CONTENTS 



FOREWORD AND ACKNOWLEDGMENTS v 



EXECUTIVE SUMMARY vi 



NOMENCLATURE AND LIST OF SYMBOLS ix 



LIST OF FIGURES xii 



1. INTRODUCTION 1 



1.1 Objectives 1 



1.2 Background 2 



1.3 NAVFAC/CEL Research Program in Cable Strumming 3 



1.4 Scope of the Report 4 



2. CROSS FLOW STRUMMING OSCILLATIONS 4 



2.1 Resonant Cross Flow Response Characteristics 4 



2.2 Hydrodynamic Forces 9 



2.3 Coherence of Shedding due to Lock-on 14 



2.4 Reynolds Number Effects 17 



2.5 Yaw or Inclination Effects 19 



2.6 Surface Roughness Effects 21 



2.7 Shear (Nonuniform Flow) Effects 23 



3. EXPERIMENTAL STRUMMING RESULTS 52 



3.1 Behavior of Cables in Fluid Flows 52 



3.2 Towing and Flow Channel Experiments 53 



3.3 Small-Scale Field Experiments 60 



3.4 Large-Scale Field Experiments 62 



4. STRUMMING CALCULATION METHODS 87 



4.1 Analytical Models 87 



4.2 General Design Procedures 88 



4.3 Practical Design Data 91 



5. NUMERICAL MODELS FOR STRUMMING ANALYSIS AND 



ASSOCIATED STRUCTURAL MODELING 99 



5.1 NATFREQ, a Strumming Prediction Model 99 



5.2 Cable Structure Static Analysis Models 100 



5.3 Other Computer Codes 102 



5.4 SEADYN, a Dynamic Analysis Model 103 



5.5 The SLAK Code 104 



