Research Interests

I seek to model and simulate the behavior of complex fluid flow, such as turbulent flows, and their interaction with solid structures. Relevant applications are: forced isotropic turbulence, fully developed channel flows, cardiovascular blood flow (including fluid-structure interaction, arterial-wall modeling, drug delivery simulations, and non-Newtonian effects of blood), and flow in porous media. My focus is on computational modeling of these phenomena, with sound theoretical support. These applications demand efficient, accurate and robust solution strategies, which I develop and implement in massively parallel computing platforms (in collaboration with the Professor Hughes's Group and Texas Advanced Computing Center staff).

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Animations and snapshots

Most of these animations were done in collaboration with from Greg P. Johnson and Karla Vega from TACC. (Use mplayer to view the movies.)

Cahn-Hilliard Phase-Field Model

Work in collaboration with H. Gomez Diaz, Y. Bazilevs and T.J.R. Hughes

Phase separation simulation: these simulations show the importance of the initial mean concentration. A lower value (c_mean=0.63) leads to a very interconnected evolution, while when a phase dominates (c_mean=0.75) nucleation occurs.

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Bypass transition to turbulence of a laminar boundary layer

The visualization software utilized has been developed in collaboration with Greg P. Johnson from TACC. If you are interested in using it please contact us.

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Residual-based turbulence modeling

Work in collaboration with Y. Bazilevs and T.J.R. Hughes

Forced isotropic turbulence

The visualization software utilized has been developed in collaboration with Greg P. Johnson from TACC. If you are interested in using it please contact us.

Vorticity isosurfaces and particle motion following streamlines:
Vortex stretching

Fully developed turbulent channel flow

The visualization software utilized has been developed in collaboration with Greg P. Johnson from TACC. If you are interested in using it please contact us.

Streamwise-velocity isosurfaces and particle motion following streamlines:

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Cardiovascular simulations (Including fluid-structure interaction and drug delivery.)

Work in collaboration with Y. Bazilevs, N. Brasher, T.J.R. Hughes, T.E. Tezduyar, and Y. Zhang

The visualization software utilized is Paraview.

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Publications

Links point to submitted preprints, which are archived as ICES Reports.

Refereed Archival Journals

  1. N. Brasher, V.M. Calo, Y. Bazilevs, and T.J.R. Hughes, "A multiphysics model for blood flow and drug transport with application to patient-specific coronary artery flow," in preparation, 2008.
  2. M.C. Hsu, Y. Bazilevs, V.M. Calo, T.E. Tezduyar, and T.J.R. Hughes, "Improving stability of multiscale formulations of fluid flow at small time steps," in preparation, 2008.
  3. Y. Bazilevs, C. Michler, V.M. Calo, and T.J.R. Hughes, "Turbulence without tears: residual-based VMS, weak boundary conditions, isogeometric analysis and wall-bounded flows," Computer Methods in Applied Mechanics and Engineering, submitted, 2008.
  4. Y. Bazilevs, V.M. Calo, T.J.R. Hughes, and Y. Zhang, "A fully-integrated approach to fluid-structure interaction," in preparation, 2008.
  5. D. Pardo, C. Torres-Verdin, M. J. Nam, M. Paszynski, and V.M. Calo, "Fourier Series Expansion in a Non-Orthogonal System of Coordinates for Simulation of 3D AC Borehole Resistivity Measurements," Computer Methods in Applied Mechanics and Engineering, accepted for publication, 2007.
  6. H. Gomez, V.M. Calo, Y. Bazilevs, and T.J.R. Hughes, "Isogeometric analysis of the Cahn-Hilliard phase-field model," Computer Methods in Applied Mechanics and Engineering, submitted, 2007.
  7. T. Elguedj, Y. Bazilevs, V. M. Calo, and T. J. R. Hughes, "B-bar and F-bar Projection Methods for Nearly Incompressible Linear and Nonlinear Elasticity and Plasticity using Higher-order NURBS Elements," Computer Methods in Applied Mechanics and Engineering, accepted for publication, 2008.
  8. D. Pardo, V.M. Calo, C. Torres-Verdin, and M. J. Nam, "Fourier Series Expansion in a Non-Orthogonal System of Coordinates for Simulation of 3D Borehole Resistivity Measurements. Part I: DC," Computer Methods in Applied Mechanics and Engineering, accepted for publication, 2007.
  9. Y. Bazilevs, V.M. Calo, J.A. Cottrell, T.J.R. Hughes, A. Reali, and G. Scovazzi. "Variational multiscale residual-based turbulence modeling for large eddy simulation of incompressible flows," Computer Methods in Applied Mechanics and Engineering, 2007. doi: 10.1016/j.cma.2007.07.016.
  10. I. Akkerman, Y. Bazilevs, V. M. Calo, T. J. R. Hughes, and S. Hulshoff. "The role of continuity in residual-based variational multiscale modeling of turbulence," Computational Mechanics , 2007. doi: 10.1007/s00466-007-0193-7.
  11. Y. Bazilevs, V.M. Calo, T.E. Tezduyar and T.J.R. Hughes, "YZbeta discontinuity capturing for advection-dominated processes with application to arterial drug delivery," International Journal for Numerical Methods in Fluids, 54:593-608, 2007.
  12. M. Paszynski, D. Pardo, C. Torres-Verdin, L. Demkowicz and V.M. Calo, "A Nested Dissection Parallel Multi-Frontal Direct Solver for hp Finite Element Method," Parallel Computing, accepted for publication, 2008.
  13. Y. Bazilevs, C. Michler, V.M. Calo and T.J.R. Hughes, "Weak Dirichlet boundary conditions for wall-bounded turbulent flows," Computer Methods in Applied Mechanics and Engineering, 2007. doi: 10.1016/j.cma.2007.06.026.
  14. Y. Bazilevs, V.M. Calo, Y. Zhang and T.J.R. Hughes, "Isogeometric Fluid-structure Interaction Analysis with Applications to Arterial Blood Flow," Computational Mechanics, Vol. 38, Nos. 4-5, pp. 310-322, September 2006.

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Book Chapters

  1. H. Gomez, V.M. Calo, and T.J.R. Hughes, "Isogeometric Analysis of Phase-field Models: Application to the Cahn-Hilliard Equation", In New Computational Challenges in Materials, Structures, and Fluids, Springer, 2008.
  2. Y. Bazilevs, V.M. Calo, J.A. Cottrell, T.J.R. Hughes, A. Reali, and G. Scovazzi. "Variational multiscale residual-driven turbulence modeling for large eddy simulation of incompressible flow." In A. Ibrahimbegovic, F. Dias, H. Matthies, and P. Wriggers, editors, Computational Methods for Solids and Fluids, 2007.
  3. Y. Bazilevs, V.M. Calo, Y. Zhang, and T.J.R. Hughes, "A fully integrated isogeometric approach to fluid-structure interaction." In M. Papadrakakis, E. Onate, and B. Schrefler, editors, Proceedings of International Conference on Computational Methods for Coupled Problems in Science and Engineering, Coupled Problems 2007. CIMNE, 2007.
  4. Y. Bazilevs, V.M. Calo, J.A. Cottrell, T.J.R. Hughes, and Y. Zhang, "Isogeometric modeling and analysis for naval ship structures." In M. Papadrakakis, E. Onate, and B. Schrefler, editors, Computational Methods in Marine Engineering, Marine 2007. CIMNE, 2007.
  5. T.J.R. Hughes, V.M. Calo and G. Scovazzi, "Variational and Multiscale Methods in Turbulence," pp. 153-163, Mechanics of the 21st Century (eds. W. Gutkowski and T.A. Kowaleski), Springer, Dordrecht, The Netherlands, 2005.

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Refereed Conference Proceedings

  1. V.M. Calo, H. Gomez, Y. Bazilevs, G.P. Johnson, and T.J.R. Hughes, "Simulation of Engineering Applications Using Isogeometric Analysis," TeraGrid 08, Las Vegas, Nevada, June 9-13, 2008.
  2. Y. Bazilevs, V.M. Calo, T.J.R. Hughes, and Y. Zhang, "Modeling and computation of patient-specific vascular fluid-structure interaction using Isogeometric Analysis," in Proc. of the 6th International Conference on Computation of Shell and Spatial Structures IASS-IACM 2008: ``Spanning Nano to Mega'', J.F. Abel and J.R. Cooke (eds.), 28-31 May, 2008, Cornell University, Ithaca, NY, USA.
  3. A. Gonzalez, F. Bombardelli, V.M. Calo and Y. Nino, "Simulation of particle motion close to a rigid wall," Proceedings of Environmental & Water Resources Institute (EWRI), American Society of Civil Engineers (ASCE), Tampa, Florida, May 15-19, 2007.
  4. Y. Bazilevs, Y. Zhang, V.M. Calo, S. Goswami, C. Bajaj, and T.J.R. Hughes, "Isogeometric analysis of blood flow: a NURBS-based approach," CompIMAGE 2006 - Computational Modelling of Objects Represented in Images: fundamentals, methods and applications, Coimbra, Portugal, October 20-21, 2006.
  5. G.P. Johnson, K. Gaither and V.M. Calo, "Visualizing Turbulent Flow," Proceedings of the 15th IEEE Visualization 2004 (VIS'04), Austin, Texas, pp. 598.22, October 10-15, 2004.
  6. T.J.R. Hughes, V.M. Calo and G. Scovazzi, "Variational and Multiscale Methods in Turbulence," Proceedings of the 21st International Congress of Theoretical and Applied Mechanics, Kluwer Academic Publishers, 2004.
  7. T.J.R. Hughes, A. Oberai and V.M. Calo, "Multiscale methods in turbulence," JUSIS 2002, Proceedings of Sixth Japan-US International Symposium on Flow Simulation and Modeling (ed. Hiroshi Kanayama), Fukuoka, Japan, May 2002.
  8. A. Sfriso and V.M. Calo, "Application of finite strains kinematics to the constitutive equations of frictional materials. Part I (in Spanish)," Proceedings of the Encounter of Argentinean Geotechnicians 96, pp. VI.5-1, Cordoba, Cordoba, Argentina, 1996.
  9. V.M. Calo and A. Sfriso, "Application of finite strains kinematics to the constitutive equations of frictional materials. Part II (in Spanish)," Proceedings of the Encounter of Argentinean Geotechnicians 96, pp. VI.5-11, Cordoba, Cordoba, Argentina, 1996.

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Technical Reports

  1. G.P. Johnson, V.M. Calo and K. Gaither, "Interactive Visualization and Analysis of Transitional Flow."
  2. V.M. Calo and T.J.R. Hughes, "Large Eddy Simulations of Bypass Transition by the Variational Multiscale Method," Final Research Report for NAG2-1604, NASA Ames Research Center Grant No.: N05-4116, 2004.
  3. G. N. Wells, T.J.R. Hughes, V.M. Calo, G. Scovazzi and Y. Bazilevs,"Multiscale large eddy simulation of bypass transition," Final Research Report, NASA Ames Research Center Grant No.: NCC 2-5457, 2002.

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Ph.D. Thesis

"Residual-based multiscale turbulence modeling: finite volume simulations of bypass transition" (pdf)

Variational multiscale concepts are used to construct subgrid-scale models for Large-Eddy Simulation (LES) of turbulence. The basic idea of this framework is to introduce, a priori, a decomposition of the solution into coarse and fine scales. The coarse scales are identified with the numerical approximation, while the fine scales are identified with the subgrid scales and need to be modeled. A residual-based fine-scale approximation is proposed by extending to the nonlinear realm algebraic approximations of the local Green's function. These approximations, based on the Stabilized Methods theory, may be thought of as the modeling component of the proposed approach. This new modeling concept is very different from the classical LES modeling ideas, which are dominated by the addition of ad hoc eddy viscosities.

These newer variational multiscale ideas, and the older variants, have been implemented in a finite volume program that has enjoyed widespread use in turbulence simulations. The difficult problem of simulating the bypass transition of a boundary layer is examined from the point of view of the variational multiscale method and classical LES. The aim was to solve this problem as an LES and demonstrate the efficacy of the new residual-based modeling ideas in the process. Independent of the LES method, it was found that in order to accurately simulate bypass transition, the decay of input homogeneous, isotropic, free-stream turbulence must be the same for all meshes. A procedure was developed that enabled simulation of consistent energy decay with the range of meshes considered. The formulation is outlined and numerical results are presented and compared to a conventional LES approach, DNS results and experimental data.

The new method performs as well as the state-of-the-art LES models and offers a promising new path for turbulence research in LES. However, it obviously needs further testing on a wider variety of flows and implementation in a variety of numerical frameworks before drawing definitive conclusions. The experience gained indicates that the particular numerical discretization method has an enormous impact upon the results, and its influence is often underestimated by practitioners evaluating models.

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Civil Engineer Thesis

"Stain-space plasticity: Application to frictional materials" (pdf)

Thesis is written in Spanish. Synthesis of contents is written in English.

In this work, the Plasticity Theory is applied to granular media, particularly to soils. The development of the Plasticity theory is done in strain space. This is due to the fact that the softening processes of the material may be represented as an extension of the formulation developed for hardening processes, the perfect plasticity being a transition between the two behaviors.

The classical results of soil mechanics are obtained in the frame of continuum mechanics assuming some of the usual hypotheses of the former.

The proposed Constitutive Theory is applied to a simple model based on the Critical State Theory. With this model some usual basic soil laboratory tests are simulated and good qualitative description of them is obtained.

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Students' Work

  1. Master Thesis of Nathan F. Brasher, Development of a Multiphysics Model for Blood Flow and Drug Transport with Application to Patient-Specific Coronary Artery Flow. Co-supervised with Thomas J.R. Hughes.

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In the Media

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Institute for Computational Engineering and Sciences
The University of Texas at Austin
201 East 24th Street, ACES 4.102
1 University Station, C0200
Austin, TX 78712-0027
off: (512) 232-7771
fax: (512) 232-7508
e-mail: victor@ices.utexas.edu

Last updated on May 6th, 2008.