Shape and Structure, from Engineering to Nature

Adrian Bejan

Cambridge University Press, Oct 16, 2000 - Science - 324 pages

Seemingly universal geometric forms unite the flow systems of engineering and nature. For example, tree-shaped flows can be seen in computers, lungs, dendritic crystals, urban street patterns, and communication links. In this groundbreaking book, Adrian Bejan considers the design and optimization of engineered systems and discovers a deterministic principle of the generation of geometric form in natural systems. Shape and structure spring from the struggle for better performance in both engineering and nature. This idea is the basis of the new constructal theory: the objective and constraints principle used in engineering is the same mechanism from which the geometry in natural flow systems emerges. From heat exchangers to river channels, the book draws many parallels between the engineered and the natural world. Among the topics covered are mechanical structure, thermal structure, heat trees, ducts and rivers, turbulent structure, and structure in transportation and economics. The numerous illustrations, examples, and homework problems in every chapter make this an ideal text for engineering design courses. Its provocative ideas will also appeal to a broad range of readers in engineering, natural sciences, economics, and business.

Contents

• Natural Form Questioning and Theory: 1
• 12 The Hardest Questions: 4
• 13 The Objective and Constraints Principle: 6
• Problems: 11
• References: 12
• Mechanical Structure: 14
• 22 External Shape: 16
• 23 Internal Structure: 18
• 24 Shape and Structure Together: 20
• 25 Column in End Compression: 22
• 26 The Concept of Better: 24
• Problems: 25
• References: 27
• Thermal Structure: 29
• 33 Volume Cooled by Forced Convection: 35
• 34 The Method of Intersecting the Asymptotes: 40
• 35 The Balance between StreamTravel Time and Diffusion Time: 41
• 36 Optimal Longitudinal Flow Pulsations: 42
• 37 From Constructal Principle to Internal Structure: 44
• 38 Cracks in Shrinking Solids: 45
• Problems: 49
• References: 50
• Heat Trees: 52
• 42 Elemental Volume: 53
• 43 First Construct and Growth: 56
• 44 Second and HigherOrder Constructs: 58
• 45 Constructal Law: 60
• 46 Tapered Channels and Optimal Angles: 62
• 47 ThreeDimensional Heat Trees: 65
• 48 TimeDependent Discharge from a Volume to One Point: 67
• Increasing Complexity in a Volume of Fixed Size: 69
• 410 Design with Unrestricted Elemental Features: 74
• 411 Constructal Heat Trees Are Robust: 77
• Problems: 79
• References: 80
• Fluid Trees: 82
• 52 Elemental Volume: 84
• 53 First and HigherOrder Constructs: 88
• 54 Channels with HagenPoiseuille Flow: 91
• 55 Optimization of VoidSpace Distribution: 92
• Increasing Complexity in a Volume of Fixed Size: 94
• 57 ThreeDimensional Fluid Trees: 99
• 58 Scaling Laws of Living Trees: 108
• Problems: 113
• References: 115
• Ducts and Rivers: 117
• 62 Optimal River Channel Cross Sections: 122
• 63 Optimal Duct Cross Sections: 127
• 64 Deterministic River Drainage Basins: 128
• 65 River Basins with Randomly Distributed Resistance to Erosion: 137
• 67 Constructal Fluid Trees are Robust: 142
• 68 Rivers of People: 144
• Problems: 145
• References: 147
• Turbulent Structure: 149
• 72 Why Do Icebergs and Logs Drift Sideways?: 150
• 73 The First and Smallest Eddy: 151
• 74 The Stepwise Growth of Mixing Regions: 157
• 75 The Onset of Rolls in Fluid Layers Heated from Below: 158
• 76 Partitioned Fluid Layer Heated from the Side: 161
• 77 Optimization of Flow Geometry in Layers Heated from Below: 163
• 78 Porous Layer Saturated with Fluid and Heated from Below: 169
• 79 Natural Structure in Multiphase Flow Systems: 174
• 710 Dendritic Crystals: 175
• Problems: 178
• References: 179
• Convective Trees: 181
• 82 TwoDimensional TShaped Plate Fins: 182
• 83 Umbrellas of Cylindrical Fins: 187
• 84 Fin Trees with Optimal PlatetoPlate Spacings: 189
• 85 Trees of Circular Fins: 198
• 86 Conduction in Interstitial Spaces and Convection in Channels: 202
• 87 ParallelPlate Channels: 203
• 88 Optimally Tapered ParallelPlate Channels: 208
• 89 Round Tubes: 212
• 810 Two Fluid Trees in Counterflow are One Tree for Convection: 215
• Problems: 216
• References: 218
• Structure in Power Systems: 219
• 91 Allocation of Heat Exchange Inventory: 220
• 92 Distribution of Insulation: 223
• 93 Structure in LowTemperature Machines: 226
• 94 Streams in Counterflow: 230
• 95 Flying Machines and Animals: 234
• 96 Flying Carpets and Processions: 240
• Problems: 242
• References: 244
• Structure in Time Rhythm: 246
• 101 Intermittent Heat Transfer: 247
• 102 Defrosting Refrigerators: 249
• 103 Cleaning Power Plants: 252
• 104 Breathing: 254
• 105 Heart Beating: 257
• 106 The Effect of Animal Body Size: 260
• Problems: 267
• References: 268
• Transportation and Economics Structure: 270
• 111 Minimum Travel Time: 271
• 112 Minimum Cost: 278
• 113 Maximum Revenue: 283
• 114 Development of Economics Structure in Time: 287
• 115 Optimally Shaped Triangular Areas: 288
• 116 Older Methods in Spatial Economics: 293
• 117 The Law of Refraction: 295
• 118 The Law of Parsimony: 296
• Problems: 297
• References: 298
• Shapes with Constant Resistance: 300
• 122 More Degrees of Freedom: 301
• 123 More Efficient Structures Look More Natural: 308
• 124 More Material Where the Need is Greater: 311
• 125 An Old and Prevalent Natural Phenomenon: 312
• References: 314
• About the Author: 315
• Author Index: 317
• Subject Index: 320

Bibliographic information

• Title: Shape and Structure, from Engineering to Nature; Shape and Structure, from Engineering to Nature, Adrian Bejan
• Author: Adrian Bejan
• Edition: illustrated
• Publisher: Cambridge University Press, 2000
• ISBN: 0521793882, 9780521793889
• Length: 324 pages
• Subjects: Science / Life Sciences / Zoology / General; Technology & Engineering / Engineering (General); Technology & Engineering / Industrial Design / General; Technology & Engineering / Mechanical; Technology & Engineering / Structural