Water Waves and Ship Hydrodynamics: An Introduction / Edition 2

by A.J. Hermans

Overview

In this book an introduction is given to aspects of water waves that play a role in ship hydrodynamics and offshore engineering. At first the equations and linearized boundary conditions are derived describing the non-viscous free surface water waves, with special attention to the combination of steady and non-steady flow fields. Then some simple kinds of free wave solutions are derived, such as plane waves and cylindrical waves. For several situations, steady and unsteady, the source singularity function is derived. These functions play a role in numerical codes used to describe the motion of ships and offshore structures. These codes are mostly based on a boundary integral formulation; therefore we give an introduction to these methods. It is shown how first order ship motions can be determined. In offshore engineering the second order wave drift motions play an important role. An introduction to this phenomenon is given and the effects which have to be taken into account are explained by means of a simple example where we can determine nearly all the aspects analytically. An interesting example that is worked out is the motion of very large floating flexible platforms with finite draft. Finally an introduction to the theory of shallow water non-linear dispersive waves is presented, and shallow water ship hydrodynamics, that plays a role in coastal areas and channels is treated. Here attention is paid to the interaction between passing ships in restricted water. In the appendix a short introduction to some of the mathematical tools is given.

Product Details

ISBN-13:	9789400700956
Publisher:	Springer Netherlands
Publication date:	10/28/2010
Edition description:	2nd ed. 2011
Pages:	169
Product dimensions:	6.40(w) x 9.40(h) x 0.80(d)

Table of Contents

1 Theory of Water Waves 1

1.1 Basic Linear Equations 1

1.2 Boundary Conditions 2

1.3 Linearised Theory 4

1.3.1 Small Amplitude Waves in a Steady Current 5

1.3.2 Small Amplitude Waves in a Small Velocity Flow Field 7

2 Linear Wave Phenomena 11

2.1 Travelling Plane Waves 11

2.1.1 Plane Waves 11

2.1.2 Wave Energy Transport 14

2.2 Cylindrical Waves 18

2.3 Harmonic Source Singularity 20

2.4 The Moving Pressure Point 27

2.5 Wave Fronts 29

2.6 Wave Patterns 31

2.7 Singularity in a Steady Current 35

2.7.1 Steady Singularity 35

2.7.2 Oscillating Singularity 38

3 Boundary Integral Formulation and Ship Motions 41

3.1 Scattering of Acoustic Waves 41

3.1.1 Direct Method 44

3.1.2 Source Distribution 45

3.2 Scattering of Free Surface Waves 46

3.2.1 Fixed Object 47

3.2.2 Direct Method 49

3.2.3 Source Distribution 49

3.2.4 Motions of a Floating Object, Ship Motions 50

3.2.5 Heave Motion of a Floating Object 53

3.3 Slow Speed Approximation 56

4 Second-Order Theory 59

4.1 Second-Order Wave Theory 59

4.2 Wave-Drift Forces and Moments 62

4.2.1 Constant and Low Frequency Drift Forces by Means of Local Expansions 63

4.2.2 Constant Drift Forces by Means of Far-Field Expansions 65

4.3 Demonstration of Second-Order Effects, a Classroom Example 69

4.3.1 Interaction of Waves with a Vertical Wall 69

4.3.2 Forces on a Fixed Wall 71

4.3.3 Moving Wall 72

4.3.4 First-Order Motion of the Wall 73

4.3.5 Influence of the Motion on the Low Frequency Drift Force 77

4.3.6 Second-Order Motion of the Wall 77

4.3.7 Some Observations 78

5 Asymptotic Formulation 79

5.1 Thin Ship Hydrodynamics, Michell Theory 79

5.2 Short Wave Diffraction by a Sailing Ship 82

6 Flexible Floating Platform 87

6.1 The Finite Draft Problem 88

6.2 Semi-Analytic Solution 91

6.2.1 Semi-Infinite Platform 93

6.2.2 Strip of Finite Length 96

7 Irregular and Non-linear Waves 103

7.1 Wiener Spectrum 103

7.2 Shallow Water Theory 109

7.3 Non-linear Dispersive Waves 114

8 Shallow Water Ship Hydrodynamics 125

8.1 Thin Airfoil Theory 125

8.2 Slender Body Theory 133

8.3 Free Surface Effects 137

8.4 Ships in a Channel 146

8.5 Interaction of Ships 151

9 Appendices: Mathematical Methods 155

9.1 The Method of Stationary Phase 155

9.2 The Method of Characteristics 159

9.3 Singular Integral Equations 161

9.4 The Two-Dimensional Green's Function 162

9.5 Simplification of the Set of Algebraic Equations 163

References 165

Index 167