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.

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/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 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." 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.

National Science Foundation: Collaborative Research: The Rules of Predation: Linking Biomechanics and Ecology in the Bat-Insect Arms Race (co—PI, with A. Corcoran University of Colorado - Colorado Springs, PI and H. Vejdani, Lawrence Technologial University, co-PI). $861K total, Brown University component $257k.

Hyundai Visionary Challenge Part III: Robust Bat-inspired Aerial Robotics. (co-PI with Kenny Breuer) $150K.

Hyundai Visionary Challenge Part II: Robust Bat-inspired Aerial Robotics. (co-PI with Kenny Breuer) $50K.

Brown University Seed Funds Award: “Structure and mechanics of the bat shoulder: Testing a new model for human rotator cuff disorders”. $48K

Hyundai Visionary Challenge Part I: Robust Bat-inspired Aerial Robotics. (Faculty Sponsor, with Student Researchers Alberto Bortoni, Xiaozhou Fan, and Alexander Morris, and co-sponsor Kenny Breuer) $11K.

National Science Foundation:  MRI: Acquisition of an Animal Flight and Aeromechanics Wind Tunnel (co-PI, with K. Breuer, School of Engineering, PI). $1,038K.

Howard Hughes Medical Institute: Howard Hughes Medical Institute: HHMI Professorship Finalists STEM Education Development $20K.

Completed Research Grants:

2012-2016  National Science Foundation: National Robotic Initiative/Collaborative Research: Improving the Safety and Agility of Robotic Flight with Bat-Inspired Flexible-Winged Robots (co-PI, with K. Breuer, School of Engineering, co-PI and S. Hutchinson, T. Bretl, S-J. Chung, M. Golparvar-Fard, University of Illinois, co-PIs). $2,000K total, Brown University component $708K.

2012-2016  Air Force Office of Scientific Research: Dynamics of Bat Wing Musculature, from Sensory Information Systems Program (PI, with T. Roberts, co-PI). $1,224K

2011-2016  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). $404K.

2011-2014  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 Program (PI, with K. Breuer, School of Engineering, co-PI), $517K

2013-2014: 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

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). $525K

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. (D. Laidlaw and K. Breuer, co-PIs).  $279K

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) $50K

2004-2009  National Science Foundation: "Computational simulation, modeling, and visualization for understanding unsteady bioflows".  (co-PI with D. Laidlaw, G. Karniadakis, and P. Richardson) $662K

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

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

2002-2003  National Science Foundation, CCLI Program: “Context-Rich Interactive Science Teaching and Learning System” (co-PI with Thomas Webb, III, 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

1997-1999National 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

2014 Elizabeth LeDuc Award for Excellence in Teaching in the Life Sciences
2013 Distinguished Alumni Service Award, The University of Chicago
2013 Selected for NSF Exhibit, AAAS National Meeting
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 Dean's Excellence in Teaching Award, Brown Medical School
1999 American Medical Women's Association Gender Equity Award
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

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

My Teaching focuses on the integration of approaches from the physical and mathematical sciences with organismal and evolutionary biology. Biological Design: The structural architecture of organisms (Bio 0400) uses basic math, physics, and engineering to better understand the materials and structures of a wide diversity of organisms, including animals, plants, and fungi. 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.