The Height Limit of a Siphon
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The Role of MHD Turbulence in Magnetic Self-Excitation in The
THE ROLE OF MHD TURBULENCE IN MAGNETIC SELF-EXCITATION: A STUDY OF THE MADISON DYNAMO EXPERIMENT by Mark D. Nornberg A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Physics) at the UNIVERSITY OF WISCONSIN–MADISON 2006 °c Copyright by Mark D. Nornberg 2006 All Rights Reserved i For my parents who supported me throughout college and for my wife who supported me throughout graduate school. The rest of my life I dedicate to my daughter Margaret. ii ACKNOWLEDGMENTS I would like to thank my adviser Cary Forest for his guidance and support in the completion of this dissertation. His high expectations and persistence helped drive the work presented in this thesis. I am indebted to him for the many opportunities he provided me to connect with the world-wide dynamo community. I would also like to thank Roch Kendrick for leading the design, construction, and operation of the experiment. He taught me how to do science using nothing but duct tape, Sharpies, and Scotch-Brite. He also raised my appreciation for the artistry of engineer- ing. My thanks also go to the many undergraduate students who assisted in the construction of the experiment, especially Craig Jacobson who performed graduate-level work. My research partner, Erik Spence, deserves particular thanks for his tireless efforts in modeling the experiment. His persnickety emendations were especially appreciated as we entered the publi- cation stage of the experiment. The conversations during our morning commute to the lab will be sorely missed. I never imagined forging such a strong friendship with a colleague, and I hope our families remain close despite great distance. -
Chapter 5 Dimensional Analysis and Similarity
Chapter 5 Dimensional Analysis and Similarity Motivation. In this chapter we discuss the planning, presentation, and interpretation of experimental data. We shall try to convince you that such data are best presented in dimensionless form. Experiments which might result in tables of output, or even mul- tiple volumes of tables, might be reduced to a single set of curves—or even a single curve—when suitably nondimensionalized. The technique for doing this is dimensional analysis. Chapter 3 presented gross control-volume balances of mass, momentum, and en- ergy which led to estimates of global parameters: mass flow, force, torque, total heat transfer. Chapter 4 presented infinitesimal balances which led to the basic partial dif- ferential equations of fluid flow and some particular solutions. These two chapters cov- ered analytical techniques, which are limited to fairly simple geometries and well- defined boundary conditions. Probably one-third of fluid-flow problems can be attacked in this analytical or theoretical manner. The other two-thirds of all fluid problems are too complex, both geometrically and physically, to be solved analytically. They must be tested by experiment. Their behav- ior is reported as experimental data. Such data are much more useful if they are ex- pressed in compact, economic form. Graphs are especially useful, since tabulated data cannot be absorbed, nor can the trends and rates of change be observed, by most en- gineering eyes. These are the motivations for dimensional analysis. The technique is traditional in fluid mechanics and is useful in all engineering and physical sciences, with notable uses also seen in the biological and social sciences. -
Cavitation in Valves
VM‐CAV/WP White Paper Cavitation in Valves Table of Contents Introduction. 2 Cavitation Analysis. 2 Cavitation Data. 3 Valve Coefficient Data. 4 Example Application. .. 5 Conclusion & Recommendations . 5 References. 6 Val‐Matic Valve & Mfg. Corp. • www.valmatic.com • [email protected] • PH: 630‐941‐7600 Copyright © 2018 Val‐Matic Valve & Mfg. Corp. Cavitation in Valves INTRODUCTION Cavitation can occur in valves when used in throttling or modulating service. Cavitation is the sudden vaporization and violent condensation of a liquid downstream of the valve due to localized low pressure zones. When flow passes through a throttled valve, a localized low pressure zone forms immediately downstream of the valve. If the localized pressure falls below the vapor pressure of the fluid, the liquid vaporizes (boils) and forms a vapor pocket. As the vapor bubbles flow downstream, the pressure recovers, and the bubbles violently implode causing a popping or rumbling sound similar to tumbling rocks in a pipe. The sound of cavitation in a pipeline is unmistakable. The condensation of the bubbles not only produces a ringing sound, but also creates localized stresses in the pipe walls and valve body that can cause severe pitting. FIGURE 1. Cavitation Cavitation is a common occurrence in shutoff valves during the last few degrees of closure when the supply pressure is greater than about 100 psig. Valves can withstand limited durations of cavitation, but when the valve must be throttled or modulated in cavitating conditions for long periods of time, the life of the valve can be drastically reduced. Therefore, an analysis of flow conditions is needed when a valve is used for flow or pressure control. -
Control Valve Sizing Theory, Cavitation, Flashing Noise, Flashing and Cavitation Valve Pressure Recovery Factor
Control Valve Sizing Theory, Cavitation, Flashing Noise, Flashing and Cavitation Valve Pressure Recovery Factor When a fluid passes through the valve orifice there is a marked increase in velocity. Velocity reaches a maximum and pressure a minimum at the smallest sectional flow area just downstream of the orifice opening. This point of maximum velocity is called the Vena Contracta. Downstream of the Vena Contracta the fluid velocity decelerates and the pressure increases of recovers. The more stream lined valve body designs like butterfly and ball valves exhibit a high degree of pressure recovery where as Globe style valves exhibit a lower degree of pressure recovery because of the Globe geometry the velocity is lower through the vena Contracta. The Valve Pressure Recovery Factor is used to quantify this maximum velocity at the vena Contracta and is derived by testing and published by control valve manufacturers. The Higher the Valve Pressure Recovery Factor number the lower the downstream recovery, so globe style valves have high recovery factors. ISA uses FL to represent the Valve Recovery Factor is valve sizing equations. Flow Through a restriction • As fluid flows through a restriction, the Restriction Vena Contracta fluid’s velocity increases. Flow • The Bernoulli Principle P1 P2 states that as the velocity of a fluid or gas increases, its pressure decreases. Velocity Profile • The Vena Contracta is the point of smallest flow area, highest velocity, and Pressure Profile lowest pressure. Terminology Vapor Pressure Pv The vapor pressure of a fluid is the pressure at which the fluid is in thermodynamic equilibrium with its condensed state. -
Eulerian–Lagrangian Method for Simulation of Cloud Cavitation ∗ Kazuki Maeda , Tim Colonius
Journal of Computational Physics 371 (2018) 994–1017 Contents lists available at ScienceDirect Journal of Computational Physics www.elsevier.com/locate/jcp Eulerian–Lagrangian method for simulation of cloud cavitation ∗ Kazuki Maeda , Tim Colonius Division of Engineering and Applied Science, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA a r t i c l e i n f o a b s t r a c t Article history: We present a coupled Eulerian–Lagrangian method to simulate cloud cavitation in a Received 3 December 2017 compressible liquid. The method is designed to capture the strong, volumetric oscillations Received in revised form 10 April 2018 of each bubble and the bubble-scattered acoustics. The dynamics of the bubbly mixture Accepted 16 May 2018 is formulated using volume-averaged equations of motion. The continuous phase is Available online 18 May 2018 discretized on an Eulerian grid and integrated using a high-order, finite-volume weighted Keywords: essentially non-oscillatory (WENO) scheme, while the gas phase is modeled as spherical, Bubble dynamics Lagrangian point-bubbles at the sub-grid scale, each of whose radial evolution is tracked Cavitation by solving the Keller–Miksis equation. The volume of bubbles is mapped onto the Eulerian Eulerian–Lagrangian method grid as the void fraction by using a regularization (smearing) kernel. In the most general Compressible multiphase flows case, where the bubble distribution is arbitrary, three-dimensional Cartesian grids are used Multiscale modeling for spatial discretization. In order to reduce the computational cost for problems possessing Reduced-order modeling translational or rotational homogeneities, we spatially average the governing equations along the direction of symmetry and discretize the continuous phase on two-dimensional or axi-symmetric grids, respectively. -
Hydraulics Manual Glossary G - 3
Glossary G - 1 GLOSSARY OF HIGHWAY-RELATED DRAINAGE TERMS (Reprinted from the 1999 edition of the American Association of State Highway and Transportation Officials Model Drainage Manual) G.1 Introduction This Glossary is divided into three parts: · Introduction, · Glossary, and · References. It is not intended that all the terms in this Glossary be rigorously accurate or complete. Realistically, this is impossible. Depending on the circumstance, a particular term may have several meanings; this can never change. The primary purpose of this Glossary is to define the terms found in the Highway Drainage Guidelines and Model Drainage Manual in a manner that makes them easier to interpret and understand. A lesser purpose is to provide a compendium of terms that will be useful for both the novice as well as the more experienced hydraulics engineer. This Glossary may also help those who are unfamiliar with highway drainage design to become more understanding and appreciative of this complex science as well as facilitate communication between the highway hydraulics engineer and others. Where readily available, the source of a definition has been referenced. For clarity or format purposes, cited definitions may have some additional verbiage contained in double brackets [ ]. Conversely, three “dots” (...) are used to indicate where some parts of a cited definition were eliminated. Also, as might be expected, different sources were found to use different hyphenation and terminology practices for the same words. Insignificant changes in this regard were made to some cited references and elsewhere to gain uniformity for the terms contained in this Glossary: as an example, “groundwater” vice “ground-water” or “ground water,” and “cross section area” vice “cross-sectional area.” Cited definitions were taken primarily from two sources: W.B. -
Frequently Asked Questions
FREQUENTLY ASKED QUESTIONS Pressure Washer Chemicals/Cleaners Q: Can I use chemicals that do not state pressure washer safe? Can I use bleach in my pressure washer? A: It is recommended that only cleaning products that state "pressure washer safe" be used. Please ensure to follow all of the manufacturer's instructions. Using bleach or any other chemicals/cleaners that do not state "pressure washer safe" can cause premature wear and damage to seals and o-rings. Continuous Water Source Requirement for Pressure Washers Q: Does my pressure washer require a continuous water source? A: Pressure washers require a continuous pressurized water source. If there is not adequate water to the pump, the unit will not operate correctly and the pump may sustain damage. Please check your Operator's Manual for the specific requirements of gallons per minute and psi for your unit. Pressure Washer Siphon Troubleshooting Q: How do I get the pressure washer to siphon? A: For basic operating instructions related to your specific pressure washer, please refer to your product Owner's Manual. Possible causes for lack of siphoning include: • Chemical hose placed on improper port -- Check clear hose placement. • Pressure washer is not set to low pressure --The unit must be set to low pressure to apply soap. Please be sure that the correct soap nozzle is being used. • Extension is being used on the high pressure hose -- Remove extension on high pressure hose. • Chemical injection area is clogged or component needs to be replaced -- Test for blockage: Remove nozzle extension from gun, attach and turn on water source, then pull the trigger. -
PLUMBING DICTIONARY Sixth Edition
as to produce smooth threads. 2. An oil or oily preparation used as a cutting fluid espe cially a water-soluble oil (such as a mineral oil containing- a fatty oil) Cut Grooving (cut groov-ing) the process of machining away material, providing a groove into a pipe to allow for a mechani cal coupling to be installed.This process was invented by Victau - lic Corp. in 1925. Cut Grooving is designed for stanard weight- ceives or heavier wall thickness pipe. tetrafluoroethylene (tet-ra-- theseveral lower variouslyterminal, whichshaped re or decalescensecryolite (de-ca-les-cen- ming and flood consisting(cry-o-lite) of sodium-alumi earthfluo-ro-eth-yl-ene) by alternately dam a colorless, thegrooved vapors tools. from 4. anonpressure tool used by se) a decrease in temperaturea mineral nonflammable gas used in mak- metalworkers to shape material thatnum occurs fluoride. while Usedheating for soldermet- ing a stream. See STANK. or the pressure sterilizers, and - spannering heat resistantwrench and(span-ner acid re - conductsto a desired the form vapors. 5. a tooldirectly used al ingthrough copper a rangeand inalloys which when a mixed with phosphoric acid.- wrench)sistant plastics 1. one ofsuch various as teflon. tools to setthe theouter teeth air. of Sometimesaatmosphere circular or exhaust vent. See change in a structure occurs. Also used for soldering alumi forAbbr. tightening, T.F.E. or loosening,chiefly Brit.: orcalled band vapor, saw. steam,6. a tool used to degree of hazard (de-gree stench trap (stench trap) num bronze when mixed with nutsthermal and bolts.expansion 2. (water) straightenLOCAL VENT. -
A Numerical Algorithm for MHD of Free Surface Flows at Low Magnetic Reynolds Numbers
A Numerical Algorithm for MHD of Free Surface Flows at Low Magnetic Reynolds Numbers Roman Samulyak1, Jian Du2, James Glimm1;2, Zhiliang Xu1 1Computational Science Center, Brookhaven National Laboratory, Upton, NY 11973 2 Department of Applied Mathematics and Statistics, SUNY at Stony Brook, Stony Brook, NY 11794, USA November 7, 2005 Abstract We have developed a numerical algorithm and computational soft- ware for the study of magnetohydrodynamics (MHD) of free surface flows at low magnetic Reynolds numbers. The governing system of equations is a coupled hyperbolic/elliptic system in moving and ge- ometrically complex domains. The numerical algorithm employs the method of front tracking for material interfaces, high resolution hy- perbolic solvers, and the embedded boundary method for the elliptic problem in complex domains. The numerical algorithm has been imple- mented as an MHD extension of FronTier, a hydrodynamic code with free interface support. The code is applicable for numerical simulations of free surface conductive liquids or flows of weakly ionized plasmas. Numerical simulations of the Muon Collider/Neutrino Factory target have been discussed. 1 Introduction Computational magnetohydrodynamics, greatly inspired over the last decades by the magnetic confinement fusion and astrophysics problems, has achieved significant results. However the major research effort has been in the area of highly ionized plasmas. Numerical methods and computational software for MHD of weakly conducting materials such as liquid metals or weakly ionized plasmas have not been developed to such an extent despite the need 1 for fusion research and industrial technologies. Liquid metal MHD, driven by potential applications of flowing liquid metals or electrically conducting liquid salts as coolant in magnetic confinement fusion reactors as well as some industrial problems, has attracted broad theoretical, computational, and experimental studies (see [16, 17, 18] and references therein). -
Toward a Self-Generating Magnetic Dynamo: the Role of Turbulence
PHYSICAL REVIEW E VOLUME 61, NUMBER 5 MAY 2000 Toward a self-generating magnetic dynamo: The role of turbulence Nicholas L. Peffley, A. B. Cawthorne, and Daniel P. Lathrop* Department of Physics, University of Maryland, College Park, Maryland 20742 ͑Received 6 July 1999͒ Turbulent flow of liquid sodium is driven toward the transition to self-generating magnetic fields. The approach toward the transition is monitored with decay measurements of pulsed magnetic fields. These mea- surements show significant fluctuations due to the underlying turbulent fluid flow field. This paper presents experimental characterizations of the fluctuations in the decay rates and induced magnetic fields. These fluc- tuations imply that the transition to self-generation, which should occur at larger magnetic Reynolds number, will exhibit intermittent bursts of magnetic fields. PACS number͑s͒: 47.27.Ϫi, 47.65.ϩa, 05.45.Ϫa, 91.25.Cw I. INTRODUCTION Reynolds number will be quite large for all flows attempting to self-generate ͑where Re ӷ1 yields Reӷ105)—implying The generation of magnetic fields from flowing liquid m turbulent flow. These turbulent flows will cause the transition metals is being pursued by a number of scientific research to self-generation to be intermittent, showing both growth groups in Europe and North America. Nuclear engineering and decay of magnetic fields irregularly in space and time. has facilitated the safe use of liquid sodium, which has con- This intermittency is not something addressed by kinematic tributed to this new generation of experiments. With the dynamo studies. The analysis in this paper focuses on three highest electrical conductivity of any liquid, sodium retains main points: we quantify the approach to self-generation and distorts magnetic fields maximally before they diffuse with increasing Rem , characterize the turbulence of induced away. -
Numerical Study of Cavitation Within Orifice Flow
NUMERICAL STUDY OF CAVITATION WITHIN ORIFICE FLOW A Thesis by PENGZE YANG Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Chair of Committee, Robert Handler Committee Members, David Staack Prabir Daripa Head of Department, Andreas Polycarpou December 2015 Major Subject: Mechanical Engineering Copyright 2015 Pengze Yang ABSTRACT Cavitation generally occurs when the pressure at certain location drops to the vapor pressure and the liquid water evaporates as a consequence. For the past several decades, numerous experimental researches have been conducted to investigate this phenomenon due to its degradation effects on hydraulic device structures, such as erosion, noise and vibration. A plate orifice is an important restriction device that is widely used in many industries. It serves functions as restricting flow and measuring flow rate within a pipe. The plate orifice is also subject to intense cavitation at high pressure difference, therefore, the simulation research of the cavitation phenomenon within an orifice flow becomes quite essential for understanding the causes of cavitation and searching for possible preventing methods. In this paper, all researches are simulation-oriented by using ANSYS FLUENT due to its high resolution comparing to experiments. Standard orifice plates based on ASME PTC 19.5-2004 are chosen and modeled in the study with the diameter ratio from 0.2 to 0.75. Steady state studies are conducted for each diameter ratio at the cavitation number roughly from 0.2 to 2.5 to investigate the dependency of discharge coefficient on the cavitation number. -
Glossary of Terms — Page 1 Air Gap: See Backflow Prevention Device
Glossary of Irrigation Terms Version 7/1/17 Edited by Eugene W. Rochester, CID Certification Consultant This document is in continuing development. You are encouraged to submit definitions along with their source to [email protected]. The terms in this glossary are presented in an effort to provide a foundation for common understanding in communications covering irrigation. The following provides additional information: • Items located within brackets, [ ], indicate the IA-preferred abbreviation or acronym for the term specified. • Items located within braces, { }, indicate quantitative IA-preferred units for the term specified. • General definitions of terms not used in mathematical equations are not flagged in any way. • Three dots (…) at the end of a definition indicate that the definition has been truncated. • Terms with strike-through are non-preferred usage. • References are provided for the convenience of the reader and do not infer original reference. Additional soil science terms may be found at www.soils.org/publications/soils-glossary#. A AC {hertz}: Abbreviation for alternating current. AC pipe: Asbestos-cement pipe was commonly used for buried pipelines. It combines strength with light weight and is immune to rust and corrosion. (James, 1988) (No longer made.) acceleration of gravity. See gravity (acceleration due to). acid precipitation: Atmospheric precipitation that is below pH 7 and is often composed of the hydrolyzed by-products from oxidized halogen, nitrogen, and sulfur substances. (Glossary of Soil Science Terms, 2013) acid soil: Soil with a pH value less than 7.0. (Glossary of Soil Science Terms, 2013) adhesion: Forces of attraction between unlike molecules, e.g. water and solid.