Said Elghobashi                             

Professor

Department of Mechanical and Aerospace Engineering
University of California, Irvine
Irvine, CA 92697

EDUCATION:
M.Sc., University of Southern California (1971)
Ph.D., Imperial College, University of London (1974)
D.Sc., Imperial College, University of London (1999)

HONORS:
Member of the National Academy of Engineering
Fellow of the American Physical Society
Fellow of the American Association for the Advancement of Science
Fellow of the American Society of Mechanical Engineers
Visiting Fellow Cambridge University, England, 1999
DIC: Diploma of membership of Imperial College, 1974
British Science Research Council (SRC) Scholarship (1971-1974)

CONTACT:
E-mail: selghoba@uci.edu
Office: EG 4220
Phone: (949) 824-6131         

  

 

 

 

 

Research Objective

The main objective of my research is to understand some of the fundamental properties of turbulence using the method of direct numerical simulation (DNS). DNS of turbulent flows is the numerical solution of the exact, three-dimensional, time-dependent Navier-Stokes equations. The direct solution, via DNS, of these equations, which govern the motion of Newtonian fluids, eliminates the closure problem and its inevitable empiricism.

Due to the limited memory and speed of current and near-future supercomputers (even the massively parallel machines) it is not expected that DNS will be able to predict engineering flows in complex geometries (e.g. the flow over an airplane or inside a combustor) in the foreseeable future. However, DNS will remain the only numerical method that can provide new physical insights at all scales of turbulence in flows involving complex physical phenomena such as chemically-reacting or particle-laden turbulent flows. This distinct capability of DNS is simply due to the absence of empiricism. Furthermore, DNS has already provided excellent agreement with measurements in wind tunnels at comparable values of the microscale Reynolds number. As the capabilities of parallel computing expand, DNS will be more widely used in scientific studies of complex physical phenomena in simple geometries.

 

 

Selected Journal Papers

 

 

  • Wang, Y. and Elghobashi, S.      “On locating the obstruction in the upper airway via numerical simulation ",   

      Respiratory Physiology and Neurobiology,  Vol. 193,   pp.1-10 (2014).

  • Lucci, F., L'vov, V., Ferrante, A., Rosso, M. and Elghobashi, S.      “ Eulerian-Lagrangian bridge for the energy and dissipation spectra in isotropic turbulence ",   

      Theoretical and Computational Fluid Dynamics,  DOI: 10.1007/s00162-013-0310-5 (2013).

  • Cleckler, J., Elghobashi, S., and  Liu, F.   “ On the motion of inertial particles by sound waves ",   

      Physics of Fluids,  Vol. 24, 033301 (2012).

  • Lucci, F., Ferrante, A. and  Elghobashi, S. E.   “ Is Stokes number an appropriate indicator for turbulence modulation by particles of Taylor-length-scale size? ",   

      Physics of Fluids,  Vol. 23,   pp.25101-1-7 (2011).

  • Lucci, F., Ferrante, A. and  Elghobashi, S. E.   “Modulation of isotropic turbulence by particles of Taylor-lengthscale size ",   

      J. Fluid Mechanics,  Vol. 650, pp. 5-55   (2010).

  • Ferrante, A. and  Elghobashi, S. E.   “On the accuracy of the two-fluid formulation in DNS of bubble-laden turbulent boundary layers ",   

      Physics of Fluids,  Vol. 19, 045105, pp.1-8   (2007).

  • Ferrante, A. and  Elghobashi, S. E.   “ On the effects of microbubbles on the Taylor-Green vortex flow ",   

     J. Fluid Mechanics,  Vol.572, pp. 145-177   (2007).

  • Ferrante, A. and  Elghobashi, S. E.   “ Reynolds number effect on drag reduction in a bubble-laden spatially developing turbulent boundary layer ",   

     J. Fluid Mechanics,  Vol. 543, pp. 93-106   (2005).

  • Ferrante, A.,  Elghobashi, S. E., Adams, P., Valenciano, M. and Longmire, D.  “Evolution of  quasi-streamwise vortex tubes and wall streaks in a microbubble-laden turbulent boundary layer over a flat plate",   

Physics of Fluids,   Vol. 16., No. 9, pp. S2   (2004).

  • Ferrante, A. and  Elghobashi, S. E.   “ On the physical mechanisms of drag reduction in a spatially-developing
    turbulent boundary layer laden with microbubbles",   

     J. Fluid Mechanics,  Vol. 503, pp. 345-355 (2004).

  • Ferrante, A. and  Elghobashi, S. E.  “A robust method for generating inflow conditions for direct simulations of spatially-developing turbulent boundary layers",         

    J. Comp. Physics,  Vol. 198,  pp. 372-387 (2004).

  • Ferrante, A. and  Elghobashi, S. E.   “ On the physical mechanisms of two-way coupling in particle-laden isotropic turbulence ”,
    Physics of Fluids,  Vol. 15, pp. 315-329 (2003).
  • Ahmed, A.M. and  Elghobashi, S. E.   “ Direct numerical simulation of particle dispersion in homogeneous turbulent shear flows ”,               
    Physics of Fluids,  Vol. 13, pp.3346-3364 (2001).
  • Druzhinin, O.A. and  Elghobashi, S. E.   “ Direct numerical simulation of a three-dimensional spatially-developing bubble-laden mixing layer with two-way coupling”,               
    J. Fluid Mechanics,  Vol. 429, pp. 23-61 (2001).
  • Ahmed, A.M. and  Elghobashi, S. E.   “ On the mechanisms of modifying the structure of turbulent homogeneous shear flows by dispersed particles”,               
    Physics of Fluids,  Vol. 12, pp. 2906-2930 (2000).
  • Zhong, R. , Elghobashi, S. E. and Boratav, O.  “Surface topology of a  buoyant turbulent nonpremixed flame”,   

           Physics of Fluids,  Vol.  12, pp. 2091-2100 (2000).                                   

  • Elghobashi, S., Zhong, R. and Boratav, O. "Effects of gravity on turbulent nonpremixed flames",
    Physics of Fluids, Vol. 11, pp. 3123-3135 (1999).
  • Druzhinin, O.A., and Elghobashi, S.E.," A Lagrangian-Eulerian mapping solver for direct numerical simulation of a bubble-laden homogeneous turbulent shear flow using the two-fluid formulation",
    J. Comp. Physics, Vol. 154, pp. 174-196 (1999).
  • Druzhinin, O.A., and Elghobashi, S.E., "On the decay rate of isotropic turbulence laden with microparticles",
    Physics of Fluids, Vol. 11, pp. 602-610 (1999).
  • Boratav, O.N., Elghobashi, S.E. and Zhong, R., "On the alignment of strain, vorticity and scalar gradient in turbulent, buoyant, nonpremixed flames",
    Physics of Fluids, Vol. 10, pp. 2260-2267 (1998).
  • Kim, I.,Elghobashi, S. E., and Sirignano, W., "On the equation for spherical particle motion: effect of Reynolds and acceleration numbers",
    J. Fluid Mechanics, Vol. 367, pp. 221-253 (1998).
  • Druzhinin, O. and Elghobashi, S., "DNS of bubble-laden turbulent flows using the two-fluid formulation",
    Physics of Fluids, Vol. 10, pp. 685-697 (1998).
  • Kim, I.,Elghobashi, S. E., and Sirignano, W., "Unsteady flow interactions between a pair of advected vortex tubes and a rigid sphere",
    International J. Multiphase Flow, Vol. 23, pp. 1-23 (1997).
  • Boratav, O., Elghobashi, S. E., and Zhong, R., "On the alignment of the a-strain and vorticity in turbulent nonpremixed flames,"
    Physics of Fluids, Vol. 8, pp. 2251-2253 (1996).
  • Kim, I.,Elghobashi, S. E., and Sirignano, W., "Unsteady flow interactions between an advected cylindrical vortex tube and a spherical particle",
    J. Fluid Mechanics, Vol. 288, pp. 123-155 (1995).
  • Truesdell, G. C. and Elghobashi, S. E., "On the two-way interaction between homogeneous turbulence and dispersed solid particles; Part 2: particle dispersion,"
    Physics of Fluids, Vol. 6, pp. 1405-1407 (1994).
  • Elghobashi, S. E., "On Predicting Particle-Laden Turbulent Flows,"
    J. Applied Scientific Research, Vol. 52, 4, pp. 309-329 (1994).
  • Elghobashi, S. E., and Truesdell, G. C., " On the two-way interaction between homogeneous turbulence and dispersed solid particles ; Part 1 : turbulence modification",
    Physics of Fluids, Vol. A5, pp. 1790-1801 (1993).
  • Nomura, K. N., and Elghobashi, S. E. "The structure of inhomogeneous turbulence in variable density nonpremixed flames",
    Theoretical and Computational Fluid Dynamics, Vol. 5, pp. 153-176 (1993).
  • Kim, I.,Elghobashi, S. E., and Sirignano, W., "Three- dimensional flow over two spheres placed side by side",
    J. Fluid Mechanics, Vol. 246, pp. 465-488 (1993).
  • Nomura, K. N., and Elghobashi, S. E. "Mixing characteristics of an inhomogeneous scalar in isotropic and homogeneous sheared turbulence",
    Physics of Fluids, Vol. 4, pp. 606-625 (1992).
  • Elghobashi, S.E., and Truesdell, G.C., "Direct Simulation of Particle Dispersion in a Decaying Isotropic Turbulence",
    J. Fluid Mechanics, Vol. 242, pp. 655-700 1790-1801 (1992).
  • Gerz, T., Schumann, U. and Elghobashi, S. "Direct Simulation of Stably Stratified Homogeneous Turbulent shear Flows",
    J. Fluid Mechanics, Vol. 200, pp. 563-594 (1989).
  • Elghobashi, S. E., and Abou Arab, T.W., " Two-Equation Turbulence Model for Two-Phase Flows ",
    Physics of Fluids, Vol. 26, pp. 931-928 (1983).

 

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Last update: Dec 25, 2009