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Assessment and Improvement of Computational Fluid Dynamics Methods for Separated Turbulent Flows at Low Reynolds Numbers

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Assessment and Improvement of Computational Fluid Dynamics Methods for Separated Turbulent Flows at Low Reynolds Numbers Michigan Technological University Digital Commons @ Michigan Tech Dissertations, Master's Theses and Master's Reports 2020 ASSESSMENT AND IMPROVEMENT OF COMPUTATIONAL FLUID DYNAMICS METHODS FOR SEPARATED TURBULENT FLOWS AT LOW REYNOLDS NUMBERS Tom Mancuso Michigan Technological University, [email protected] Copyright 2020 Tom Mancuso Recommended Citation Mancuso, Tom, "ASSESSMENT AND IMPROVEMENT OF COMPUTATIONAL FLUID DYNAMICS METHODS FOR SEPARATED TURBULENT FLOWS AT LOW REYNOLDS NUMBERS", Open Access Dissertation, Michigan Technological University, 2020. https://doi.org/10.37099/mtu.dc.etdr/1072 Follow this and additional works at: https://digitalcommons.mtu.edu/etdr Part of the Heat Transfer, Combustion Commons ASSESSMENT AND IMPROVEMENT OF COMPUTATIONAL FLUID DYNAMICS METHODS FOR SEPARATED TURBULENT FLOWS AT LOW REYNOLDS NUMBERS By Thomas Mancuso A DISSERTATION Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY In Mechanical Engineering - Engineering Mechanics MICHIGAN TECHNOLOGICAL UNIVERSITY 2020 © 2020 Thomas Mancuso This dissertation has been approved in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY in Mechanical Engineering-Engineering Mechanics. Department of Mechanical Engineering - Engineering Mechanics Dissertation Co-advisor: Dr. Abhijit Mukherjee Dissertation Co-advisor: Dr. Craig R. Friedrich Committee Member: Dr. Fernando L. Ponta Committee Member: Dr. Seong-Young Lee Committee Member: Dr. Gustavo A. Ledezma Department Chair: Dr. William Predebon TABLE OF CONTENTS LIST OF FIGURES ..................................................................................................................... VI LIST OF TABLES ...................................................................................................................... XII PREFACE .................................................................................................................................. XIII ACKNOWLEDGEMENTS ........................................................................................................ XV NOMENCLATURE ................................................................................................................. XVI ABSTRACT ............................................................................................................................. XIX 1 INTRODUCTION ................................................................................................................. 1 1.1 Turbulent Energy Cascade ............................................................................................. 3 1.2 Applications ................................................................................................................... 7 1.2.1 Electric Machinery ................................................................................................. 7 1.2.2 Other applications ................................................................................................ 10 2 MODEL FORMULATION.................................................................................................. 11 2.1 Governing Equations .................................................................................................... 11 2.2 Turbulence Models ....................................................................................................... 16 2.2.1 SST ....................................................................................................................... 16 2.2.2 Scale Adaptive Simulation ................................................................................... 19 2.2.3 Reynolds Stress Model ......................................................................................... 21 2.2.4 Partially Averaged Navier-Stokes ........................................................................ 23 2.2.5 Detached Eddy Simulation ................................................................................... 27 2.2.6 Large Eddy Simulation ......................................................................................... 29 3 TEST CASES....................................................................................................................... 32 iii 3.1 Staggered tube bank ..................................................................................................... 32 3.2 Square in cross flow ..................................................................................................... 41 4 METHODS OF ANALYSIS ................................................................................................ 47 4.1 Mesh Creation .............................................................................................................. 47 4.2 Problem Configuration ................................................................................................. 48 4.2.1 CFD model conditions .......................................................................................... 48 4.2.2 Solution Methods ................................................................................................. 49 4.2.3 Transient results ................................................................................................... 50 4.2.4 Time averaging solution ....................................................................................... 51 4.3 Mesh Independence ...................................................................................................... 54 4.4 Calculating Reynolds Stresses ...................................................................................... 57 5 RESULTS OF COMPARITIVE STUDY ............................................................................ 59 5.1 Staggered tube bank ..................................................................................................... 59 5.1.1 Assessment frequency domain analysis and degree or resolved turbulence for the staggered tube bank.............................................................................................................. 71 5.1.2 Heat transfer and flow profiles for the staggered tube bank ................................. 74 5.2 Square in cross flow ..................................................................................................... 82 5.2.1 Assessment frequency domain analysis and degree or resolved turbulence for the square in cross flow ............................................................................................................. 96 5.2.2 Heat transfer and flow profiles for the square in cross flow ................................. 99 5.3 Summary of results .................................................................................................... 104 5.4 Evaluation of Accuracy relative to Computational cost.............................................. 106 6 IMPROVEMENT OF SCALE ADAPTIVE SIMULATION MODEL FOR SST.............. 110 6.1 Model basis and derivation ......................................................................................... 110 6.2 Review of recently published work ............................................................................ 120 6.3 Improvement to the Scale Adaptive Simulation Model .............................................. 122 6.3.1 Rationalization for improvement ........................................................................ 122 6.3.2 Evaluation of SST-SAS model parameters ......................................................... 125 6.3.3 Schemes to improve the accuracy of the SST-SAS model for the present cases . 130 6.3.4 Results of improvement ...................................................................................... 133 6.4 Conclusions for attempted improvement to the SST-SAS model ............................... 144 7 CONCLUSION .................................................................................................................. 146 iv 8 REFERENCE LIST ........................................................................................................... 147 A. IMPLEMENTATION OF TURBULENCE MODELS IN FLUENT ................................. 154 Source code for Fluent UDFs ............................................................................................. 156 B. TIME AVERAGED PARAMETERS FROM TRANSIENT SOLUTIONS ...................... 178 Staggered tube bank SST detailed results .......................................................................... 179 Staggered tube bank SST-SAS detailed results .................................................................. 180 Staggered tube bank RSM detailed results ......................................................................... 181 Staggered tube bank PANS-SST detailed results ............................................................... 182 Staggered tube bank DES detailed results .......................................................................... 183 Staggered tube bank LES detailed results .......................................................................... 184 Square in cross flow SST detailed results .......................................................................... 185 Square in cross flow SST-SAS detailed results .................................................................. 186 Square in cross flow RSM detailed results ......................................................................... 187 Square in cross flow PANS-SST detailed results ..............................................................
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