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Two-Dimensional Hydrodynamic Modeling of Two-Phase Flow for Understanding Geyser Phenomena in Urban Stormwater System" (2013)

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Two-Dimensional Hydrodynamic Modeling of Two-Phase Flow for Understanding Geyser Phenomena in Urban Stormwater System University of Kentucky UKnowledge Theses and Dissertations--Civil Engineering Civil Engineering 2013 TWO-DIMENSIONAL HYDRODYNAMIC MODELING OF TWO- PHASE FLOW FOR UNDERSTANDING GEYSER PHENOMENA IN URBAN STORMWATER SYSTEM Zhiyu S. Shao University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Shao, Zhiyu S., "TWO-DIMENSIONAL HYDRODYNAMIC MODELING OF TWO-PHASE FLOW FOR UNDERSTANDING GEYSER PHENOMENA IN URBAN STORMWATER SYSTEM" (2013). Theses and Dissertations--Civil Engineering. 5. https://uknowledge.uky.edu/ce_etds/5 This Doctoral Dissertation is brought to you for free and open access by the Civil Engineering at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Civil Engineering by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained and attached hereto needed written permission statements(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine). I hereby grant to The University of Kentucky and its agents the non-exclusive license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless a preapproved embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s dissertation including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Zhiyu S. Shao, Student Dr. Scott A. Yost, Major Professor Dr. Kamyar C. Mahboub, Director of Graduate Studies TWO-DIMENSIONAL HYDRODYNAMIC MODELING OF TWO-PHASE FLOW FOR UNDERSTANDING GEYSER PHENOMENA IN URBAN STORMWATER SYSTEM ________________________________________________________________________ DISSERTATION ________________________________________________________________________ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Engineering at the University of Kentucky By Zhiyu Shannon Shao Lexington, Kentucky Director: Dr. Scott A. Yost, Associate Professor of Civil Engineering Lexington, Kentucky 2013 Copyright © Zhiyu Shannon Shao 2013 ABSTRACT OF DISSERTATION TWO-DIMENSIONAL HYDRODYNAMIC MODELING OF TWO-PHASE FLOW FOR UNDERSTANDING GEYSER PHENOMENA IN URBAN STORMWATER SYSTEM During intense rain events a stormwater system can fill rapidly and undergo a transition from open channel flow to pressurized flow. This transition can create large discrete pockets of trapped air in the system. These pockets are pressurized in the horizontal reaches of the system and then are released through vertical vents. In extreme cases, the transition and release of air pockets can create a geyser feature. The current models are inadequate for simulating mixed flows with complicated air-water interactions, such as geysers. Additionally, the simulation of air escaping in the vertical dropshaft is greatly simplified, or completely ignored, in the existing models. In this work a two-phase numerical model solving the Navier-Stokes equations is developed to investigate the key factors that form geysers. A projection method is used to solve the Navier-Stokes Equation. An advanced two-phase flow model, Volume of Fluid (VOF), is implemented in the Navier-Stokes solver to capture and advance the interface. This model has been validated with standard two-phase flow test problems that involve significant interface topology changes, air entrainment and violent free surface motion. The results demonstrate the capability of handling complicated two-phase interactions. The numerical results are compared with experimental data and theoretical solutions. The comparisons consistently show satisfactory performance of the model. The model is applied to a real stormwater system and accurately simulates the pressurization process in a horizontal channel. The two-phase model is applied to simulate air pockets rising and release motion in a vertical riser. The numerical model demonstrates the dominant factors that contribute to geyser formation, including air pocket size, pressurization of main pipe and surcharged state in the vertical riser. It captures the key dynamics of two-phase flow in the vertical riser, consistent with experimental results, suggesting that the code has an excellent potential of extending its use to practical applications. Key Words: mixed flow, multi-phase flow, Navier-Stokes equation, projection methods, VOF Zhiyu S. Shao Student’s Signature 03/18/2013 Date TWO-DIMENSIONAL HYDRODYNAMIC MODELING OF TWO-PHASE FLOW FOR UNDERSTANDING GEYSER PHENOMENA IN URBAN STORMWATER SYSTEM By Zhiyu Shannon Shao Scott A. Yost Director of Dissertation Kamyar C. Mahboub Director of Graduate Studies 03/18/2013 I would like to dedicate this dissertation to my family, especially… my parents and my son, Ryan Xuanyuan Gong ACKNOWLEDGEMENTS I want to express my sincere gratitude to Dr. Scott A. Yost and Dr. James M. McDonough for providing me with advice, direction and guidance in the course of pursuing this work. The directions I received from them often led to critical thoughts and motivations to further improve my work, and more importantly, correct the mistakes I have made. Dr. Yost has been an excellent academic advisor and mentor in all the years. He had never once given up on me and has been working patiently, teaching and encouraging me in every aspect of my life. Without the encouragement and friendship from Dr. Yost, this PhD work will not be possible. He is without any doubt one of the most influential people in my life. I also thank Dr. Scott F. Bradford for the many discussions about multi-phase flows in this work. The discussions have been very beneficial and helpful. I would also like to acknowledge Dr. Tate Tsang and Dr. Jimmy Fox for their encouragements and advice during the course of this work, and their service on my committee for this dissertation. Furthermore, I would like to thank my family members, especially my parents and my husband for their unconditional love and support. I want to thank our son, Ryan Xuanyuan, my greatest sources of joy and hope. I would like to take this opportunity to thank my friend and colleague Tien Mun Yee for his help, encouragement and friendship. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................................ iii LIST OF TABLES ......................................................................................................................... vii LIST OF FIGURES ...................................................................................................................... viii NOMENCLATURE ....................................................................................................................... xi ABBREVIATIONS ...................................................................................................................... xiii CHAPTER 1 INTRODUCTION ..................................................................................................... 1 1.1. Geyser feature .................................................................................................................. 1 1.2. Existing studies ................................................................................................................ 2 1.2.1. Experimental Study .................................................................................................. 2 1.2.2. Field Study ............................................................................................................... 5 1.2.3. Numerical Study ...................................................................................................... 5 1.3. Motivations ...................................................................................................................... 7 1.4. Physical Scenarios ........................................................................................................... 8 CHAPTER 2 LITERATURE REVIEW ........................................................................................ 10 2.1. Priessmann Slot Method ................................................................................................ 12 2.2. Shock Fitting Method .................................................................................................... 14 2.3. Rigid Column Method ................................................................................................... 16 2.4. Other Numerical Models ...............................................................................................
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