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					                      Fluid Dynamics Research Center
                                           About Us
        The Fluid Dynamics Research Center (FDRC) is a division of the Mechanical, Materials
and Aerospace Engineering Department (MMAE) of the Illinois Institute of Technology (IIT).
The FDRC was established in 1985 to continue the tradition of research in fluid dynamics begun
by the pioneering work of Dr. Mark Morkovin and Dr. Andrew Fejer carried out at Illinois
Institute of Technology in the 1960s. Faculty and researchers have established a tradition of
excellence in research, particularly through the use of advanced experimental and computational
techniques, in areas such as unsteady aerodynamics, “fluid – structure” interaction, turbulence,
hydrodynamic stability, and aeroacoustics.
        In 1986 under the guidance of Dr. Hassan Nagib, the Fluid Dynamics Research Center
was chosen as one of three National Centers of Excellence by the US Air Force Office of
Scientific Research. The FDRC maintains several wind tunnels and water channels including the
National Diagnostic Facility, which is a large wind tunnel with very high quality flow. In recent
years, the FDRC has established expertise in computational fluid dynamics to complement its
strengths in experimental research, and it has partnered increasingly with industry to augment its
traditional base of funding through US Department of Defense agencies.

                                            Mission
1. Develop New Technology based on creative application of fluid dynamics principles:
      • Aerospace applications
      • Biomedical applications
      • Homeland security
2. Advance and Disseminate Fundamental Knowledge in fluid dynamics with experimental,
   computational, and analytical approaches to problem solving
3. Educate Students in state-of-the-art numerical and experimental techniques
      • Impact graduate education
      • Impact undergraduate education

                                           Sponsors
•   Engineering and Physical Sciences Research Council, UK
•   European Community and Universities
•   IIT Pritzker Institute of Biomedical Science and Engineering
•   Lindbergh Foundation
•   NASA Space Grant
•   National Science Foundation
•   The Boeing Company
•   The University of Chicago
•   The University of Melbourne, Australia
•   US Air Force Office of Scientific Research
•   US Army Research Office
•   US Department of Energy
•   US Office of Naval Research


                                                1
                                    Areas of Activities
1. Fundamentals
    • Dr. Cassel – application of optimal control theory to unsteady separation
    • Dr. Nagib – high Reynolds number turbulence; three-dimensional and separated flows;
       modeling of complex turbulent and separated flows
    • Dr. Raman – experiments and analysis to understand compressible flow
    • Dr. Rempfer & Dr. Wark – developing new theories and experiments to improve
       prediction capabilities related to contaminant dispersion
2. Aerospace Applications
    • Dr. Cassel – conducting fundamental studies of vortex surface interactions and unsteady
       boundary-layer separation
    • Dr. Nagib – enhancing forces on aerodynamic surfaces, with application to high-lift and
       reduced drag, for tilt-rotor aircraft, advanced concept STOL vehicles, and bluff bodies
    • Dr. Raman – actuators for aircraft nozzle and cavity flow control
    • Dr. Rempfer & Dr. Wark – development and optimization of wind power generators for
       tall buildings
    • Dr. Williams – using active flow control to extract energy from unsteady flows, to
       reduce the effects of wind gusts on wings, and to enhance aircraft maneuverability by
       modifying the leading edge vortex
3. Biomedical Applications
    • Dr. Cassel – computational modeling of cephalic arch hemodynamics in dialysis
       patients with arteriovenous fistulas
    • Dr. Raman – micro-shock actuators for biomedical applications
    • Dr. Rempfer – fluid dynamics of magnetic nanoparticles in blood flow
    • Dr. Williams – using fluidic oscillators to design more accurate / less expensive
       equipment for the detection of chronic pulmonary disease

                                           People
Coordinator:                                      Master’s Degree Candidates:
   • Elena Magnus                                    • Gregoire Boulard
                                                     • Seth Buntain
Ph.D. Candidates:                                    • Kedar Chaudhari
   • Michael Boghosian                               • Kristofer Dressler
   • Michael Dominik                                 • Rakesh Ramachandran
   • Richard Duncan                                  • Brian Rojas
   • Sriharsha Kandala                               • Paul Rozier
   • Wesley Kerstens                                 • Seth Thomas
   • Paritosh Mokhasi                                • Denis Vasilescu
   • Bruno Monnier
   • Vien Quach                                   Undergraduate Students:
   • Chetan Sardesai                                 • Cari Hesser
   • Shekhar Sarpotdar                               • Galina Shpuntova
   • Ricardo Vinuesa Motilva                         • Stefan Stevanovic


                                              2
                                            Faculty

                                       Kevin W. Cassel
                  Associate Professor of Mechanical & Aerospace Engineering




                                       Vortex shedding due to
                                        cephalic arch stenosis



Field of specialty: Computational fluid dynamics addressing problems in biofluids, unsteady
aerodynamics and cryogenic fluid flow and heat transfer, fundamental aspects of unsteady
separation, boundary-layer flows, boundary-layer instabilities, application of optimal control
theory to fluid flows, and buoyancy-driven flows with heat generation



                                      Hassan M. Nagib
      John T. Rettaliata Distinguished Professor of Mechanical & Aerospace Engineering




                                           Variation of surface
                                           friction and log-law
                                      parameters with pressure
                                     gradient along a turbulent
                                                 boundary layer


Field of specialty: Fluid mechanics, particularly the areas of hydrodynamic stability and
transition, applied turbulence, unsteady flows, separated flows, wind engineering and
atmospheric diffusion, aeroacoustics, and convection heat transfer, with emphasis on
management and control of flows and high Reynolds number wall-bounded turbulence




                                                 3
                                      Ganesh G. Raman
                  Associate Professor of Mechanical & Aerospace Engineering




                                      Phase averaged measurements
                                            of the first Rossiter tone
                                             produced by a shallow
                                                    cavity at M = 0.6


Field of specialty: Fluid mechanics and aeroacoustics with emphasis on high speed flows and
the noise produced by flow interactions, including fundamental experimental investigations of
the acoustics, fluid flow physics of supersonic jets, turbulent shear layers, and flow control



                                       Dietmar Rempfer
                  Associate Professor of Mechanical & Aerospace Engineering




                                           The classical fourth-order
                                              Runge-Kutta method:
                                              accuracy and stability




Field of specialty: Fluid mechanics, especially theoretical studies of transitional and turbulent
shear flows in open systems, numerical fluid mechanics, mathematics of Navier-Stokes
equations, coherent structures in turbulent flows, and nonlinear dynamical systems




                                                  4
                                      Candace E. Wark
                       Professor of Mechanical & Aerospace Engineering




                                       One of several planes, within
                                       roughness array, over which
                                          stereo PIV measurements
                                                           are made




Field of specialty: Fluid mechanics, with particular emphasis on experimental studies of wall-
bounded turbulent flows and unsteady-separated flows; current research projects include the
structure of urban-type boundary layers and the unsteady-separated corner flows in
turbomachinery applications



                                      David R. Williams
                      Professor of Mechanical & Aerospace Engineering,
                                       Director FDRC




                                      Dynamic stall vortex induced
                                         by tunnel oscillation: thin
                                           airfoil, (2 Hz, 12 % U∞)
                                               oscillation, α = 15°,
                                                             no yaw


Field of specialty: Experimental fluid mechanics and aerodynamics with emphasis on active
flow control, control of acoustic tones in cavities, airfoil performance enhancement, rotating
machinery, fluidic oscillators for flow metering, and biomedical applications




                                                 5
                                  Research Projects 2009

Applications of Active Flow Control to Unsteady Flow
Funded by: AFOSR
Professor David Williams

This research focuses on the application of modern active flow control techniques to unsteady
aerodynamics and fluid flows. In particular, with support from the Air Force Office of Scientific
Research, the group is exploring methods to enhance the maneuverability of small unmanned and
micro-air vehicles. The ability to reduce the unsteady forces in gusting flows and the ability to
execute bird-like perch landings maneuvers is also of interest. Fundamental studies into the
energy exchange mechanisms between gusting winds and micro air vehicles is also being
examined as a way of increasing the range and endurance. In addition to unsteady aerodynamics,
new flow meters with very low pressure losses and large range of application are being
developed. Research into improving the performance of axial flow compressors used on aircraft
engines is also underway.


Sub-Optimal and Optimal Control of Unsteady Boundary-Layer Separation
Funded by: Engineering and Physical Sciences Research Council (EPSRC), UK
Professor Kevin Cassel

A two-dimensional channel with localized suction from the upper surface is considered as a
framework within which to consider sub-optimal and optimal control of an unsteady separating
boundary layer. A quasi-steady (sub-optimal) approach is adopted in which the control input is
optimized at each time as the unsteady flow evolves. Two cost functionals are implemented and
compared; they both use a boundary-based performance measure that minimizes the difference
between the wall shear stress and a target distribution corresponding to the unseparated boundary
layer. The two control mechanisms considered, with corresponding penalty functions in the
respective cost functionals, are a domain-based control, involving a body force throughout the
boundary layer, and a boundary-based control, involving the normal wall velocity. The sub-
optimal control results will be compared with a fully nonlinear optimal control approach using
the unsteady boundary-layer equations as the governing state equations.


A Computational Model of Cephalic Arch Hemodynamics in Arterial Venous Fistulas
Funded by: University of Chicago
Professor Kevin Cassel

A computational fluid dynamics (CFD) model is being developed of the hemodynamics within
the cephalic arch after insertion of an arterial venous fistula (AVF). This model will allow for
determination of the representative geometric and flow features within the cephalic arch that may
contribute to development of cephalic arch stenosis (CAS) in dialysis patients after fistula
creation, which dramatically alters the hemodynamics in the cephalic arch. An accurate in vivo




                                               6
model of hemodynamics will provide a data platform on which to improve the overall design of
fistula implants based on a fundamental understanding of the factors that influence their patency.


Level-Set Method for Simulation of Two-Phase Flow in Micro- and Macro-Scale Heat
Transport Devices
Funded by: NASA
Professor Kevin Cassel and Professor Jamal Yagoobi

A fundamental understanding of the electrically driven dielectric liquid film flow in two-phase
micro- and macro-scale heat transport devices is sought. The level-set method is incorporated
with computational fluid dynamics (CFD) to investigate various electrode geometries and
optimize their performance for two-phase EHD conduction pumping phenomena. The numerical
data will be compared with experimental that are being obtained in parallel. This study will
improve our understanding of the interaction between electric fields with heat transfer and mass
transport. For example, in microdevices, the interaction between the double layer and
heterocharge layers will be elucidated allowing for design of devices with improved efficiency.


High Reynolds Number Wall-Bounded Turbulence
Professor Hassan Nagib

Nearly all currently used commercial codes for computation of flow in applications including
aeronautics, energy generating machines, and weather prediction rely on the von Kármán
constant. We examine the overlap parameters of the logarithmic law for available experimental
and computational date from turbulent boundary layer, pipe, and channel flows, over wide ranges
of Reynolds numbers, using composite profiles fitted to the mean velocity. This reveals that
boundary layers with streamwise pressure gradients, and pipe and channel flows display von
Kármán coefficients that are not universal. Therefore, we conclude that the von Kármán constant
exhibits dependence on not only the pressure gradient but also the wall-bounded flow geometry,
thereby raising fundamental questions regarding turbulence flow theory and modeling for all
wall-bounded flows. Along the way, we also examine various alternatives to the log law,
including various forms of power laws, and conclude that there is no reason to abandon a
perfectly coherent and successful leading order model (the von Kármán-Millikan-Rotta-Clauser
log law) for descriptions which have problems modeling available data, and in some cases
promise a final asymptotic state we will probably never be able to verify.


Flow Control of Separation and Circulation and their Impact on Improved Aerodynamic
Performance
Professor Hassan Nagib

Zero-net mass flux oscillatory jets introduced from span wise slots at various locations on the
upper surface of steady and oscillating airfoil models are shown to be effective in controlling lift,
moment and drag coefficients over the range of Mach numbers over 0.4. This control is
demonstrated over a wide range of mean angles of attack from light to deep stall conditions on



                                                  7
several airfoil cross sections with and without flaps. With non-dimensional frequency and
amplitude of the forcing unchanged, we find comparable modifications of the aerodynamic
coefficients throughout this Mach number range. Near the higher end of this Mach number range,
local supercritical conditions are experienced near the leading edge and shocks are present. Even
in these cases the flow control was found to be effective with slot positions near the location of
the shock. Therefore, it appears that this active flow control technique is only limited by the
ability to generate the adequate forcing conditions at the higher Mach numbers required for
applications such as rotorcraft, and aircraft requiring high lift for short takeoff and landing or
controllable drag for rapid maneuverability.


Jet and Cavity Noise Suppression Using High Frequency Excitation & Ultrasonic
Actuators Funded by: AFOSR and Lindbergh Foundation
Professor Ganesh Raman

This project explores new methods to reduce the aeroacoustics caused by aircraft, including
noise from jets and cavities using high frequency actuators. Instead of the current passive flow
control techniques, like lobed nozzles and chevrons, which are unable to adapt to changing
working loads of the aircraft, there are plans to develop an active flow control actuator that can
be turned on during take-off and turned off during cruising time, to retain maximum fuel
economy. In addition, the high frequency fluidic flow control actuators have no moving parts,
making the operation simple and highly reliable. A high bandwidth powered resonance tube
actuator that is potentially useful in noise and flow control applications has also been developed
and characterized, under funding from the United States Air Force.


Integration of Wind Turbines with Tall Buildings
Funded by: US Department of Energy and IIT ERIF
Professor Dietmar Rempfer

This research is developing design concepts for energy-sustainable in order to develop practical
methods for the integration of wind power plants into the design of tall buildings (“sky
scrapers”). The intention is to size the power plants such that they can provide at least enough
power to make the building energy autonomous on average, possibly even providing some
excess energy that can be sold and fed into the public power grid, while at the same time
optimizing the design subject to a number of disparate requirements.


Optimization of Vertical and Shrouded Wind Turbines
Funded by: US Department of Energy
Professor Dietmar Rempfer

This project is interested in optimizing the power output of wind turbines, focusing on two
particularly important issues:




                                                 8
•   Finding optimal ducts that can be used in conjunction with either horizontal- or vertical-axis
    machines (HAWTS or VAWTS), which will allow the wind turbines to produce energy in
    excess of the Betz limit. Computational aerodynamics in conjunction with optimization
    algorithms are being used for this work.

•   While HAWTs are well developed at the current technological state of the art, and can
    produce power output close to the theoretical limit, VAWTs are much less understood from a
    fundamental aerodynamics point of view. In particular, typical power coefficients of VAWTs
    are lower by a factor of about two than the ones for HAWTs. Detailed investigations of the
    aerodynamics of such turbines are therefore being performed, followed by an optimization of
    their power output with the goal of achieving performance similar to the one of HAWTs.


Development of Spectral Element Code for Unsteady Geometries
Professor Dietmar Rempfer

This project has as its goal the development of a highly accurate computational fluid mechanics
code that will be based on a spectral element approach. In contrast to existing codes of this type,
we will allow grids that vary in time, and that include portions of the grid that are in relative
motion with respect to other grid regions. This will allow us to perform accurate simulations of
flow through rotating machinery as well as, ultimately, flow through or around deformable
geometries. For high Reynolds numbers we will also include the option of sub-grid scale
modeling via a scale-independent LES (Large Eddy Simulation) approach.


Remote Flow Sensing of Complex Systems: Steps towards Contaminant Dispersion
Modeling at the Urban Scale
Funded by: Illinois Consortium of the NASA Space Grant
Professor Candace Wark

Contaminant dispersion at the urban level has become a major concern in recent decades.
Pollutant and toxic chemical releases, intentional or not, need to be monitored and detected
quickly. Prediction of the flow field in an urban area based on a few measurements is essential in
order to provide the best possible response. To improve on existing solutions, a combination of
various measurement tools (Hot Wire Anemometry, Stereoscopic Particle Imagery, Static
Pressure measurements via an array of microphones & Laser Doppler Velocimetry) is being used
to study the airflow around wall mounted obstacles in a turbulent boundary layer. To make the
problem more tractable, Proper Orthogonal Decomposition is used to lower the dimensionality of
the problem in projecting the velocity field onto a set of optimal basis functions and associated
coefficients. The challenge lies then in finding the best way to correlate the various information
to construct accurate dynamical models, hybrid measurement models (direct or indirect) and
state space models that will provide robust remote flow sensing capability.




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                                    Facilities




Andrew Fejer Unsteady Wind Tunnel                Anechoic Acoustic Test Chamber




     Axial Flow Compressor                           Computational Facilities




      High-Speed Jet Facility                         Impinging Jet Facility



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Mark V. Morkovin Wind Tunnel              National Diagnostic Facility




   Supersonic Wind Tunnel                    Water Channel Facility




                                    Address
                                    Fluid Dynamics Research Center at MMAE
                                    10 West 32nd Street, E1 Bldg., Suite 209
                                    Illinois Institute of Technology
                                    Chicago, IL 60616

                                    Phone: (312) 567-3188
                                    Fax: (312) 567-3173
                                    http://www.fdrc.iit.edu




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