Air and Water (eBook)

René Moreau is emeritus professor at Grenoble Institute of Technology, a member of the French Academy of Sciences, and a member of the French Academy of Technology. He is a recognized specialist in the field of fluid mechanics, notably in magnetohydrodynamics, and the author of several books and more than 150 other publications on these subjects. This book was born of his desire to share his love of nature and of his wonderment of the phenomena it displays. As he says in the prologue: In essence, I hope to give the reader feeling that I am telling a beautiful story and of transmitting a sense of my awe and wonder of it all. From 1990 until 2012 he was the Series Editor of the Fluid Mechanics and Its Applications Bookseries, http://www.springer.com/series/5980

Reader's guide 6
Acknowledgments 7
Table of contents 8
Prologue 11
1 The atmosphere at rest 14
1. Structure of the atmosphere 15
2. Composition of the atmosphere 20
3. Propagation of waves in the atmosphere 27
3.1. Sound 27
3.2. Light 28
4. Heat exchange through the atmosphere 33
Conclusion 38
2 The atmosphere in movement 40
1. Large-scale circulation within the atmosphere 41
1.1. The trade winds, the HADLEY cell, and the subtropical jet stream 41
1.2. Polar cells, FERREL cell, and the polar jet stream 47
2. Low-pressure zones and cyclones 49
2.1. Formation and direction of rotation of atmospheric low-pressure zones 49
2.2. Quasi-two-dimensional structure of low-pressure zones 57
2.3. Trajectory and energy of depressions 62
3. Periodic phenomena in the atmosphere 66
3.1. Monsoons 66
3.2. The WALKER cell 68
3.3. Thermal winds, katabatic winds, and anabatic winds 68
3.4. Dappled skies and lee waves 72
Conclusion 74
3 The vagaries of the atmosphere 75
1. Birth and evolution of thunderstorms and tornados 76
1.1. Dynamics of thunderstorm formation 76
1.2. Tornado formation 79
2. Sonic and luminal signatures of thunderstorms 85
2.1. Lightning 85
2.2. Thunder 90
2.3. The lights of the upper atmosphere 91
2.4. Rainbows 93
3. The various precipitations 96
4. How are weather forecasts produced? 100
Conclusion 103
4 Heavier than air, how can they fly? 104
1. Lift and drag 105
1.1. Lift explained by pressure forces 105
1.2. Formation of vortices around a wing in flight 108
2. Why are airplanes so noisy? 114
3. Shock wave and sound barrier 117
Conclusion 120
5 The tranquil sea 121
1. The sea at rest 122
1.1. A first panoramic glimpse 122
1.2. Pressure, temperature, and salinity of seawater 125
1.3. The sea is neither flat nor round 129
2. Sound and light in seawater 132
3. The remarkable stability of ships 134
4. Global circulation in the oceans 137
Conclusion 142
6 The sea that we see dancing 143
1. The tides 144
2. The El Niño phenomenon 149
3. Swells and waves 152
3.1. How and why do waves propagate? 152
3.2. The surprising variety of waves 156
3.3. Ripples and convective instabilities under ice floe 162
Conclusion 164
7 Rivers and streams 166
1. The main properties of the great rivers 167
1.1. Length, depth, and speed distribution 167
1.2. Uniform regime 169
1.3. Nonuniform regimes 171
2. Curves and meanders 177
3. Waterfalls and cascades 180
Conclusion 181
8 Lakes, dams, and major works 183
1. From marshes to hydroelectric reservoirs 184
2. Large dams: stability and conforming to site 189
3. Management of large rivers 194
4. General structure of a hydroelectric facility 197
4.1. High-hydraulic head in mountainous regions 197
4.2. Medium hydraulic head 200
4.3. Facilities with small hydraulic heads 201
4.4. Other types of facilities 203
5. Large port facilities 203
Conclusion 206
Epilogue 208
1. What worries, and on what are they based? 209
1.1. Air pollution 210
1.2. Marine pollution 212
1.3. Freshwater resources 213
2. To conclude our journey 214
Appendix Instabilities and turbulence 216
1. The sudden appearance of movement 217
1.1. RAYLEIGH-BÉNARD instability 217
1.2. RAYLEIGH-TAYLOR instability 221
2. Sheared interfaces: the KELVIN-HELMHOLTZ instability 223
3. Other common vortex structures 226
4. Transition toward turbulence 229
4.1. Appearance of turbulence in unconfined flows 229
4.2. Transition toward turbulence in duct flows 231
4.3. Other ways to generate turbulence 232
5. Fully developed turbulence 233
5.1. Turbulence in the most common flows 233
5.2. Large-scale atmospheric turbulence 234
5.3. Inverse energy cascade in two-dimensional turbulence 237
Conclusion 239
Glossary 241
Index 258