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Bruno Welfert

Associate Professor
Faculty, TEMPE Campus, Mailcode 1804
Biography

Bruno Welfert's research focuses on stability issues in numerical models arising in various engineering problems.

Welfert is currently investigating instabilities of fluid flows in (closed) cubic containers under various configurations (under rotation, temperature stratified,...) in order to understand the dynamics of unsteady flows and in particular their kinetic and helical (spin) properties. 

Welfert has recently investigated how certain numerical treatments of water flow across unsaturated soil layers can lead to nonphysical solutions. These problems can produce erroneous predictions of water infiltration profiles, and inadequate and costly geotechnical and building recommendations.

Welfert is also evaluating the impact of uncertainty in models of physical phenomena. For example soils are inhomogenous, with hydraulic properties not known precisely. Probabilistic models of these properties are useful to evaluate the consequences of this uncertainty on actual flow predictions. A fundamental challenge is to understand such mechanism using simple yet accurate stochastic models.

Education

Ph.D. University of California-San Diego 1990

 

Publications
  • A. Bharadwaj; S.L. Houston; W.N. Houston; B. Welfert; K.D. Walsh. Effect of soil replacement option on surface deflections for expansive clay profiles Advances in Unsaturated Soils. Proceedings of the 1st Pan-American Conference on Unsaturated Soils, PanAmUNSAT 2013 (2013).
  • Bradley R. Kuna; Kenneth D. Walsh; Sandra L. Houston; Claudia Zapata; Bruno Welfert. Full scale test of periodic irrigation infiltration in a cracked and intact clay slope. Geotechnical Special Publication (2013).
  • Bruno Welfert, Karel in't Hout. Unconditional stability of second-order ADI schemes applied to multi-dimensional diffusion equations with mixed derivative terms. Applied Numerical Mathematics (2009).
  • H. B. Dye, S. L. Houston and B. D. Welfert. Influence of Unsaturated Soil Properties Uncertainty on Moisture Flow Modeling. Geotechnical and Geological Engineering (2009).
  • K. Burrage, Z. Jackiewicz, B.D. Welfert. Spectral Approximation of Time Windows in the Solution of Dissipative Linear Differential Equations. Journal of Numerical Analysis, Industrial and Applied Mathematics (2009).
  • Bruno Welfert. On quadrature formulae based on derivative collocation. Applied Mathematics & Computation (2008).
  • Bruno Welfert, Zdzislaw Jackiewicz, Mahbubur Rahman. Numerical solution of a Fredholm integro-differential equation modelling -neural networks. Applied Mathematics & Computation (2008).
  • Bruno Welfert. Analysis of Iterated ADI-FDTD Schemes for Maxwell Curl Equations. Journal of Computational Physics (2007).
  • K in 't Hout, Bruno Welfert. Stability of ADI schemes applied to convection-diffusion equations with mixed derivative terms. Applied Numerical Mathematics (2007).
  • M Rahman, Z Jackiewicz, Bruno Welfert. Stochastic approximations of perturbed Fredholm Volterra integro-differential equation arising in mathematical neurosciences. Applied Mathematics and Computation (2006).
  • Z Jackiewicz, M Rahman, Bruno Welfert. Numerical solution of a Fredholm integro-differential equation modelling neural networks. Applied Numerical Mathematics (2006).
  • Welfert, Bruno, Lopez, J, Marques, F. Impact of noise on the onset of vortex breakdown. (2005).
  • J Jackiewicz, Bruno Welfert, B Zubik-Kowal. Spectral vs. pseudospectral solutions of the wave equation by relaxation. J. Sci. Comp (2004).
  • Z Jackiewicz, Bruno Welfert, B Zubik-Kowal. Spectral vs. pseudospectral solutions of the wave equation by relaxation methods. J. Scientific Computing (2004).
  • Kojouharov, H V (Author) ,Welfert, Bruno Denis (Author) . Generalized Nonstandard Numerical Methods for Nonlinear Advection-Diffusion-Reaction Equations: Lecture Notes in Computer Science 2907. Large-Scale Scientific Computing (2004).
  • H Kojouharov, Bruno Welfert. A nonstandard Euler scheme for y''+g(y)y'+f(y)y = 0. J. Comp. Appl. Math (2003).
  • M Spijker, S Tracogna, Bruno Welfert. About the Sharpness of the Stability Estimates in the Kreiss Matrix Theorem. Mathematics of Computation (2003).
  • Welfert, Bruno Denis. MATLAB Manual. (2003).
  • Welfert, Bruno Denis, Pothoven, Kenneth. MAPLE Manual. (2003).
  • A Gelb, J Jackiewicz, Bruno Welfert. Absorbing boundary conditions of the second order for the pseudospectral Chebyshev methods for wave propagation. J. Sci. Comp (2002).
  • J Jackiewicz, Bruno Welfert. Stability of Gauss-Radau pseudospectral approximations of the one-dimensional wave equation. J. Sci. Comp (2002).
  • H Kojouharov, Bruno Welfert. A New Numerical Approach for the Solution of Scalar Nonlinear Advection-Reaction Equations. Int. Journal of Applied Science & Computations (2001).
  • J Mead, R Renaut, Bruno Welfert. Stability of a Pivoting Strategy for Gaussian Elimination in Parallel. BIT (2001).
  • K Burrage, G Hertono, Zdzislaw Jackiewicz, Bruno Welfert. Acceleration of convergence of static and dynamic iterations. BIT (2001).
  • B Owren, Bruno Welfert. The Newton Iteration on Lie Groups. BIT (2000).
  • S Tracogna, Bruno Welfert. Two-Step Runge-Kutta Methods: Theory and Practice. BIT (2000).
  • Kojouharov, H, Welfert, Bruno. A new numerical approach for the solution of advection-reaction equations. Institute of Applied Science and Computations (2000).
Research Activity
Fall 2018
Course NumberCourse Title
MAT 420Scientific Computing
MAT 591Seminar
APM 792Research
APM 799Dissertation
Summer 2018
Course NumberCourse Title
MAT 275Modern Differential Equations
MAT 343Applied Linear Algebra
APM 792Research
APM 795Continuing Registration
Spring 2018
Course NumberCourse Title
MAT 266Calculus for Engineers II
MAT 343Applied Linear Algebra
MAT 495Undergraduate Research
MAT 591Seminar
APM 792Research
APM 799Dissertation
Fall 2017
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 420Scientific Computing
MAT 591Seminar
APM 792Research
APM 799Dissertation
Summer 2017
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 421Applied Computational Methods
APM 792Research
APM 795Continuing Registration
Spring 2017
Course NumberCourse Title
MAT 343Applied Linear Algebra
APM 520Adv Numerical Linear Algebra
MAT 591Seminar
APM 792Research
APM 799Dissertation
Fall 2016
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 420Scientific Computing
MAT 591Seminar
APM 792Research
APM 799Dissertation
Summer 2016
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 421Applied Computational Methods
APM 792Research
Spring 2016
Course NumberCourse Title
MAT 421Applied Computational Methods
MAT 499Individualized Instruction
APM 520Adv Numerical Linear Algebra
APM 792Research
APM 799Dissertation
Fall 2015
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 420Scientific Computing
APM 792Research
Summer 2015
Course NumberCourse Title
MAT 421Applied Computational Methods
APM 792Research
Spring 2015
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 492Honors Directed Study
APM 792Research
Fall 2014
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 420Scientific Computing
MAT 492Honors Directed Study
MAT 493Honors Thesis
MAT 494Special Topics
APM 792Research
Summer 2014
Course NumberCourse Title
MAT 421Applied Computational Methods
APM 792Research
Spring 2014
Course NumberCourse Title
MAT 343Applied Linear Algebra
MAT 492Honors Directed Study
APM 792Research
Presentations
  • Bruno Welfert, Juan Lopez & Stephanie Taylor. Complex dynamics in a stratified lid-driven cavity flow. 67th Annual Meeting of the APS Division of Fluid Dynamics, San Francisco (Nov 2014).
  • Bruno Welfert & Juan Lopez. Stability of stratified 2D cavity flow. 10th AIMS Conference on Dynamical Systems,Differential Equations and Applications, Madrid, Spain (Jul 2014).
  • J. Lopez & B. Welfert. Slow passage through resonance: the big picture. Joint Math Meeting, San Diego (Jan 2013).
  • B. Welfert. On Gauss Quadrature. Computational and applied ProSeminar (Mar 2010).
  • B. Welfert. Stability of parallel stationary ADI splittings for the 1D diffusion equation. Computational and Applied Math Proseminar (Sep 2008).
  • Welfert, Bruno, Lopez, Juan, Castro, Reynaldo. Reduction of Dynamical Systems Under Stochastic Parametric Forcing. SIAM Conference on Analysis of Partial Differential Equations (PD07) (Dec 2007).
  • Welfert, Bruno. On the Structure of the Spectrum of Alternate Direction Implicit Iteration Operators. COMPUTATIONAL AND APPLIED MATHEMATICS PROSEMINAR (Sep 2007).
  • Welfert, Bruno, Lopez, Juan, Castro, Reynaldo. Coherence Resonance Via Harmonic and Stochastic Parametric Forcing in Sir. SIAM Conference on Applications of Dynamical Systems (DS07) (May 2007).
  • Lopez, Juan, Marques, F, Welfert, Bruno. IMPACT OF NOISE ON THE ONSET OF VORTEX BREAKDOWN. Frontiers in Applied and Computational Mathematics (May 2006).
  • Castro, R, Lopez, J, Murillo, D, Welfert, Bruno. Stochastic Parametric Forcing in Hydrodynamics. Los Alamos/Arizona Days (Jan 2006).
  • Welfert, Bruno, Lopez, J, Marques, F. Impact of noise on the onset of vortex breakdown. 2005 58th Annual Meeting of the Division of Fluid Dynamics, American Physical Society (Nov 2005).
  • Welfert, Bruno, Lopez, J, Marques, F. Stochastic Parametric Forcing in Hydrodynamics. NISS/SAMSI Workshop on Collaborations in the Mathematical Geosciences (Oct 2005).
  • Welfert, Bruno. What is stiff order?. Colloquim (Jun 2004).
  • Jackiewicz, Z, Rahman, M, Welfert, Bruno. Numerical solution of a Fredholm intro-differential equation modelling neural networks. 3rd International Conference on the Numerical Solution of Volterra and Delay Equations (May 2004).
  • Lopez, J, Welfert, Bruno. Stochastic Navier-Stokes. NA day on Numerical Analysis and Geometric Integration (May 2004).
  • Welfert, Bruno. Stability of pseudospectral approximations of the one-dimensional wave equation. Conference on Scientific Computation (Jun 2002).
  • Welfert, Bruno. Trails & tribulations in establishing a new BS degree in Computational Mathematical Sciences at ASU. Excellence in Undergraduate Mathematics: Mathematics for the Non- traditional Major, American Mathematical Society-Mathematical Education Reform Workshop (May 2002).
Service
  • Personnel and Budget Committee, member (2009 - Present)
  • Abstract and Applied Analysis, reviewer (2013 - 2013)
  • Applied Numerical Mathematics, Reviewer (2013 - 2013)
  • BIT Numerical mathematics, reviewer (2013 - 2013)
  • International Journal of Nonlinear Sciences and Numerical Simulation, reviewer (2013 - 2013)
  • Applied Numerical Mathematics, Reviewer (2012 - 2012)
  • Numerical Algorithms, reviewer (2012 - 2012)
  • Applicable Analysis, Reviewer (2012 - 2012)
  • Applied Mathematical Analysis, Reviewer (2012 - 2012)
  • Acta Mathematica Scientia, reviewer (2011 - 2011)
  • Applied Mathematics and Computation, reviewer (2011 - 2011)
  • Applied Numerical Mathematics, reviewer (2011 - 2011)
  • Journal of Computational Finance, reviewer (2011 - 2011)
  • Numerical Algorithms, reviewer (2011 - 2011)
  • Applied Mathematics and Computation, reviewer (2011 - 2011)
  • Undergraduate committee, member (2010 - 2010)
  • Applied Numerical Mathematics, Reviewer (2010 - 2010)
  • Communications in Nonlinear Science & Numerical simulations, Reviewer (2010 - 2010)
  • Computer Physics communications, Reviewer (2010 - 2010)
  • Mathematical Modeling & Numerical Algorithms, Reviewer (2010 - 2010)
  • SIAM Journal on Scientific Computing, Reviewer (2010 - 2010)
  • Applied Numerical Mathematics, Reviewer (2009 - 2009)
  • BIT, Reviewer (2009 - 2009)
  • IEEE Transactions on Antennas and Propagation, Reviewer (2009 - 2009)
  • International Journal of computer mathematics, Reviewer (2009 - 2009)
  • Numerical Algorithms, reviewer (2009 - 2009)
  • Undergraduate Advisory Committee, chair (2006 - 2009)
  • Associate Chair for Undergraduate Programs, chair (2006 - 2009)
  • Applied Numerical Mathematics, Reviewer (2008 - 2008)
  • Computational and Applied Mathematics, reviewer (2008 - 2008)
  • IMA Journal of Numerical Analysis, reviewer (2008 - 2008)
  • Journal of Computational Physics, reviewer (2008 - 2008)
  • Numerical Algorithms, reviewer (2008 - 2008)
  • Undergraduate Programs, Department of Mathematics and Statistics, Associate Chair (2006 - 2006)
  • Calculus Oversight Committee, Department of Mathematics and Statistics, Member (2006 - 2006)
  • MGE@MSO Student Research Conference 06, Reviewer (2006 - 2006)
  • More Graduate Education at Mountain States Alliance and Western Alliance to Expand Student Opportunities, Tempe, AZ, Judge (2006 - 2006)
  • W. H. Freeman calculus focus group, San Francisco, Participant (2006 - 2006)
  • International Conference on Computational Science, reviewer (2005 - 2005)
  • Intel International Science and Engineering Fair, Grand Award Judge (2005 - 2005)
  • Intel International Science and Engineering Fair, Phoenix, Grand Award Judge (2005 - 2005)
  • Addison Wesley, reviewer (2004)
  • Applied Numerical Mathematics, reviewer (2004)
  • Journal of Fluid Mechanics, reviewer (2004)
  • SiNUM, reviewer (2004)
  • Addison-Wesley focus group, AMS annual meeting, Participant (2004 - 2004)
  • CLAS Curriculum committee, Member (1999 - 2003)
  • J. Computational and Applied Math, reviewer (2003)
  • J. Scientific Computing, reviewer (2003)
  • Nonliner Methods for PDEs, reviewer (2003)
  • Theoretical and Computational Fluid Dynamics, reviewer (2003)
  • examination committee, write/grade comprehensive examination for Master/Ph.D. students (2003)
  • Lecturer Evaluation Committee, Department of Mathematics and Statistics, Member (2001 - 2001)
  • Undergraduate Advisory Committee, Department of Mathematics & Statistics, Member (2000 - 2001)
  • Flow Technology, Consultant (2001 - 2001)
  • Skill Technologies Inc, Consultant (2000 - 2000)