SOME RESEARCH FOCUS

 

                    

 

ferrofluid manipulation                                   magnetic fluid instability 

 

The primary focus of my research is the investigation of microscopic and macroscopic models of particulate systems, particularly those with direct physical applications, including: neutrally-buoyant and sedimenting suspensions, emulsions, granular materials, magnetic suspensions, fluidized beds and colloidal systems. The general themes of my research are: Micro-Hydrodynamics, Micro-Mechanics and Rheology of Complex Fluids, Fluctuations and Hydrodynamic Dispersion in Suspensions, Stability of Fluidized Beds, Drag Reduction in Flows, Bubble Dynamics, Perturbation Methods in Fluid Mechanics, Hydrodynamic of Magnetic Fluids, Stochastic Processes in Mechanical Science.

 

 

 

 

Pendent drop tensiometer - interfacial tension between liquid-liquid

 

 

 

 

Laboratory of Microhydrodynamics and Rheology - Micro-Rheo

 

 


 

 

Magneto-rheological fluids consist of suspensions of colloidal particles. Each particle contains many tiny, randomly oriented magnetic grains that can be oriented into chains by an externally applied magnetic field. These chains may further coalesce into larger-scale structures in the suspension, thereby dramatically increasing the viscosity of the suspension. This increase, however, may be totally reversed when magnetic field is turned off.

 

 

 

 

Very viscous fluid versus water

 

 

 

  magneto-rheological suspension - formation of particle agglomerates due do dipolar interactions

 

 

 

suspension of rough non-Brownian particles                                            oil-water  emulsion   

 

 

figpggabi.jpgbancadapggab.jpg

 

 

Vorticity dynamics in a gravitational vortex turbine in the presence of polymeric additives.  Team: Gabriel Santos (undergraduate student of Mechanical Engineering), Igor Dal Osto (Ph.D student in Mehanical Sciences), Prof. Francisco Ricardo (advisor). This project is relevant  in water treatment plant (Final Project CAESB/UnB). 

 

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ABOUT PROF. FRANCISCO R. CUNHA

 
                                      Rheological characterization  of complex fluids
 
FRC is a Professor of Fluid Mechanics in the Department of Mechanical Engineering at the University of Brasília. He is also a researcher of CNPq- Brazil.  His current research interests include: rheology of complex fluids;  hydrodynamic of magnetic fluids, non-Newtonian fluid dynamics, microhydrodynamics of active and passive particles in suspensions; and mechanics of mobile suspensions in general. His group focuses on developing mathematical and computational modeling tools with experimental investigations, that is highly interdisciplinary. This Professor was the pioneer and founder of the area of Microhydrodynamics and Rheology of Complex Fluids (e.g. magnetic suspensions, emulsions, elastic fluids) at the University of Brasília - Brazil. He has  supervised and guided several undergraduate and graduate students who are currently researching, advising and (or) working  in that area at UnB itself and at other institutions , including companies and industries in Brazil and abroad.
 
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 Graduate Students working in the LAB of Microhydrodynamics and Rheology - VORTEX/ENM/FT/UnB
 
 
Education and Formation
 

Post Doctoral Fellowship.  
 
Applied Math., University of California in Santa Barbara - USA, 2013-2013
 
Research topic: Mathematical Models for Magnetic Fluids

 

Research Collaboration with Prof. Hector D. Ceniceros

 

 

Post Doctoral Fellowship.

 

Chemical Engineering, Yale University, USA, 1998-2000

 

Research topic: Rheology of emulsion flows

 

Research advisor: Prof. Michael Loewenberg

 

 

Ph.D.

 

 

Applied Mathematics, University of Cambridge, UK, 1992-1995,

 

Robinson College - DAMTP - Department of Applied Mathematics and Theoretical Physics. Complex

 

Fluid Group - Microhydrodynamics - (G.K. Batchelor, E.J. Hinch and J.M Rallison)

 

Thesis title: Hydrodynamic dispersion in suspensions

 

Advisor: Prof. John Hinch, FRS

 

M.Sc.

 

 

Mechanical Sciences, University of Brasília, Brazil, 1987-1989


Dissertation title: Nonlinear mechanisms in fluidized beds.


Advisor: Prof. Antônio F. Parentes Fortes


 

B.S.

 

Mechanical Engineering, University of Brasília, Brazil, 1981-1986

 

 

Plataform Lattes-CNPq - Link: FRC Lattes

 


Academic Google -
Link: FRC Citations

 

 

WebGroup System-CNPq - Link: Group VORTEX  

 

 

Fluid Mechanics Videos by VORTEX Group


Video 1:
Instability of a Magnetic Fluid , by Cunha, F.R. & Abade, G.C., 2002 (This video has over 46.000 views on YouTube !)

Video 2:
The amazing self-locomotion of nematodes. See also PARTT II: Microhydrodynamics of Living Suspensions. These videos have been made during the current investigations of my Ph.D student Sara Malvar (2015-current).

Video 3:
Microhydrodynamics of a single drop , by Cunha, F.R. & Dias, N.J., 2013

Video 4:
A Model of Magnetic Separation Oil-Water , by Cunha, F.R. & Sobral, Y.D., 2004

Video 5:
Thermo-Magnetic Convection , by Gontijo, R.G. & Cunha, F.R., 2011. (Presented in the 6th Internacional Conference on Surfaces, Coatings and Nano-Structured Material -NANOMAT Conference - Krakow - Poland - 2011).

Video 6:
SUP - Stand up Paddle Fluid Mechanics (Hydrostatic and Dynamic - drag and lift) .

Video 7:
Talk of Prof. Hinch on the Flow of Elastic Liquids , (Opening talk of COBEM2007-Brazil)


 

Résumé - FRC 



Professor Francisco Ricardo Cunha received the diploma in Mechanical Engineering from the Department of Mechanical Engineering, University of Brasília, Brazil, in 1986. In 1989, he received a M.S. degree in Mechanical Science from the University of Brasília, Brazil. Then at the Department of Applied Mathematics and Theoretical Physics of University of Cambridge - UK, he was conferred, in 1995, a Ph.D. degree in Fluid Mechanics of Hydrodynamic Dispersion in Suspension Flows. He did a Postdoctoral work at Yale University (1998-2000), where he was also a visiting Associate Professor of the Chemical Engineering Department, and also a Postdoctoral program at University of California in Santa Barbara - UCSB-USA (2013). He joined the University of Brasília in 1995, and is currently Professor of Fluid Mechanics and Applied Mathematics and a Researcher (PQ)  of the National Council for Scientific and Technological Development – CNPq – Brazil since 1996. He is a CNPq's researcher level PQ - 1, since 2000. Prof. Cunha’s current research interests are in Microhydrodynamics, Micro-Mechanics, Rheology of Complex Fluids and Hydrodynamic of Magnetic Fluids. Editor-in-Chief- of Journal of Brazilian Society Mechanical Science and Engineering (2015-2019). Prof. Cunha has published several scientific articles in indexed Journal of high impact in his area as: Physics of Fluids, J. of Magnetism and Magnetic Materials, Physica A, Journal of Fluid Mechanics, Journal of Physics – Condensed Matter, Journal of Non-Newtonian Fluid Mechanics, J. of Fluids Engineering, Journal of Engineering Mathematics, Biomicrofluids-APS, Magnetohydrodynamics, Powder Technology, Probabilistic Engineering Mechanics, Computational and Applied Mathematics, Computer Methods in Appl. Mechanics and Engineering. This Professor was the pioneer and founder of the area of Microhydrodynamics and Rheology of Complex Fluids (e.g. magnetic suspensions, emulsions, elastic fluids) at the University of Brasília - Brazil. He has  supervised and guided several undergraduate and graduate students  who are currently researching, advising and (or) working  in that area at UnB itself and at other institutions , including companies and industries in Brazil and abroad. He also has supervised PhD, masters and undergraduate students currently. He has more than  1500 citations in high-impact scientific journals, resulting in an IH=21 and I10=43  (font: Google Schoolar's base). In Scopus's base he has a number of citations greater than  900 ones leading to an IH=15His theory on hydrodynamic diffusion in suspension is largely used for modelling particle or cell's migration  in blood flow. 

 
LABORATÓRIO DE MICROHIDRODINÂMICA E REOLOGIA
 
MICRO-RHEO - VORTEX/ENM/FT - UnB
 
(in Portuguese)