Vortex - Professor Francisco Ricardo Cunha, Ph.D

I am the scientist leader of the Fluid Mechanics of Complex Flows Group and the Microhydrodynamics and Rheology LAB at University of Brasilia. My 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. My research is highly interdisciplinary.  

LINK: A real magnetic emulsion composed of polar micro droplets (volume fraction=1%). The fluid is strongly anisotropic already em time=0 when an external magnetic field is applied. Formation of long chains. Indeed a quite complex fluid! (MFS Aleixo Filho, I.D. Pereira & FR Cunha - 2024 - in preparation).

SUPERVISION

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. I have 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 industry in Brazil and abroad. Most of the scientific publications listed below involves results of thesis, dissertations, final year project and scientific initiation research developed with my graduate and undergraduate students at University of Brasilia - ENM - VORTEX. I have highly valorized publishing with my supervised students.

SELECTED PUBLICATIONS

- F. Henrique & F. R. Cunha, Dispersion and particle pressure in sedimenting suspensions with hydordynamic interactions and finite particle inertia, 27p, 2024. (Submitted).

- C. O. Vieira, F.R. Cunha, Y.D. Sobral. Steady state regimes in lid driven cavity flows of magnetic fluids in the presence of an external magnetic field, 19p, 2024 (Submitted).

- F. R. Cunha & L.A.S. Inácio, A theoretical study on the bulk viscosity in a compressible flow of an eletrically conducting gas in the presence of magnetoacoustic waves, Physics of Fluids, 36 (4), 046124 , 2024. (doi: 10.1063/5.0201632).

- I. D. Pereira & F. R. Cunha, Rheological response of ferrofluids undergoing unsteady shear flows in the presence of a magnetic field, Physics of Fluids, 35/11, 112008-1/16, (16p), 2023.

- F. R. Cunha, Y. Z. Sinzato & I. D. Pereira, An experimental investigation on the magnetoviscous effect and shear rate-dependent viscosity of a magnetic suspension under longitudinal and transverse magnetic fields. Physics of Fluids, 34, 093314, 2022.

- G . A. Roure & F. R. Cunha, Modeling of unidiretional blood flow in microvessels with effect of shear-induced dispersion and particle migration. Applied Mathematics and Mechanics - Springer, 43(10), 1585-1600, 2022.

- Y. G. Irilan & F. R. Cunha, Experimental and theoretical studies of the fluid elasticity on the motion of macroscopic models of active helical swimmers. Physics of Fluids, 34, 053103, 2022.

- P. Z. S. Paz, F. R. Cunha & Y. D. Sobral, A note on the stability of plane parallel flows of magnetic fluids under the presence of external magnetic fields. Applied Mathematics and Mechanics - Springer , 43, 295-310, 2022.

- Y. Z. Sinzato & F. R. Cunha, Capillary flow of magnetic fluids with effect of hydrodynamic dispersion. Physics of Fluids, 33, 10, 102006, 2021, doi.org/10.1063/5.0067715.

- S. Malvar & F. R. Cunha, A theoretical model for studying the nonlinear viscoelastic response of an active fluid undergoing oscillatory shear. Physics of Fluids, 33, 091903, 2021, doi.org/10.1063/5.0062870.

- F. R. Cunha & A. P. Rosa, Effect of particle dipolar interactions on the viscoelastic response of dilute ferrofluids undergoing oscillatory shear. Physics of Fluids, 33 (9) 2021, 092004.

- G. A. Roure & F. R. Cunha, On the magnetization of a dilute suspension in a uniform magnetic field: influence of dipolar and hydrodynamic particle interactions. Journal of Magnetism and Magnetic Materials, 513, 167082, 2020.

- L.H.P da Cunha, I. Siqueira, F.R. Cunha & T.F. Oliveira, Effects of external magnetic fields on the rheology and magnetization of dilute emulsions of ferrofluid droplets in shear flows. Physics of Fluids , 32/7, 073306, 2020.

- Y. Z. Sinzato & F. R. Cunha, Modeling and experiments of capillary flow of non-symmetric magnetic fluids under uniform field. Journal of Magnetism and Magnetic Materials , 508, 166867, 2020.

- I. D. Perreira & F.R. Cunha, Rheological response in shear flows of a thermosensitive elastic liquid in the presence of some additivies. Rheologica Acta - Springer, 2020, 59, 307-316.

- A.P. Rosa & F.R. Cunha, The Influence of Dipolar Particle Interactions on the Magnetization and the Rotational Viscosity of Ferrofluids, Physics of Fluids, 31/5, 052006 17p., 2019.

- A. B. Guimarães, F.R. Cunha & R. G. Gontijo, The influence of hydrodynamic effects on the complex susceptibility response of magnetic fluids undergoing oscillatory fields: new insights for magnetic hyperthermia. Physics of Fluids - APS, 32/1, 012008, 2020.

- A. P. Rosa & F. R. Cunha, Shear rate dependence of viscosity and normal stress differences in ferrofluids. Journal of Magnetism and Magnetic Materials, vol. 499, 166184, 2020.

- J. A. C. Modesto, F. R. Cunha, Y. D. Sobral, Aggregation patterns in systems composed of few magnetic particles. Journal of Magnetism and Magnetic Materials, 512, 166664, 2020.

- S. Malvar, B. S. Carmo & F.R, Cunha, Rheology of a nematic active suspension undergoing oscillatory shear and step strain flows. Rheologica Acta - Springer, 58(11), 771-779, 2019.

- Y.D. Sinzato & F.R. Cunha, Stability analysis of an interface between immiscible liquids in Hele-Shaw flow in the presence of a magnetic field, Applied Mathematical Modelling, 75, 572-588, 2019.

- F.R. Cunha & T.F. Oliveira, A study on the flow of moderate and high viscosity ratio emulsion through a cylindrical tube , Rheologica Acta - Springer, Vol 58, 63-77, 2019.

- G.A. Roure & F.R. Cunha, Hydrodynamic dispersion and aggregation induced by shear in non-Brownian magnetic suspensions, Physics of Fluids, 30(12), 122002 (9p.), 2018.

- S. Malvar, R.G. Gontijo & F.R. Cunha, Nonlinear Motion of an Oscillating Bubble Immersed in a Magnetic Fluid, Journal of Engineering Mathematics , Vol 108/1, 143-170, 2018.

- R.G. Gontijo & F.R. Cunha, Numerical simulations of magnetic suspensions with hydrodynamic and dipole-dipole magnetic interactions, Physics of Fluids , Vol 29 , 062004 (21p), 2017.

- A.P. Rosa, G.C. Abade & F.R. Cunha, Computer Simulations of Equilibrium Magnetization and Microstructure in Magnetic Fluids, Physics of Fluids, Vol 29/6 , 092006 (13p), 2017.

-Y. Z. Sinzato, N.J. Dias & F.R. Cunha, An experimental investigation of the interfacial tension between liquid-liquid mixtures in the presence of surfactants, Experimental Thermal and Fluid Science , Vol 85C, 370-378, 2017.

- R.G. Gontijo, S. Malvar, Y.D. Sobral & F.R. Cunha, The influence of a magnetic field on the mechanical behavior of a fluid interface, Meccanica, Vol 52/6 , 1309-1327, 2017.

- S. Malvar, R.G. Gontijo, B.S. Carmo and F.R. Cunha, On the Kinematics-Wave Motion of Living Particles in Suspension, Biomicrofluidics, Vol 11, 044112-1 a 044112-16, 2017.

- A.P. Rosa, F.R. Cunha & H.D. Ceniceros, On Minimal Energy Dipole Moment Distributions in Regular Polygonal Agglomerates, Journal of Magnetism and Magnetic Materials, Vol 421, 269-282, 2017.

- I. R. Siqueira, R. B. Rebouças, T. F. Oliveira & F. R. Cunha, A New Mesh Relaxation Approach and Automatic Time-Step Control Method for Boundary Integral Simulations of a Viscous Drop, International Journal for Numerical Methods in Fluids, Vol 84, 221-238, 2017.

- F.R. Cunha, A.P. Rosa & N.J. Dias, Rheology of a Very Dilute Magnetic Suspension with Micro-Structures of Nanoparticles, Journal of Magnetism and Magnetic Materials, Vol 397C , 266-274, 2016.

- R.G. Gontijo, S. Malvar & F.R. Cunha, Magnetic particulate suspensions from the perspective of a dynamical system, Powder Technology, Vol 297, 165-182, 2016.

- A.P. Rosa, R.G. Gontijo & F.R. Cunha, Laminar pipe flow with drag reduction induced by a magnetic field gradient, Applied Mathematical Modeling, Vol 40, 3907-3918, 2016.

- T.F. Oliveira & F.R. Cunha, Emulsion Rheology for Steady and Oscillatory Shear Flows at Moderate and High Viscosity Ratio, Rheologica Acta, Vol 54, 951-971, 2015.

- R.G. Gontijo & F.R. Cunha, Dynamic numerical simulations of magnetically interacting suspensions in creeping flow, Powder Technology, Vol 279, 146-165, 2015.

- F.R. Cunha, R.G. Gontijo & Y.D. Sobral, Symmetry breaking of particle trajectories due to magnetic interactions in a dilute suspension, Journal of Magnetism and Magnetic Materials, Vol 326, 240-250, 2013.

- F.R. Cunha & D.L. Albernaz , Oscillatory motion of a spherical bubble in a non-Newtonian fluid, Journal of Non-Newtonian Fluid Mechanics, Vol 191, 35-44, 2013.

- D.L. Albernaz & F.R. Cunha, Unsteady Motion of a Spherical Bubble in a Complex Fluid: Mathematical Modelling and Simulation, Applied Mathematical Modelling, Vol 37, 8972-8984, 2013.

- F.R. Cunha, Y.D. Sobral & R.G. Gontijo, Stabilization of concentration waves in fluidized beds of magnetic particles, Powder Technology, Vol 24 (1C), 219-229, 2013.

- T.F. Oliveira & F.R. Cunha, A theoretical description of a dilute emulsion of very viscous drops undergoing unsteady simple shear, Journal of Fluids Engineering - Transitions of the ASME (AIP - American Institute of Physics), Vol 133 (10), 101208 (8p), 2011.

- F.R. Cunha & H.L.G. Couto, On the influence of the hydrodynamic interactions on the aggregation rate of magnetic spheres in a dilute suspension, Journal of Magnetism and Magnetic Materials, Vol 323/1 , 77-82, 2011.

- D.L. Albernaz & F.R. Cunha, Bubble dynamics in a Maxwell fluid with extensional viscosity, Mechanics Research Communications, Vol 38/3, 255, 2011.

- R.V.V Lopes, L.F.B Osório, I.S Resk, M.J.A Sales, M.L. Santos, F.R. Cunha, Physicochemical and rheological properties of polyol from passion fruit oil, European Journal of Lipid Science and Technology, Vol 112 , 1253-1262, 2010.

- F.R. Cunha & H.L. Couto, Transverse Gradient Diffusion in a Polydisperse Dilute Suspension of Magnetic Spheres During Sedimentation, J. Phys: Condens. Matter, Vol 20, 204129, 2008.

- F.R. Cunha & H.L.G. Couto, A New Boundary Integral Formulation to Describe Three-Dimensional Motions of Interfaces Between Magnetic Fluids, Applied Mathematics and Computation, Vol 199/1, 70, 2008.

- G.C. Abade & F.R. Cunha, Computer Simulation of Particle Aggregates During Sedimentation, Computer Methods in Applied Mechanics and Engineering, Vol 196, 4597, 2007.

- Y.D. Sobral, T.F. Oliveira & F.R. Cunha, On the Unsteady Forces During the Motion of a Sedimenting Particle , Powder Technology, Vol 178, 131, 2007.

- F.R. Cunha, H.L.G. Couto, N.B. Marcelino, A Study on Magnetic Convection in a narrow Rectangular Cavity, Magnetohydrodynamics, Vol 43/4, 421-428, 2007.

- F.R. Cunha & M. Andreotti, A Study of the Effect of Polymer Solution in Promoting Friction Reduction in Turbulent Channel Flow , Journal of Fluids Engineering - Transitions of the ASME (AIP - American Institute of Physics), Vol 129, 491, 2006.

- S.C.A Absi, G.C. Carvalho & F.R. Cunha, A Statistical Approach for Monitoring Stochastic Welding Processes, Journal of Materials Processing Technology, Vol 175, 4, 2006.

- F.R. Cunha & Y.D. Sobral, Characterization of the Physical Parameters in a Process of Magnetic Separation and Pressure Driven Flows of a Magnetic Fluid in a Cylindrical Tube, Physica A, Vol 343, 36, 2004.

- FR Cunha, MH Almeida & M Loewenberg, Direct Numerical Simulations of Emulsion Flows, J. Braz. Soc. Mech. Sci , Vol 25, 30, 2003.

- YD Sobral & FR Cunha, A Stability Analysis of a Magnetic Fluidized Bed, Journal of Magnetism and Magnetic Materials , Vol 258, 464, 2003.

- F.R. Cunha & M. Loewenberg, A Study of Emulsion Expansion by a Boundary Integral Method, Mechanics Research Comm., Vol 30/6, 639, 2003.

- F.R. Cunha, A.J. Sousa & P.C. Morais, The Dynamic Behaviour of a Collapsing Bubble in a Magnetic field, Journal of Magnetism and Magnetic Materials, Vol 252, 271, 2002.

- F.R. Cunha, G.C. Abade, A.J. Sousa & E.J. Hinch, Modelling and Direct Simulation of Velocity Fluctuations and Particle-Velocity Correlations in Sedimentation, Journal of Fluids Engineering - Transitions of the ASME, Vol 124, 4, 957, 2002.

- F.R. Cunha, A.J. Sousa & E.J. Hinch, Numerical Simulation of Velocity Fluctuations and Dispersion of Sedimenting Particles, Chem. Engn. Comm, Vol 189/9, 1105-1129, 2002.

- F.R. Cunha & E.J. Hinch, Shear induced dispersion in a dilute suspension of rough spheres, Journal of Fluid Mechanics, Vol 309, 211, 1996.

TEACHING

CURRENT LECTURES ON ADVANCED FLUID MECHANICS

"Happy the one who transfers what he knows and learns what he teaches."

(C. Coralina)h

Continuum Mechanics course

Multiphase Flow course

Last lecture of the Microhydrodynamics course : Slender body theory (1/2023). Dense course, but the students do like it! Some comments of currents, former students and Colleagues (in Portuguese). Students of the Microhydrodynamics course - PCMEC- ENM-UnB- lectures 1/2023. (i) "Não sei se vou ter a oportunidade de fazer outra matéria com o senhor, então aproveito para agradecer por todas as aulas e pela atenção em todos os cursos que fiz. Tenho certeza que suas aulas foram um dos motivos (talvez o maior) para que o mestrado valesse a pena. E também guardo e sempre vou guardar comigo um grande apreço por sua pessoa" (Raysa Gomes). (ii) "Muito legal!!! E imagino que deve ter sido um curso incrível mesmo. Foi a melhor matéria que eu fiz" (Gesse Roure). (iii) "Que bacana, professor! Foi meu curso favorito na UnB"! (Filipe Evangelista). (iv) "Tenho certeza que deve ter sido fantástico esse curso, bro! Parabéns pela dedicação e entusiasmo com que você conduz seus cursos e pesquisas, irmão! A UnB ganha muito com você ali dentro!" (Rafael Gabler).

Multiphase flow course - last lecture of the semester 2/2022 - Porous media -

Microhydrodynamics course

"Há pessoas que marcam a nossa vida, que despertam algo especial em nós, que abrem nossos olhos de modo irreversível e transformam a nossa maneira de ver o mundo. Você foi uma dessas pessoas! Os seus ensinamentos foram muito além dos conteúdos do currículo. Tive aprendizados importantes para a vida. A sua missão vai muito além da missão de um professor, você é um verdadeiro mestre. Você soube despertar a minha admiração de um modo único, e se tornou uma inspiração para mim. Muito obrigado pela sua dedicação, paciência e carinho ao lecionar. Só posso agradecer por ter feito parte de minha trajetória em 2023, e tenha certeza de que tudo o que aprendi, vou levar por toda a minha vida. Mestre, toda a minha gratidão e carinho! Que seu 2024 seja marcado por muitas conquistas e realização de sonhos! Que tenhas muita saúde e que a felicidade impere em todos os âmbitos da sua vida! Um grande abraço! Feliz ano novo" (Igor Dal Osto Pererira - dez/2023)!

Magnetohydrodynamics course

Microhydrodynamics course

(v) "Sensacional prof!!! Parabéns por compartilhar seus conhecimentos a essa geração futura... Um profissional de excelência" (anônimo). (vi)" O curso mais importante que eu fiz no doutorado!" (Yves-Gamard Irilan). (vii) "Parabéns por mais um semestre deste excelente curso, professor! Tenho ótimas memórias da época que cursei, e as aulas até hoje me ajudam muito com a pesquisa! "(Yuri Sinzato), (viii) "Esse curso é incrível mesmo! Eu tenho meus cadernos até hoje... E do curso de Fluidos Não-Newtonianos também." (Hugo Couto), (ix) "Aproveito para agradecer pelo semestre. Como já havia dito, essa foi a disciplina que mais gostei de todas que fiz. Só a parte teórica já seria suficiente para dizer isso, a teoria dessa disciplina é muito bonita (muda muito a visão que temos sobre a Física por trás dos fenômenos através de uma matemática bem bonita), mas além disso, aprendi muito com os exercícios e trabalhos numéricos, que certamente melhoraram ainda mais a disciplina" (aluno Leonardo Inácio - 1/2023). (x) " Parabéns, Francisco, isso é realmente o trabalho que importa. Teu trabalho é realmente um trabalho social e educador e sobretudo transformador. " (Sadek Alfaro), (xi) "Bom dia Francisco! Fantástico! Keep moving forward!" (Paulo Morais).

Non-Newtonain Fluid Dynamics course

Lectures on Continuum Mechanics by prof. FR Cunha - VORTEX/ENM- University of Brasília, 2/2016.

Visit of John Hinch (my PhD supervison from DAMTP-Cambridge-UK) to University of Brasilia (April/2023). In this opportunity John received an honorur of Professor Honoris Causa from UnB - Brazil

Lectures on Microhydrodynamics - Brownian Motion - August - 2023

UnB/FT/ENM/Vortex/Micro-Rheo

Prof. Francisco Ricardo Cunha, BSc., MSc., Ph.D

BSc and MSc (University of Brasília - Brazil),

Ph.D (DAMTP-U. of Cambridge - UK)

Postdoctoral (Yale University - USA and U. of California in Santa Barbara - UCSB-USA)

Leader of the VORTEX - Fluid Mechanics of Complex Flows Research Group/CNPq

Coordinator of Microhydrodynamics & Rheology LAB - MICRO-RHEO/VORTEX/ENM/FT/UnB

Address

University of Brasília - Dep. of Mechanical Engineering - FT

Programa de Pós-Graduação em Ciências Mecânicas - PCMEC

Fluid Mechanics of Complex Flows - Research Group - VORTEX

Campus Universitário - Asa Norte, Brasília-DF, BRAZIL, 70910-900

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