Constructal theory of flow architecture of the lungs

Reis, A. Heitor; Miguel, António F.; Aydın, Murat

doi:10.1118/1.1705443

Cited by 147 publications

(103 citation statements)

References 11 publications

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“…Upon closer inspection, however, this explanation is questionable, because a larger paddle means a larger force exerted on the surrounding water body, not a higher efficiency. This body of work is just one application of the constructal law to the evolution of design in nature (e.g., Miguel, 2006;Reis, 2006a;Reis et al, 2004), which was reviewed in Hoppeler and Weibel (2005), Reis (2006b) and Bejan and Lorente (2010).…”

Section: Introductionmentioning

confidence: 99%

The constructal-law physics of why swimmers must spread their fingers and toes

Lorente¹,

Çetkin²,

Bello‐Ochende³

et al. 2012

Journal of Theoretical Biology

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Highlights The total force is 53% greater when the fingers are spaced optimally.  The optimal spacing is twice the boundary layer thickness of one finger.  The speed advantage comes from the greater force, which lifts more mass above water.  The theoretical predictions are confirmed by computational fluid dynamics simulations. AbstractHere we show theoretically that swimming animals and athletes gain an advantage in force and speed by spreading their fingers and toes optimally. The spacing between fingers must betwice the thickness of the boundary layer around one finger. This theoretical prediction is confirmed by computational fluid dynamics simulations of flow across two and four cylinders of diameter D.The optimal spacing is in the range 0.2D -0.4D, and decreases slightly as the Reynolds number (Re) increases from 20 to 100. The total force exerted by optimally spacing two cylinders exceeds by 53 percent the total force of two cylinders with no spacing when Re = 20. These design features hold for both time-dependent and steady-state flows.2

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Section: Introductionmentioning

confidence: 99%

The constructal-law physics of why swimmers must spread their fingers and toes

Lorente¹,

Çetkin²,

Bello‐Ochende³

et al. 2012

Journal of Theoretical Biology

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“…For the development of predictive models and methods necessary to identify general patterns and overarching principles, we need to define and articulate the limits of biological questions such that appropriate modeling techniques can be applied. Examples include the emergence of a metabolic theory of ecology (Brown et al 2004) and the application of thermodynamics to the configuration of organs (Reis et al 2004), organisms (Miguel 2006), and animal movement (Bejan and Marden 2006).…”

Section: New Opportunitiesmentioning

confidence: 99%

Addressing Grand Challenges In Organismal Biology: The Need For Synthesis

Padilla¹,

Daniel²,

Dickinson³

et al. 2014

BioScience

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Animals are complex systems operating at multiple spatial and temporal scales, facing the challenge of how to change in appropriate ways, degrees, and times, in response to the diverse internal and external influences to which they are exposed. Discovering the system-level attributes of organisms that make them resilient or robust-or sensitive or fragile-to change presents a grand challenge for biology. Knowledge of these attributes and the underlying mechanisms controlling them is crucially needed to predict how organisms will respond to short-and long-term changes in internal and external environments, including those driven by climate change. Organismal biologists require novel approaches that extend beyond traditional disciplinary boundaries, especially when they partner with mathematicians and engineers. Pursuing this research enterprise will not only give us a deeper understanding of how organisms will face future challenges, but it will also reveal nature-inspired solutions in complex engineered systems, both of which will benefit science and society.Keywords: organismal biology, grand challenges, integrative biology, systems engineering, predictive modeling Animals are inherently complex and are composed of multiple interconnected elements. They and their component elements must have the capacity to maintain stability and to simultaneously change in response to internal and external stimuli. For example, young animals must be able to process neurosensory inputs as they move through the environment while their brains and nervous systems continue to develop. As they grow and develop, structures used for locomotion may simultaneously change in their function and control because of changes in size and morphology (Hale 2014). Those same animals must maintain the internal physiological function of all of their systems throughout ontogeny and as they experience shifting internal 1 Dianna K. Padilla (padilla@stonybrook.edu) is a professor in the Department of Ecology and Evolution at Stony Brook University, in Stony Brook, New York. Thomas L. Daniel is a professor, in the Department of Biology, Billie J. Swalla is the director of and a professor in the the Friday Harbor Laboratories and in the Department of Biology, and Daniel Grünbaum is an associate professor in the School of Oceanography at the University of Washington, in Seattle. Patsy Dickinson is a professor in the Department of Biology and in the Neuroscience Program at Bowdoin College, in Brunswick, Maine. Cheryl Hayashi is a professor in the Department of Biology at the University of California, Riverside. Donal T. Manahan is a professor in the Department of Biological Sciences at the University of Southern California, in Los Angeles. James H. Marden is a professor in the Department of Biology at Pennsylvania State University, in State College. Brian Tsukimura is a professor in the Department of Biology at California State University, Fresno. 2 and external environments. In addition, animals and animal systems exhibit many nonlinear and time-dependent ...

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“…Symmetric branching rarely occurs in the human circulatory system but is common in the lung airway tree. Reis et al [6] used the rules (7) and (8), i.e. Murray's law to anticipate the structure of the human lung airway tree, namely the number of bifurcations -23 -that match optimal performance.…”

Section: Optimal Design Of Branching Flow Systemsmentioning

confidence: 99%

“…In their study, Bejan and co-workers not only derived the usual form of Murray's law, but also extended their analysis to turbulent flow and found a scaling law, akin of Murray's, in which the exponent is -3/7, instead of exponent -1/3 that holds for laminar flow. Based both on Murray's law and the Constructal Law, in 2004 Reis et al [6,7] were able to anticipate the lung airway structure, namely its 23 levels of branching, a well-known anatomic feature of the human lung.…”

Section: Introductionmentioning

confidence: 99%

Laws of non-symmetric optimal flow structures, from the macro to the micro scale

Reis¹

2012

AIP Conference Proceedings

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A constraint for the subgrid-scale stresses in the logarithmic region of high Reynolds number turbulent boundary layers: A solution to the log-layer mismatch problem Phys. Fluids 25, 015104 (2013) Intermittency and local dissipation scales under strong mean shear Phys. Fluids 25, 011701 (2013) Experimental investigation of relaminarizing and transitional channel flows Phys. Fluids 24, 124102 (2012) Work-based criterion for particle motion and implication for turbulent bed-load transport Phys. Fluids 24, 116604 (2012) Realizable versus non-realizable dynamic subgrid-scale stress models Phys. Fluids 24, 115105 (2012) Additional information on AIP Conf. Proc. Abstract. Many natural systems and engineering processes occur in which a fluid invades a territory from one entry point (invasion), or conversely is expelled from the territory through an outlet (drainage). In any such situation an evolutionary flow structure develops that bridges the gap between the micro-scale (diffusion dominant) and the macroscale (convection dominant). The respiratory and circulatory systems of animals are clear examples of complex flow trees in which both the invasion and drainage processes occur. These flow trees display successive bifurcations (almost always non-symmetric) which allow them to cover and serve the entire territory to be bathed. Although they are complex, it is possible to understand its internal structuring in the light of Constructal Law. A scaling law for optimal diameters of symmetric bifurcations was proposed by Murray (1926), while Bejan and coworkers (2000-2006) added a new scaling law for channel lengths, and based scaling laws of tree shaped structures on theoretical grounds. In this work we use the Constructal Law to study the internal structure and scaling laws of nonsymmetric flow structures, and show how the results might help understand some flow patterns found in Nature. We show that the global flow resistances depend on the parameter ξ=D 2 /D 1 =L 2 /L 1 defining the degree of asymmetry between branches 1 and 2 in a bifurcation. We also present a more accurate and general form, of Murray's law, as a result of the application of the Constructal law to branching flow structures. We end with a brief analysis of the use of these results in the analysis of flow structures of the human respiratory and circulatory systems.

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Constructal theory of flow architecture of the lungs

Cited by 147 publications

References 11 publications

The constructal-law physics of why swimmers must spread their fingers and toes

The constructal-law physics of why swimmers must spread their fingers and toes

Addressing Grand Challenges In Organismal Biology: The Need For Synthesis

Laws of non-symmetric optimal flow structures, from the macro to the micro scale

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