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High Order Long-Time Accurate Methods for the Stokes-Darcy System and Uncertainty PDF

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Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2015 High Order Long-Time Accurate Methods for the Stokes-Darcy System and Uncertainty Quantification of Contaminant Transport Dong Sun Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES HIGH ORDER LONG-TIME ACCURATE METHODS FOR THE STOKES-DARCY SYSTEM AND UNCERTAINTY QUANTIFICATION OF CONTAMINANT TRANSPORT By DONG SUN A Dissertation submitted to the Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2015 Copyright c 2015 Dong Sun. All Rights Reserved. ⃝ Dong Sun defended this dissertation on 5/12/2015. The members of the supervisory committee were: Xiaoming Wang Professor Co-Directing Dissertation Max Gunzburger Professor Co-Directing Dissertation Xiaoqiang Wang University Representative Brian Ewald Committee Member Nick Cogan Committee Member TheGraduateSchoolhasverifiedandapprovedtheabove-namedcommitteemembers, andcertifies that the dissertation has been approved in accordance with university requirements. ii ACKNOWLEDGMENTS First I would like to thank my two major professors, Xiaoming Wang and Max Gunzburger. With- out you two, this dissertation would not be possible and I would not be who I am today. You two alwaysgaveyourwisdomandinsighttohelpguidemethroughmymorethanfive-year-longjourney as a Ph.D. student. Wenbin Chen, a senior collaborator, also helped me a lot in both academic and life experiences. Your enthusiasm about everything is impressive. I also want to thank Xiaoming He who got me started when I first came here. Daozhi Han and Nan Chen are the other two I want to thank for their help. Jin Cheng motivated me to choose this path; thank you too. I also want to thank my family for their ultimate support, especially my grandfather. Thank you all for making me who I am today. iii TABLE OF CONTENTS List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii 1 Introduction 1 2 The Stokes–Darcy system and its weak formulation 5 2.1 Conceptual domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Stokes equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 The Darcy equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.4 The Stokes–Darcy system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.5 Sobolev spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.6 Weak formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.7 Saddle point theory and well-posedness of the steady-state problem . . . . . . . . . . 10 3 Two types of second-order IMplicit-EXplicit (IMEX) methods 13 3.1 The second-order backward-differentiation method (BDF2) . . . . . . . . . . . . . . 13 3.1.1 Efficiency of the scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.2 Unconditional stability of the BDF2 scheme . . . . . . . . . . . . . . . . . . . 14 3.1.3 Uniform in time estimates for the BDF2 scheme . . . . . . . . . . . . . . . . 16 3.1.4 Uniform in time H1(Ω) bound of the BDF2 scheme . . . . . . . . . . . . . . 19 3.1.5 Error analysis of the BDF2-FEM scheme . . . . . . . . . . . . . . . . . . . . 22 3.2 The second-order Adams-Moulton-Bashforth method (AMB2) . . . . . . . . . . . . . 27 3.2.1 Efficiency of the scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2.2 Unconditional stability of the AMB2 scheme . . . . . . . . . . . . . . . . . . 28 3.2.3 Uniform in time estimates for the AMB2 scheme . . . . . . . . . . . . . . . . 30 3.2.4 Uniform in time H1(Ω)-norm bound for the AMB2 scheme . . . . . . . . . . 32 3.3 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4 One type of third-order IMplicit-EXplicit (IMEX) method 42 4.1 Third-order Adams-Moulton-Bashforth (AMB3) scheme . . . . . . . . . . . . . . . . 42 4.2 Efficiency of the scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.3 Important lemmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.4 Unconditional stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.5 Long-time stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.6 Error analysis of the semi-discrete scheme . . . . . . . . . . . . . . . . . . . . . . . . 52 4.7 Numerical results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 iv 5 Uncertainty quantification of contaminant transport 61 5.1 Convection-Diffusion equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 5.2 Numerical algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 5.3 Quantity of interest (QoI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.3.1 Source of uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 5.3.2 Quantity of interest for contaminant transport . . . . . . . . . . . . . . . . . 64 5.3.3 Karhunen-Loe`ve (KL) expansion . . . . . . . . . . . . . . . . . . . . . . . . . 64 5.4 Methods for stochastic PDE with random input data . . . . . . . . . . . . . . . . . . 65 5.4.1 Monte Carlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.4.2 Sparse grids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.5 Numerical results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.5.1 Numerical convergence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.5.2 Uncertainty quantification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 6 Summary 74 Appendix A Important inequalities 75 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Biographical Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 v LIST OF TABLES 3.1 RelativeerrorandorderofaccuracywithrespecttothespatialgridsizehforExample 1 at t = 1 and with ∆t = h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.2 Same information as in Table 3.1 but for ∆t = h3.5/2. . . . . . . . . . . . . . . . . . . 36 3.3 Same information as in Table 3.1 but for ∆t = h2 . . . . . . . . . . . . . . . . . . . . 37 3.4 RelativeerrorandorderofaccuracywithrespecttothespatialgridsizehforExample 3 at t = 1 and with ∆t = h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 4.1 RelativeerrorandorderofaccuracywithrespecttothespatialgridsizehforExample 1 at t = 1 and with ∆t = h. r = r defined by (4.47) . . . . . . . . . . . . 56 terminal 1/512,1 5.1 Numerical Error and Convergence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.2 Comparison between Monte Carlo and Sparse grid Methods . . . . . . . . . . . . . . . 68 5.3 Comparison of QoI and QoI between different spatial grid sizes using Sparse Grid 1 2 Hermite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 5.4 Comparison of QoI and QoI between different spatial grid sizes using Sparse Grid 3 4 Hermite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 5.5 UncertaintyQuantificationofα independentlyusingSparseGridClenshaw-Curtis BJSJ for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 1 2 5.6 UncertaintyQuantificationofinflowindependentlyusingSparseGridClenshaw-Curtis for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 1 2 5.7 Uncertainty Quantification of outflow independently using Sparse Grid Clenshaw- Curtis for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 1 2 5.8 UncertaintyQuantificationofα independentlyusingSparseGridClenshaw-Curtis BJSJ for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 3 4 5.9 UncertaintyQuantificationofinflowindependentlyusingSparseGridClenshaw-Curtis for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 3 4 5.10 Uncertainty Quantification of outflow independently using Sparse Grid Clenshaw- Curtis for QoI and QoI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 3 4 vi LIST OF FIGURES 2.1 The physical domain consisting of a porous media Ω and a free-flow conduit Ω . . . . 5 p f 3.1 Relative error for ϕ in Example 3 for BDF2 (left) and AMB2 (right) up to t = 100 for h = 1/64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 Same information as for Figure 3.1 but for u . . . . . . . . . . . . . . . . . . . . . . . 38 f 3.3 Same information as for Figure 3.1 but for p. . . . . . . . . . . . . . . . . . . . . . . . 38 3.4 Energy E over time t. ν = S = g = α = 1, γ = γ = g/5, K = 10 6 and h = 1/20 39 BJSJ p f − 3.5 Energy E over time t. S = 10 6, ν = g = α = 1, γ = γ = g/5, K = 10 6 and − BJSJ p f − h = 1/20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.6 Energy E over time t. ν = S = g = α = 1, γ = γ = g/10, K = 10 6 and BJSJ p f − h = 1/20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.7 Energy E over time t. ν = 10 1, S = g = α = 1, γ = γ = g/5, K = 10 6 and − BJSJ p f − h = 1/20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.1 Relative error for hydraulic head ϕ (left) and velocity ⃗u (right) up to t = 100 for h = 1/64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 4.2 Relative error for pressure p up to t = 100 for h = 1/64. . . . . . . . . . . . . . . . . . 57 4.3 Long-time behavior of energy functional E +E (left) and E (right) . . . . . . . . . 57 ϕ u p 4.4 Long-time behavior of energy functional E +E , ν = 0.0001 . . . . . . . . . . . . . . 58 ϕ u 4.5 Long-time behavior of energy functional E , ν = 0.0001 . . . . . . . . . . . . . . . . . 58 p 4.6 Long-time behavior of energy functional E +E , K = 0.01I . . . . . . . . . . . . . . 58 ϕ u 4.7 Long-time behavior of energy functional E , K = 0.01I . . . . . . . . . . . . . . . . . 59 p 4.8 Long-time behavior of energy functional E +E , K = 0.01I, γ = γ = g/2 . . . . . 59 ϕ u f p 4.9 Long-time behavior of energy functional E , K = 0.01I, γ = γ = g/2 . . . . . . . . . 59 p f p vii ABSTRACT The dissertation includes two parts. The first part consists of designing and analyzing high order long-timeaccuratenumericalmethodsforStokes-Darcysystem. Weproposesecondandthird-order efficient and long-time accurate numerical methods, called IMplicit-EXplicit methods (IMEX) for the coupled Stokes-Darcy system. Although the original continuum Stokes-Darcy PDE system is fullycoupled,ouralgorithmiscapableofdecouplingthesystemintotwosub-systemssothatasingle Stokes and a single Darcy system can be computed in a parallel fashion without iteration. All the schemes we proposed are proven to be unconditionally stable and long-time stable. The bound on theerrorisuniform-in-time,whichisamongthefirstofthiskindforsecondandthird-ordermethods of Stokes-Darcy system. Error estimates for the second order Backward-Differentiation scheme are proved. The second part concerns the Uncertainty of Quantification (UQ) of the contaminant transport. We compute the convection-diffusion equation with Streamline Upwind Petrov-Galerkin (SUPG) method. The quantity of interest is acquired using Monte Carlo and Sparse Grid methods in order to study the sensitivity with respect to the random parameters. viii CHAPTER 1 INTRODUCTION Karst is a type of landscape which contains special rocks, such as limestone and dolomite. Due to the chemical reaction involving carbon dioxide and water, rock will gradually dissolve so that tunnels and vugs are formed. As long as the water supply is sufficient, the tunnels and vugs will develop into large holes and various shapes of rocks. The dissolution process will stop when there is no more water, and the rock’s shape change will reach a steady state. A typical example is the Yosemite area in California. A karst aquifer is a type of aquifer with this unique karst landscape and is important to our daily lives. According to a geological survey, about 40% of drinking water in the United States comes from a karst aquifer. Moreover, the number is around 90% in Florida [35]. Karst aquifers are very vulnerable to pollution due to human activities, including litters, pesticides and polluted rain. Thus, it is crucial to study the flow motion and contaminant transport in a karst aquifer [37]. Due to the difficulty studying the karst aquifer, including heterogeneity of the porous media part and the complicated conduit geometry, many hydrogeologists neither have the appropriate mathematical models to compute nor enough information to study a karst aquifer. Thus, it is very difficult to provide policy makers with useful suggestions and guidance about utilizing, developing and protecting karst aquifers. Since contaminants are transported very slowly from one location to another, we need to compute the numerical solution for large time. However, the standard stability does not preclude exponential growth of the solution on a finite interval. This may become a problem even with exact initial conditions due to rounding error. If the terminal time is very large, there is no way to trust the numerical results as it will most likely be ruined by amplified rounding errors. Besides accuracy, the computational cost is also a concern for long-time simulations. In this dissertation, several high-order efficient and long-time accurate schemes are proposed and analyzed. High-order schemes usually enable us to use a larger time step than low-order schemes while maintaining the same accuracy, which also reduce the computational costs. 1

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