Faculty Profile: Sharon Swartz, PHD

Sharon Swartz
Sharon Swartz, PHD
Professor of Biology and Engineering
Ecology & Evolutionary Biology, Engineering
Work: +1 401-863-1582
My research seeks to understand the evolution of animal architecture and biological materials, and how they are influenced by the physical world. I work to understand the mechanistic basis of flight in bats not only to illuminate how bats fly, but to understanding how flight originated and diversified. Flying animals share characteristics dictated by constraints of physics, and I seek to delineate aspects of structure, physiology, and mechanics that uniquely shape bat flight.

Biography

Sharon received her undergraduate training in Biology and Anthropology/Sociology at Oberlin College, graduating with Highest Honors in 1981. After time away from school, she went on to graduate study in the Committee on Evolutionary Biology at The University of Chicago, and completed her doctorate in 1988, focusing on biomechanical approaches to understanding evolutionary patterns in the mammalian limb skeleton. In 1987, she joined the faculty of Northwestern University in the interdisciplinary Primate Biology Graduate Program. Around this time, she turned her attention from primate locomotion to bat flight, while maintaining active interests in fundamental aspects of size and scale in the architecture of bones. Her work on bats includes studies of mechanical properties of tissues of the bat wing, dynamics of wing movements during flight, fluid dynamics of highly flexible airfoils, and aerodynamics and energetics of bat flight, and her active collaborations link biology to engineering, computer science, and mathematics.

Institutions

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Research Description

Animals move through their environments in myriad ways, influencing all aspects of their natural history. These patterns of movement depend on intricate systems of organs and tissues that are amenable to structural and mechanical analyses. The study of locomotor systems can provide an ideal context in which to explore structure â€ââ'¬Å" function relationships and the evolution of morphological design.

Structure & Motion of Bat Wings

Biologists have long viewed the flapping wings of flying vertebrates as analogous to the stationary, rigid airfoils of fixed-wing aircraft. But small, slowly moving flying animals experience viscosity effects far greater than even the smallest of aircraft. At this scale, flow over foils becomes turbulent, unsteady, and unpredictable. Basic parameters such as wing aspect ratio, angle of attack, and camber can influence flow patterns and aerodynamic forces in dramatically different ways than in faster flows.

Our lab integrates biological and physical studies of natural and naturalistic flight in living bats, studies of robotic bat wings and simpler physical models, and computational simulations. The methods we have developed to document complex wing motions have helped us show that dynamically changing 3D wing topology is the rule, even in simple straight-line flight. Even more dynamic wing motions are employed in turning and other maneuvers. Our investigations of the material properties of bat wing tissues show that bat wing bones vary greatly in mineral content, so range from highly mineralized and very stiff near the body to nearly cartilaginous and highly compliant at the wing tips. Bat wing skin is also unique, balancing the extreme mechanical demands of flight with the energetic benefits of reducing weight. We have found that the gross architecture of the wing skin’s collagen-elastin network allows a single wing to encompass an extraordinary range of mechanical characteristics.

Experimental Fluid Dynamics

Adapting techniques from experimental fluid dynamics, we can study wakes made by bats to better understand how these animals produce the forces employed in their distinctive flight. We carry out wind tunnel studies of bat wakes, coupled with detailed kinematics at high temporal and spatial resolution. We have found that the wing movements employed by bats generate characteristic wakes that have similarities with and differences from those of birds and insects. Wake structure can also differ almost as much among bat species as between a bird and a bat of comparable mass.

Our physical modeling experiments capture important aspects of the bat flight apparatus in simplified, abstracted form. Unlike the stiff wings of birds and insects, bats and gliding mammals employ airfoils made of stretchy or compliant material. Our pioneering work in compliant airfoils has demonstrated their remarkable capacity to generate lift at zero and very high angles of attack. We have found that the physical basis for this phenomenon lies in part in the self-cambering ability of compliant airfoils, which facilitates persistence of attached flow in conditions that would cause rigid airfoils to stall.

Our most sophisticated physical models are bat-like robots that capture many aspects of realistic bat flight with high fidelity, but allow us to independently modulate characteristics of the wingbeat in a manner that is impossible in living animals. These experiments help us study force production and flow dynamics, and give us controlled conditions under which we can tease apart the effect of motion and materials on aerodynamics and energetics.

Aeroecology

A few years ago, my colleague and friend Tom Kunz paid a visit to me from Boston University. He sat in my office, looked directly at me and announced, grinning, “There are fields called terrestrial ecology and marine ecology. It’s time to have Aeroecology.â€Ã' Tom challenged me to help him define what the recognition of such a discipline might mean to those who study animal flight. The physical environment of the aerosphere is both complex and dynamic, and poses many challenges to the locomotor systems of flying animals. For example, airflows are altered and modulated by motion over and around natural and human-engineered structures, and turbulence is introduced by technologies such as aircraft and wind farms. An aeroecological approach can help better understand mechanics, energetics, sensing of aerial flows, and motor control of flight. From this perspective, we can begin to analyze group flight behaviors of bats, as when immense colonies exit caves for evening foraging. In the long run, we aim to link the study of flight behavior in nature to the more carefully controlled studies of flight mechanics and energetics that we carry out in the lab.

Grants and Awards

2013 Distinguished Alumni Service Award, The University of Chicago
2013 Selected for NSF Exhibit, AAAS National Meeting
2013/16 Brown Randall Advisor
2012/13 TEAM Advising Program Leader
2012 Featured Researcher, Air Force Office of Scientific Research 60th Anniversary Video
2011 Elected Chair, Division of Comparative Biomechanics, Society for Integrative and Comparative Biology
2010 Karen T. Romer Prize for Excellence in Advising
2009/12 Brown Faculty Advising Fellow
2007 NSF/Science Visualization Contest, First place
2000 Deanââ'¬â"¢s Excellence in Teaching Award, Brown Medical School
1999 American Medical Women's Association Gender Equity Award
1999 Hooder, Brown University School of Medicine
1995/99 Marshall, Brown University School of Medicine Commencement Exercises
1992 Mary Putnam-Jacobi Award for the Outstanding Woman Medical Faculty Member, Brown Women in Medicine
1985/86 Harper Memorial Doctoral Fellowship, The University of Chicago
1982/85 Searle Graduate Fellowship, The University of Chicago
1981 Phi Beta Kappa

Affiliations

Society for Integrative and Comparative Biology, Divisions of Comparative Biomechanics, Vertebrate Morphology, and Comparative Physiology and Bioechemistry
North American Bat Research Society
International Society for Vertebrate Morphology
Society for Experimental Biology
American Physical Society, Division of Fluid Dynamics

Funded Research

Current Research Grants:

Air Force Office of Scientific Research: High Speed Kinematics and Velocimetry Equipment for Biological and Cyber-Physical Studies, Defense University Research Instrumentation Program (co-PI, with K. Breuer, PI and S. Mandre, co-PI, School of Engineering, and T. Roberts, co-PI). $ 520K.

National Science Foundation: Collaborative Research: Structure and Mechanics of the Bat Wing Membrane, from Directorate for Biology, Integrative Organismal Systems Program (PI, with N. Goulbourne, University of Michigan, co-PI). $666K.

Air Force Office of Scientific Research: Dynamics of Bat Wing Musculature, from Sensory Information Systems Program (PI, with T. Roberts, co-PI). $1,224K

Air Force Office of Scientific Research: Aerodynamics and Mechanics of Flight Robusticity in Bats: Animal Flight and Physical Model Experiments for Flapping MAV Applications, from Flow Interactions and Control Progam (PI, with K. Breuer, School of Engineering, co-PI), $517K

Completed Research Grants:
2010-2013: Air Force Office of Scientific Research, Multi University Research Initiatives (MURI): "Supplement to Biologically Inspired Flight for Micro Air Vehicles" (K. Breuer, PI, Co-PI with C. Moss (U. Maryland). $282K.

2009-2011: Air Force Office of Scientific Research: "Reconfigurable, Hovering, Ultra-Maneuverable Bat Technologies (RHUMBAT)" (co-PI with co-PIs S. Joshi, NextGen Aeronautics, G. Reich, Wright-Patterson Air Force Base, and N. Goulbourne, Virginia Tech), $750K.

2009-2011 Air Force Office of Scientific Research Defense University Research Instrumentation Program (DURIP): "Acquisition of an Advanced Thermal Infrared Imaging System for Tracking Multiple Targets in Three Dimensions" (co-PI with T. Kunz, PI, Boston University). $525,000.

2008-2011 NSF ADVANCE Career Development Award: "Skins of 'Bone': The Mechanics and Structural Design of the Insect Exoskeleton" $20K.
2007-2012 Air Force Office of Scientific Research, Multi University Research Initiatives (MURI): "Biologically Inspired Flight for Micro Air Vehicles" (K. Breuer, PI, Co-PI with M. Drela and J. Peraire (MIT), C. Moss (U. Maryland), and B. Batten (Oregon State University). $6,200K

2007-2011 Keck Foundation: "Phase II Proposal: A Proposal to Design and Build a Dynamic Skeletal Imaging System" (PI: E. Brainerd) $1,800K

2007-2010 National Science Foundation: Bat Wing Structure and the Aerodynamic Mechanisms of Flapping Flight. (PI, D. Laidlaw and K. Breuer, co-PIs). $280K.

2006 Department of Defense, Defense University Instrumentation Program: "High-speed Motion Analysis and Particle Velocimetry System for Studies in Maneuvering Flight in Bats" (PI, K. Breuer co-PI) $488K

2006 Air Force Office of Scientific Research: "Supplement to Aeromechanics of Highly Maneuverable Bats" (PI, K. Breuer co-PI) $85K

2005-2008 Air Force Office of Scientific Research: "Aeromechanics of Highly Maneuverable Bats" (PI, K. Breuer co-PI) $450K

2005-2008 National Research Service Award to Kevin Middleton (Sponsor) $100K

2005-2007 National Science Foundation: "DDDAS-TMRP: Interactive Data-driven Flow-simulation Parameter Refinement for Understanding the Evolution of Bat Flight" (D. Laidlaw, PI, co-PI with K. Breuer) $150K

2004-2009 National Science Foundation: "Computational simulation, modeling, and visualization for understanding unsteady bioflows" (D. Laidlaw, PI, co-PI with G. Karniadakis and P. Richardson) $650K

2004-2006 National Science Foundation: "DISSERTATION RESEARCH: Gliding Aerodynamics and the Origin of Bat Flight" (PI, graduate student Kristin Bishop co-PI) $10K

2004-2005 Brown University Salomon Research Fund: "Aerodynamic mechanisms of bat flight: an integrated multidisciplinary approach" (PI, K. Breuer and D. Laidlaw co-PIs); $20K

2003 National Science Foundation, MRI Program: "A volumetric imaging system for reconstruction of macroscopic fluid flows in organismic biology" (G. Lauder, A. Biewener, N. Holbrook and H. Stone, Harvard University, PIs, co-Investigator with C. Wilga, University of Rhode Island) $130K

2002-2003 National Science Foundation, CCLI Program: "Context-Rich Interactive Science Teaching and Learning System" (Thomas Webb, III, PI, co-PI with David Cutts, David Targan, and Nancy Pollard) $74K

2002-2003 NASA Space Grant Scholarship support to undergraduate research student Noa Kay, $3K

2000-2003 National Science Foundation: "Aerodynamics, Wing Biomechanics, and the Evolutionary Diversification of the Chiroptera". (PI) $434K

1999-2000 National Science Foundation: "Aerodynamics, Wing Biomechanics, and the Evolutionary Diversification of the Chiroptera". (PI) $279K

1997-1999 National Science Foundation: "Aerodynamics, Wing Biomechanics, and the Evolutionary Diversification of the Chiroptera". (PI) $73K

1996-1997 National Science Foundation: "The Biomechanics of Bat Flight: Skeletal architecture and functional performance". (PI) $190K

1995-1997 Whitaker Foundation: "New biomechanical approaches to understanding plasticity and functional significance in trabecular bone architecture". (PI)

1995-1996 National Science Foundation: "Development of a variable flow seawater flume and high-speed video imaging system". (co-Investigator with J. Witman and T. Goslow).

1995 The Rhode Island Foundation: "Basic biomechanics of trabecular bone tissue: a novel small animal model". (PI) $152K

1992-1995 National Science Foundation: "The Biomechanics of Bat Flight: Skeletal architecture and functional performance". (PI) $190K

Teaching Experience

My Teaching focuses on the integration of approaches from the physical and mathematical sciences with organismal and evolutionary biology. Biological Design (Bio 0400) uses basic math, physics, and engineering to better understand the materials and structures of a wide diversity of organisms, including animals, plants, fungi, and microbes. In Animal Locomotion, I employ a broad appraoch to understanding the ways animals move, including mechanics, energetics, physiology, ecology, and evolution. Although much of the course focuses on vertebrates, we also look at diverse cases from other groups of animals.

Courses Taught

  • Animal Locomotion (Biol 1800)
  • Biological Design: The Structural Architecture of Organisms (Biol 0400)

Selected Publications

  • Igor Pivkin, Eduardo Hueso, Rachel Weinstein, David H. Laidlaw, Sharon Swartz, and George Karniadakis. 2005. Simulation and Visualization of Air Flow Around Bat Wings During Flight. Proceedings of International Conference on Computational Science, pages 689-694, (2005)
  • Eduardo Hueso, Igor Pivkin, Sharon Swartz, David H. Laidlaw, George Karniadakis, and Kenneth Breuer. Visualization of Vortices in Simulated Airflow around Bat Wings During Flight. IEEE Visualization 2005 Poster Compendium, October 2005. (2005)
  • Jason S. Sobel, Andrew S. Forsberg, David H. Laidlaw, Robert C. Zeleznik, Daniel F. Keefe, Igor Pivkin, George E. Karniadakis, Sharon M. Swartz, and Peter Richardson. 2004. Particle Flurries: Synoptic 3D Pulsatile Flow Visualization. IEEE Computer Graphics and Applications April/May: 2-11. (2004)
  • Watts, P., E. J. Mitchell*, and S. M. Swartz. 2001. A computational model for estimating mechanics of horizontal flapping flight in bats. Model description and comparison with experimental results. Journal of Experimental Biology. 204: 2873-2898. (2001)
  • Swartz, S. M. 1997. Allometric patterning in the limb skeleton of bats: Implications for the mechanics and energetics of powered flight. Journal of Morphology, 234:277-294. (1997)
  • Swartz, S. M., A. Parker*, and C. Huo*. 1997. Theoretical and empirical scaling patterns and topological homology in bone trabeculae. Journal of Experimental Biology, 201:573-590. (1997)
  • Papadimitriou, H. M. *, S. M. Swartz, and T. H. Kunz. 1996. Ontogenetic and anatomic variation in mineralization of the wing skeleton of the Mexican free-tailed bat, Tadarida brasiliensis. Journal of Zoology, London, 240:411-426. (1996)
  • Swartz, S. M., M. D. Groves*, H. D. Kim* and W. R. Walsh. 1996. Mechanical properties of bat wing membrane skin: aerodynamic and mechanical functions. Journal of Zoology, London, 239:357-378. (1996)
  • Halgrimmsson, B.* and S. M. Swartz. 1995. Morphological adaptation in the hylobatid ulna: cross-sectional geometry and skeletal loading. Journal of Morphology 224:111-123. (1995)
  • Swartz, S. M., M. B. Bennett, and D. R. Carrier. 1992. Wing bone stresses in free flying bats and the evolution of skeletal design for flight. Nature 359:726-729. (1992)
  • Anton, S. C*., C. R. Jaslow and S. M. Swartz. 1992. Sutural complexity in artificially deformed human (Homo sapiens) crania. Journal of Morphology 214:321-322. (1992)
  • Bertram, J. E. A. and S. M. Swartz. 1991. The "Law of bone transformation": A case of crying Wolff? Biological Reviews of the Cambridge Philosophical Society 22(3):245-273. (1991)
  • Swartz, S. M. 1991. Strain analysis as a tool for functional morphology. American Zoologist 31(4):655-669. (1991)
  • Swartz, S. M. 1990. Pendular mechanics and the kinematics and energetics of brachiating locomotion. International Journal of Primatology 10(5):387-418. (1990)
  • Swartz, S. M. 1990. Curvature of the limb bones of anthropoid primates: overall allometric patterns and specializations in suspensory species. American Journal of Physical Anthropology 83(4):477-498. (1990)
  • Swartz, S. M. 1989. The functional morphology of weight bearing: limb joint surface area allometry in anthropoid primates. Journal of Zoology, London 218:441-460. (1989)
  • Swartz, S. M., A. A. Biewener, and J. E. A. Bertram. 1989. Telemetered in vivo strain analysis of locomotor mechanics of brachiating gibbons. Nature 342:270-272. (1989)
  • Swartz, S. M. 1987. Skeletal biomechanics and suspensory locomotion: preliminary results of in vivo bone strain analysis of brachiating gibbons. Proceedings of the American Society of Biomechanics 3:151-153. (1987)
  • Biewener, A. A., S. M. Swartz and J. E. A. Bertram. 1986. Bone modeling during growth: dynamic strain equilibrium in the chick tibia. Calcified Tissue International 39:390-395. (1986)