Administration

Kamran Mohseni

Professor Kamran Mohseni received his B.S. degree from the University of Science and Technology, Tehran, Iran, his M.S. degree in Aeronautics and Applied Mathematics from the Imperial College of Science, Technology and Medicine, London, U.K., and his Ph.D. degree from the California Institute of Technology (Caltech), Pasadena, CA, USA, in 2000.

He was a Postdoctoral Fellow in Control and Dynamical Systems at Caltech for almost a year. In 2001, he joined the Department of Aerospace Engineering Sciences, University of Colorado at Boulder. In 2011, he joined the University of Florida, Gainesville, FL, USA as the W.P. Bushnell Endowed Chaired Professor in the Department of Electrical and Computer Engineering and the Department of Mechanical and Aerospace Engineering. He is the Director of the Institue for Networked Autonomous Systems.


Heather B. Denson

Heather graduated from the University of Florida with her Bachelor of Science in Animal Biology. Heather’s research involves electrophysiological and neurophysiological investigations of biological control systems to identify neural connectivity pathways.


Post-doctoral Researchers

Dr. Mike Krieg

PERC Barbican

Mike primarily studies unconventional underwater propulsion, inspired by squid and other cephalopods, for use on unmanned underwater vehicles. This research focuses on jet formation and vortex ring dynamics, as they relate to propulsive performance. His research is mostly experimental, but he also investigates unsteady propulsion and analytical optimization.

References:
  • M. Krieg and K. Mohseni, Pressure and work analysis of unsteady, deformable, axisymmetric, jet producing cavity bodies, J. Fluid Mech. 769, 337-368, 2015.
  • M. Krieg and K. Mohseni, Synthetic Jets: Fundamentals and Applications, ch. Application of Zero-Net Mass-Flux Actuators for Propulsion: Biology and Engineering, pp329-355, ISBN 9781439868102, CRC Press, 2014

Dr. Adam DeVoria

Hydrodynamics of Micro-flows

Digital fluid dynamics is defined as the creation and manipulation of discrete packets of fluid, such as droplets. When the physical length scales are at the micro-scale, the advantages of employing discrete droplets for applications become increasingly apparent, as surface tension forces dominate allowing for less energetic actuation methods. This experimental research is primarily concerned with understanding the flow inside micro-droplets and how it is affected by parameters such as droplet aspect ratio, Reynolds number, and contact angle.

Low-aspect-ratio wing aerodynamics

This research focuses on investigating the unique aerodynamics and flow-structure interactions of low-aspect-ratio wings. These wings are able to affect reattached flow at high angles of attack, which allows for continued lift generation at these incidences. The downwash induced by the tip vortex flow is crucial in maintaining the reattached flow. Thus the unsteady interaction of the tip vortices with other flow structures, such as the leading-edge shear layer, is very important to the understanding of how to maintain stable flight.

References:
  • A.C. DeVoria and K. Mohseni, Droplets in an axisymmetric microtube: effects of aspect ratio and fluid interfaces, Physics of Fluids, 27(1), 012002, 2015
  • A.C. DeVoria and K. Mohseni, On the mechanism of high-incidence lift generation for steadily translating low-aspect-ratio wings, Journal of Fluid Mechanics, 2017

Dr. Bahman Aboulhasanzadeh

Development of Observable Methods for Computational Fluid Dynamics

For the past four decades, Computational Fluid Dynamics community has been developing a variety of methods to compute flows involving material interfaces (multiphase/multi-fluid flow), sharp flow variations (i.e. shocks), and turbulence. While the challenges in these categories of problems look different, they are all the result of limited resolution (Observability Limit) in calculations. By deriving governing equations with the assumption of limited resolution (Observable Set of Governing Equations), we are able to provide a unified framework for correctly computing the material interface, shock, and turbulence.


Graduate Students

Joseph Thalakkottor

Department of Mechanical & Aerospace Engineering
Boundary condition at multiphase contact line

Interface are ubiquitous in nature. The most common boundary condition to define tangential momentum transfer across an interface is the no-slip boundary condition. Although this has been remarkably successful in reproducing the characteristics of many types of flow, it breaksdowns for problems usch as spreading of a droplet, corner flow and extrusion of ploymer melts. Since the breakdown occurs at molecular sclaes, my research focuses on using molecular dynamics simulations to study this breakdown and develop a universal boundary condition for velcoity at the interface. Recent research has dealt with the studying the effect of unsteady flow on slip at the wall in a single phase fluid using molecular dynamic simulations. The left figure shows molecular dynamic simulation of oscillatory Couette flow and the right figure shows the hysteresis observed when slip velocity is plotted against shear rate of fluid.

References:
  • J.J. Thalakkottor and K. Mohseni, Stress dependent slip boundary condition for single and two phase fluid flow on a substrate, 43rd AIAA Aerospace Science Meeting, Kissimmee, FL, 5 - 9 Jan, 2015
  • J.J. Thalakkottor and K. Mohseni, Analysis of Boundary Slip in a Flow with an Oscillating Wall, Physical Review E., 87, 033018, 2013.

Peter Zhang

Department of Mechanical & Aerospace Engineering
Characterization of Digitized Heat Transfer (DHT) and multiphase contact line singularities

My research is primarily focused on the effects of discontinuities and singularities observed in continuum fluid dynamics. One portion of my research has been concentrated on the effects of fluid interfaces in Digitized Heat Transfer (DHT). Unlike conventional single phase cooling systems, DHT utilizes discrete microdroplets to remove excess heat. The second portion of my research focuses on modeling the triple contact line singularity using the Stokes equations and applying the results to continuum numerical simulations and theoretical predictions of contact line force.

References:
  • P. Zhang and K. Mohseni, Numerical investigations of digitized heat transfer, ASME 10th International Conference on Nanochannels, Microchannels, and Minichannels Conference (ICNMM), Puerto Rico, July 8-12, 2012.
  • P. Zhang and K. Mohseni. Numerical and experimental investigation of heat transfer within the first circulation length of a digitized flow. In Proceedings of the Semiconductor Thermal Measurement, Modeling, and Management Symposium (SEMI-Therm), San Jose, California, USA, March 17-21 2013. IEEE.

Zhuoyuan Song

Department of Mechanical & Aerospace Engineering
Cooperative localization and robot swarm collaboration

This study focuses on cooperative localization methods for autonomous vehicles when the GPS is not easily accessible and the vehicle dynamics is dominated by strong background flow fields. In non-uniform vector fields, path-independent, background vector field based global localization methods are developed to improve the dead-reckoning location estimation (Left). A cooperative localization hierarchy can further improve the overall localization performance in a vehicle swarm through range and frequency limited intra-vehicle measurements and communication (Right).

References:
  • Z. Song and K. Mohseni, Hierarchical underwater localization in dominating background flow fields, IEEE/RSJ Int. Conf. on Intelligent Robots and Systems (IROS 2013) , 3356-3361. Tokyo, Japan, 3-8 November 2013.

Richard O'Donnell

Department of Mechanical & Aerospace Engineering
Applications of Micro Aerial Vehicles

Recent investigations into the flight mechanics of Micro Aerial Vehicles (MAVs) have shown new stability modes that must be incorporated in Low Aspect Ratio (LAR) vehicle design.Using a regime of wind tunnel testing, flow visualization and flight validation I am working to develop an understanding the flight mechanics of MAVs. The understanding of the vehicle class will allow designs to be generated for use in varying applications without the mission specific empirical data currently required in MAV design. I hope this work will ultimately lead to MAVs used to collect data in severe weather systems such as hurricanes.


Matthew Silic

Department of Mechanical & Aerospace Engineering
Control of UAVs

My research focuses on the design and implementation of low-resource autopilots for UAVs, with an emphasis on novel control schemes and collaborative control.


Thomas Linehan

Department of Mechanical & Aerospace Engineering
Aerodynamics and stability of low-aspect-ratio winged fliers

My research draws connections between the fluid dynamics and stability of low-aspect-ratio vehicles. Currently, my focus is on asymmetric flight at incidence angles involving separated flow in which vorticity no longer stays bound to the wing. The consequence of this flow-field is that the aerodynamics and stability properties of the wing become highly non-linear in ways not captured by current modeling strategies.

My recent work has drawn the connection between the reattachment of the leading-edge shear layer in side-slip to non-linear roll moment generation or "roll stall" on low-aspect-ratio rectangular wings. At low to moderate lift coefficients, stabilizing roll moments increase linearly with lift due to the spatial asymmetries of the tip vortices and the non-uniform reattachment of the leading-edge shear layer. For a sufficiently low-aspect-ratio rectangular wing, the strength of the tip vortices increases sufficiently to reattach the leading-edge shear layer on the leeward wing thereby reducing the span-load asymmetries and yielding roll stall at an angle of attack of increasing lift.

Publications:
  • T. Linehan and K. Mohseni, Effect of leading-edge flow reattachment on the lateral static stability of low-aspect-ratio rectangular wings, Physical Review Fluids, submitted,
  • T. Linehan and K. Mohseni, Aerodynamics and lateral stability of low-aspect-ratio wings with dihedral at low Reynolds numbers, 54th AIAA Aerospace Sciences Meeting, AIAA paper 2016-1063, San Diego, CA, 4-8 January 2016.
  • T. Linehan, M. Shields and K. Mohseni, Development, characterization, and validation of a four axis wind tunnel positioning system, AIAA 52nd Aerospace Sciences Meeting, AIAA 2014-1308, National Harbor, Maryland, 13-17 January, 2014.

Andrew Bingler

Department of Electrical & Computer Engineering
Design of Autopilot Hardware

My work includes the design, development, and maintenance of the hardware used for the data collection, control, and telemetry of Micro Aerial Vehicles (MAVs). This hardware is also expandable, allowing it to be modified for use with other UAVs and vehicles.


Kevin Nelson

Department of Electrical & Computer Engineering
Bioinspired multimodel; fish lateral line sensory system

My research focuses on finding a general theory for ideal sensor placement to detect a distributed actuation. One application is to the artificial lateral line we implement for sensing and control in our autonomous underwater vehicle. Experimentally, I have been assisting with the test setup to validate the artificial lateral line.


Zheng Ren

Department of Mechanical & Aerospace Engineering
Lateral Line Modeling

Fish possess a mechanosensory lateral line system, which responds to the motion of the surrounding water relative to the fish's skin. The basic sensing unit of the two is the fish's hair cell. Such hair cells will deflect as the result of oncoming flow, thus allowing for detection. The hair cells located on the fish's skin (superficial neuromasts) respond to changes in external flow velocity, while the hair cells buried in a canal (canal neuromasts) along the fish's body respond to changes in external flow acceleration. This research is to seek for interpretation on the fish's ability of hydrodynamic imaging through its lateral line system.

The fish's lateral line canal was modeled to investigate its response to an external flow field. The results showed that the main characteristics of a vortex street are encoded in the flow distribution along the lateral line canal, and thus are accessible to the fish. In the real environment, the stimuli to the lateral line are more complex and thus could be hard to model. To this end, a CFD code is being developed, which is capable of computing flow field with complex-geometry-objects.

References:
  • Z. Ren and K. Mohseni, A Hybrid Pseudo-spectral Immersed-Boundary Method for Appli- cations to Aquatic Locomotion, 42nd AIAA Fluid Dynamics Conference, New Orleans, LA, 25-28 June 2012.

Yujendra Mitikiri

Department of Mechanical & Aerospace Engineering
Autonomous micro aerial vehicle

Majid Allahyari

Department of Mechanical & Aerospace Engineering
Application of Observable Methods to large scale simulation

Nicholas Sholl

Department of Mechanical & Aerospace Engineering
Soft robotics

Austin Moss

Department of Mechanical & Aerospace Engineering
Soft robotics and soft composite mechanics


Alumni