In this groundbreaking book, Adrian Bejan takes the recurring patterns in nature—trees, tributaries, air passages, neural networks, and lightning bolts—and reveals how a single principle of physics, the constructal law, accounts for the evolution of these and many other designs in our world. Everything—from biological life to inanimate systems—generates shape and structure and evolves in a sequence of ever-improving designs in order to facilitate flow. River basins, cardiovascular systems, and bolts of lightning are very efficient flow systems to move a current—of water, blood, or electricity. Likewise, the more complex architecture of animals evolve to cover greater distance per unit of useful energy, or increase their flow across the land. Such designs also appear in human organizations, like the hierarchical “flowcharts” or reporting structures in corporations and political bodies. All are governed by the same principle, known as the constructal law, and configure and reconfigure themselves over time to flow more efficiently. Written in an easy style that achieves clarity without sacrificing complexity, Design in Nature is a paradigm-shifting book that will fundamentally transform our understanding of the world around us.

Design happens everywhere, whether in animate objects (e.g., dendritic lung structures, bacterial colonies, and corals), inanimate patterns (river basins, beach slope, and dendritic crystals), social dynamics (pedestrian traffic flows), or engineered systems (heat dissipation in electronic circuitry). This “design in nature” often takes on remarkably similar patterns, which can be explained under one unifying Constructal Law. This book explores the unifying power of the Constructal Law and its applications in all domains of design generation and evolution, ranging from biology and geophysics to globalization, energy, sustainability, and security. The Constructal Law accounts for the universal tendency of flow systems to morph into evolving configurations that provide greater and easier access over time. The Constructal Law resolves the many and contradictory ad hoc statements of “optimality”, end design, and destiny in nature, such as minimum and maximum entropy production and minimum and maximum flow resistance, and also explains the designs that are observed and copied in biomimetics. Constructal Law and the Unifying Principle of Design covers the fundamentals of Constructal Theory and Design, as well as presenting a variety of state-of-the-art applications. Experts from the biological, physical and social sciences demonstrate the unification of all design phenomena in nature, and apply this knowledge to novel designs in modern engineering, such as vascularization for self-healing and self-cooling materials for aircraft, and tree fins and cavities for heat transfer enhancement.

Design course on the universal principle of configurations in nature and engineering-the constructal law Design with Constructal Theory offers a revolutionary new approach based on physics for understanding and predicting the designs that arise in nature and engineering, from the tree and the forest to the cooling of electronics, urban design, decontamination, and vascular smart materials. This book shows how you can use the method of constructal theory to design human-made systems in order to reduce trial and error and increase the system performance. First developed in the late 1990s, constructal theory holds that flow architecture arises from the natural evolutionary tendency to generate greater flow access in time and in flow configurations that are free to morph. It unites flow systems with solid mechanical structures, which are viewed as systems for the flow of stresses. Constructal theory unites nature with engineering, and helps us generate novel designs across the board, from high-density packages to vascular materials with new functionalities (self-healing, self-cooling), and from tree-shaped heat exchangers to svelte fluid-flow and solid structures. Design with Constructal Theory starts with basic principles and then shows how these principles are applied to understanding and designing increasingly complex systems. Problems and exercises at the end of each chapter give you an opportunity to use constructal theory to solve actual design problems. This book is based on a design course developed by the two authors for upper-level undergraduates and graduate students at Duke University and other universities all over the world. With the authors' expert guidance, students and professionals in mechanical, civil, environmental, chemical, aerospace, and biomedical engineering will understand natural systems, and then practice design as science, by relying on constructal strategies to pursue and discover novel and effective designs.

Constructal theory has been extensively used to analyze and optimize many different shapes and structures in both living and non-living systems. It is generally considered to be a law that could govern the evolutions of shapes and structures in biology, physics, technology, and social organization. Accordingly, it seems that the constructal method is suitable for designing and analyzing all kinds of shapes and structures in the world. However, in most cases, the details for its applications were not carefully checked, meaning that it was often incorrectly applied, and that many unreasonable or inaccurate results were provided. This book systematically reviews and checks the applications of constructal theory in street design, economics, heat transfer optimization, flow systems, and explanations of natural structures and social phenomena. Every detail of the models, methods, optimizations, applications, results and conclusions is analysed, with careful consideration of theoretical derivations and typical examples. Accordingly, the problems and mistakes in the applications of the theory are directly pointed out and discussed in detail. The abuse and limitation of the constructal approach are also discussed. In many cases, it is shown that the theory has significant flaws and is even not applicable in certain circumstances. As constructal theory is widely used in the analysis and design of shapes and structures, this book will be essential for scientists, researchers, engineers, teachers, postgraduates and undergraduates in the fields of structure analysis, design and optimization in physics, biology, flow dynamics, heat transfer and thermodynamics.

An empowering new view of the nature of physics and the constant evolution of our physical and social world

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.

The book begins with familiar designs found all around and inside us (such as the ‘trees’ of river basins, human lungs, blood and city traffic). It then shows how all flow systems are driven by power from natural engines everywhere, and how they are endlessly shaped because of freedom. Finally, Professor Bejan explains how people, like everything else that moves on earth, are driven by power derived from our “engines” that consume fuel and food, and that our movement dissipates the power completely and changes constantly for greater access, economies of scale, efficiency, innovation and life. Written for wide audiences of all ages, including readers interested in science, patterns in nature, similarity and non-uniformity, history and the future, and those just interested in having fun with ideas, the book shows how many “design change” concepts acquire a solid scientific footing and how they exist with the evolution of nature, society, technology and science.