propulsors (conventional propellers, thrusters, and novel solutions). Most of the papers are extended papers from the sixth International Symposium on Marine Propulsors (SMP 2019). Several of the papers deal with cavitation, vortices, and energy saving devices. The papers present high-quality research performed using Computational Fluid Dynamics (CFD) and Experimental Fluid Dynamics (EFD) as well Artificial Intelligence (AI).
Download or read book Marine Propellers and Propulsion written by John Carlton and published by Butterworth-Heinemann. This book was released on 2012-10-30 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early development of the screw propeller. Propeller geometry. The propeller environment. The ship wake field, propeller performance characteristics.
Download or read book Marine Propulsors written by Sverre Steen and published by MDPI. This book was released on 2018-10-10 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Marine Propulsors" that was published in JMSE
Download or read book Numerical Modeling of Natural and Ventilated Cavitating Flows written by Qiao Qin and published by . This book was released on 2004 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Modeling of a Hydrofoil Or a Marine Propeller Undergoing Unsteady Motion Via a Panel Method and RANS written by Abhinav Sharma (master of science in civil engineering.) and published by . This book was released on 2011 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational approach to analyze the hydrodynamic performance of a hydrofoil or a marine propeller undergoing unsteady motion has been developed. In order to simulate heave and pitch motion of a hydrofoil, an unsteady boundary element method based modeling is performed. The wake of the hydrofoil is modeled by a continuous dipole sheet and determined in time by applying a force-free condition on its surface. An explicit vortex core model is adapted in this model to capture the rolling up shape and to avoid instability due to roll-up deformation of the wake. The numerical results of the developed model are compared with analytical results and those from the commercial Reynolds-Averaged Navier-Stokes solver (ANSYS/FLUENT). The results show close level of agreement with each other. The problem of flow around a marine propeller performing surge, roll and heave motion in an unbounded fluid is formulated and solved using both a vortex-lattice method and a boundary element method. A fully unsteady wake alignment algorithm is implemented into the vortex-lattice method in order to satisfy the force-free condition on the propeller wake surface. Finally, a comparative study of transient propeller forces on a propeller blade obtained from BEM and VLM (with or without fully aligned wake) is carried out and results are presented. In some cases, results from the presented methods are compared with those from RANS or other numerical methods available in the literature.
Download or read book A Numerical Study of Cavitating Flows Based on Plic vof Method for Arbitrary Unstructured Meshes written by Dezhi Dai and published by . This book was released on 2022 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cavitation appears when local static pressure drops below the water vapor pressure and causes significant impacts on marine propeller blades. The Volume of Fluid (VOF) method, which is also referred to as the Transport Equation-based Model (TEM), has been extensively adopted in the cavitating flow simulations. Piecewise Linear Interface Calculation (PLIC) schemes have been extensively employed in the VOF method for interface capturing in numerical simulations of multiphase flows. Polyhedral unstructured meshes are often adopted due to their geometric flexibility and superiority in gradient calculation. Four analytical interface reconstruction algorithms in the PLIC-VOF method for arbitrary convex polyhedral cells have been proposed in the present study. The plane interface at a given orientation within a polyhedral cell is located by four different analytical techniques. They have been tested successfully for six different geometric shapes that are common in polyhedral meshes. The computational efficiencies of the algorithms have been compared with two other published schemes in the literature. The proposed algorithms have been shown to yield smaller truncation errors with a reduction in computational complexity. A numerical simulation of a 3D dam-breaking problem has been successfully performed using the proposed interface reconstruction scheme on a polyhedral mesh. The percentage of the overall computational time consumed has been assessed to justify its optimization in a real multiphase flow simulation. The effects of cavitation on the dynamics of a two-dimensional hydrofoil and three-dimensional propeller have been studied numerically. Analytical PLIC-VOF methods on overset unstructured meshes have been employed to capture the interface between liquid and vapor phases in cavitating flows around a NACA 66 (MOD) hydrofoil and PPTC propeller. A modified version of the Schnerr-Sauer cavitation model has been adopted to compute the local mass transport rate for the vaporization and condensation processes. Turbulent eddy viscosity is evaluated by using the Spalart-Allmaras one-equation model. Simulations are performed under the framework of OpenFOAM with a modified flow solver. Stable sheet and unstable cloud cavitations have been investigated. The findings in the present study are consistent with experimental studies reported in the literature.
Download or read book Mechanics of Underwater Noise written by Donald Ross and published by Elsevier. This book was released on 2013-10-22 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipole) sources, and mechanical noise sources. This book will be helpful as a self-education text and as a reference for workers in the field.
Download or read book Twenty First Symposium on Naval Hydrodynamics written by National Research Council and published by National Academies Press. This book was released on 1997-09-11 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Twenty Second Symposium on Naval Hydrodynamics written by National Research Council and published by National Academies Press. This book was released on 2000-03-02 with total page 1039 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Twenty-Second Symposium on Naval Hydrodynamics was held in Washington, D.C., from August 9-14, 1998. It coincided with the 100th anniversary of the David Taylor Model Basin. This international symposium was organized jointly by the Office of Naval Research (Mechanics and Energy Conversion S&T Division), the National Research Council (Naval Studies Board), and the Naval Surface Warfare Center, Carderock Division (David Taylor Model Basin). This biennial symposium promotes the technical exchange of naval research developments of common interest to all the countries of the world. The forum encourages both formal and informal discussion of the presented papers, and the occasion provides an opportunity for direct communication between international peers.
Download or read book MARINE 2011 IV International Conference on Computational Methods in Marine Engineering written by Luís Eça and published by Springer Science & Business Media. This book was released on 2013-03-19 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains selected papers from the Fourth International Conference on Computational Methods in Marine Engineering, held at Instituto Superior Técnico, Technical University of Lisbon, Portugal in September 2011. Nowadays, computational methods are an essential tool of engineering, which includes a major field of interest in marine applications, such as the maritime and offshore industries and engineering challenges related to the marine environment and renewable energies. The 2011 Conference included 8 invited plenary lectures and 86 presentations distributed through 10 thematic sessions that covered many of the most relevant topics of marine engineering today. This book contains 16 selected papers from the Conference that cover “CFD for Offshore Applications”, “Fluid-Structure Interaction”, “Isogeometric Methods for Marine Engineering”, “Marine/Offshore Renewable Energy”, “Maneuvering and Seakeeping”, “Propulsion and Cavitation” and “Ship Hydrodynamics”. The papers were selected with the help of the recognized experts that collaborated in the organization of the thematic sessions of the Conference, which guarantees the high quality of the papers included in this book.
Download or read book Cavitation and Bubble Dynamics written by Phoevos Koukouvinis and published by Elsevier. This book was released on 2021-09-24 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cavitation and Bubble Dynamics: Fundamentals and Applications examines the latest advances in the field of cavitation and multiphase flows, including associated effects such as material erosion and spray instabilities. This book tackles the challenges of cavitation hindrance in the industrial world, while also drawing on interdisciplinary research to inform academic audiences on the latest advances in the fundamentals. Contributions to the book come from a wide range of specialists in areas including fuel systems, hydropower, marine engineering, multiphase flows and computational fluid mechanics, allowing readers to discover novel interdisciplinary experimentation techniques and research results. This book will be an essential tool for industry professionals and researchers working on applications where cavitation hindrance affects reliability, noise, and vibrations. - Covers a wide range of cavitation and bubble dynamics phenomena, including shock wave emission, jetting, and luminescence - Provides the latest advice about applications including cavitation tunnels, cavitation testing, flow designs to avoid cavitation in pumps and other hydromachinery, and flow lines - Describes novel experimental techniques, such as x-ray imaging and new computational techniques
