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Howard Hu

Professor

Phone: 215.898.8504
Email: hhu@seas.upenn.edu
Office: 241 Towne Building


EDUCATION:

Ph.D. Aerospace Engineering, University of Minnesota, 1992.
M.S. Mechanics, Xian Jiaotong University, China, 1986.
B.S. Mechanical Engineering, Zhejiang University, China, 1982.


RESEARCH:

One area of my research is the study of hydrodynamic stability of core-annular flows; specifically the water lubricated transport of viscous crude oils through pipes. This line of research started with my Ph.D. thesis at Minnesota. The effects of hydrophobic pipe walls, the oil-water viscosity ratio, and the rotation of the pipe were examined. The developed theory agrees remarkably with the field test data in predicting the various flow regimes, interfacial wave characteristics, and the lower limit of oil viscosity for successful lubrication.

I have also worked on a number of other projects. They include: (a) the "change of type" in flows of viscoelastic fluids, and numerical solutions for flows of viscoelastic Maxwell fluids past a flat plate and a circular cylinder; (b) the simple mixture theory of miscible incompressible liquids; (c) the transient interfacial tension between miscible liquids; (d) the stability of miscible displacement in a Hele-Shaw cell; (e) the transient motion of a bubble in a spinning drop device, and analytic theory for the dynamic measurement of interfacial tension between a pair of very viscous liquids; (f) rheological measurements for viscoelastic fluids M1 and A1, for Lakeview and Venezuelan crude oils; (g) improved theory of rod-climbing (Weissenberg effect) for viscoelastic liquids whose viscosity and relaxation time changes with shear rate; (h) drag and moment in viscous potential flow; (i) energy stability analysis for plane Poiseuille flow; (j) capillary instability of a liquid thread in a circular pipe; (k) study of feedback controls to delay transition in planar Poiseuille flow.

The focus of my research is on understanding and modeling complex flows involving multiphase and polymeric fluids, specifically, the motion of solid particles, liquid drops and gas bubbles in those complex flows. Over the years, I have been developing highly efficient numerical methods for computing motions of large numbers of solid particles in flows of solid-fluid mixtures. I have developed a finite element package (PARTICLE MOVER) for simulating two- and three-dimensional motion of solid particles in Newtonian and viscoelastic fluids. My research not only has revealed some fundamental physical phenomena regarding particle-particle interactions, particle migration in various flows and flow induced particle microstructures, but also found wide industrial applications from studying motion of food particles in processing equipment, biological cells in blood flow, and the migration of propants in gel-like fluids used in hydraulic fracturing of oil reservoirs.

 

JOURNAL PUBLICATIONS:

  1. Ping Huang, Rong Jun Niu and Howard H. Hu, A new numerical method to solve modified Reynolds equation for magnetic head/disk working in ultra-thin gas films, Science in China Series E: Technological Sciences, Volume 51, Number 4, 424-434 (2008).
  2. A. Perrin and H.H. Hu, An Explicit Finite Difference Scheme with Stokes Flow Boundary Conditions for Particulate Flows, J. Computational Physics 227, 8776-8791 (2008).
  3. K. Mukundakrishnan, H.H. Hu, and P. S. Ayyaswamy, The dynamics of two spherical particles in a confined rotating flow: Pedaling motion, J. Fluid Mech 599, 169-204 (2008).
  4. P. Yue, J.J. Feng, C.A. Bertelo, and H.H. Hu, An Arbitrary Lagrangian-Eulerian method for simulating bubble growth in polymer foaming, J. Computational Physics 226, 2229-2249, (2007).
  5. S. Simic-Stefani, M. Kawaji, H.H. Hu, G-jitter-induced motion of a protein crystal under microgravity, J. of Crystal Growth 294, 373-384, (2006)
  6. P. Yue, C. Zhou, J.J. Feng, C.O. Gooch and H. H. Hu, Phase-Field Simulations of Interfacial Dynamics in Viscoelastic Fluids Using Finite Elements with Adaptive Meshing, Journal of Computational Physics 219, 47-67 (2006)
  7. T.N. Swaminathan, Howard H. Hu and A. Patel, Numerical analysis of the hemodynamics and embolus capture of a Greenfield filter vena cava filter. Journal of Biomechanical Engineering 128, 360-370 (2006).
  8. T. N. Swaminathan, K. Mukundakrishnan and H. H. Hu, Sedimentation of an ellipsoid inside an infinitely long tube at low and intermediate Reynolds numbers, J. Fluid Mech. 551 , 357-385 (2006)
  9. A. Perrin and H.H. Hu, An explicit finite-difference scheme for simulation of moving particles, J. Computational Physics 212,166-187, (2006).
  10. B.H. Yang, J. Wang, D.D. Joseph, H.H. Hu, T-W. Pan and R. Glowinski, Migration of a sphere in tube flow, J. Fluid Mech., 540, 109-131, (2005).
  11. K. Mukundakrishnan, P.S. Ayyaswamy, M. Risbud, H.H. Hu And I.M. Shapiro, modeling of phosphate ion transfer to the surface of osteoblasts under normal gravity and simulated microgravity conditions, Ann. N.Y. Acad. Sci. 1027, 85–98 (2004).
  12. S. Simic-Stefani, H.H. Hu and M. Kawaji, Numerical and Experimental Investigation of Solid Particle Motion in a Fluid Cell Under Microgravity, Microgravity Sci. Technol. XVI, 301-305, (2004).
  13. H. Liu, H.H. Bau and H.H. Hu, Electrophoresis of concentrically and eccentrically positioned cylindrical particles in a long tube, Langmuir, 20, 2628-2639, (2004).
  14. H. Liu, H.H. Bau and H.H. Hu, On the translation of a cylinder in a long tube, Physics of Fluids, 16, 998-1007, (2004).
  15. T.N. Swaminathan, H.H. Hu, Particle interactions in electrophoresis due to inertia, Journal of Colloid and Interface Science, 273, 324-330, (2004).
  16. H.H. Hu, Direct numerical simulations (DNS) of fluid-solid systems, Multiphase Science and Technology, 15, 193-240, (2003).
  17. D.D.. Joseph, J.J. Wang, R. Bai, B.H. Yang, H.H. Hu, Particle motion in a liquid film rimming the inside of a partially filled rotating cylinder, J. Fluid Mech. 496.139-164 (2003)
  18. Gan, H., Feng, J. J. & Hu, H. H. Simulation of the sedimentation of melting solid particles. Int. J. Multiphase Flow 29 (5), 751-769 (2003).
  19. Gan, H., Chang, J., Feng, J. J. & Hu, H. H. Direct numerical simulation of the sedimentation of solid particles with thermal convection. J. Fluid Mech. 481, 385-411 (2003).
  20. M. Yi, H.H. Bau & H.H. Hu, Peristaltically Induced Motion in a Closed Cavity with two Vibrating Walls, Physics of Fluids, 14, 184-197. (2002).
  21. N. Patankar and H.H. Hu, Finite Reynolds Number Effect on the Rheology of a Suspension of Neutrally Buoyant Solid Bodies in a Newtonian Fluid, International Journal of Multiphase Flow 28, 409-425 (2002).
  22. H.H. Hu, N. Patankar & M. Zhu, Direct Numerical Simulations of Fluid-Solid Systems Using Arbitrary-Lagrangian-Eulerian Technique, Journal of Computational Physics, 169, 427-462, (2001).
  23. N. Patankar and H.H. Hu, Rheology of a Suspension of Particles in a Viscoelastic Fluid, Journal of Non-Newtonian Fluid Mechanics, 96, 427-443, (2001).
  24. J. Feng and H.H. Hu, Meeting report: Workshop on multicomponent and multiphase fluid dynamics, International Journal of Multiphase Flow 26, 523-528 (2000).
  25. N. Patankar and H.H. Hu, A numerical investigation of the detachment of the trailing particle from a chain sedimenting in Newtonian and Viscoelastic Fluids, Journal of Fluid Engineering, 122, 527-521 (2000).
  26. H.H. Hu and D.D. Joseph, Lift on a Sphere Near a Plane Wall in a Second-Order Fluid, Journal of Non–Newtonian Fluid Mechanic, 88, 173-184 (1999).
  27. N. Patankar and H.H. Hu, Numerical simulation of electroosmotic flow, Analytical Chemistry 70, 1870-1881, (1998).
  28. P.Y. Huang, H. H. Hu and D. D. Joseph, Direct Simulation of the Motion of Elliptic Particles in Oldroyd-B Fluids, Journal of Fluid Mechanics 362, 297-325 (1998).
  29. P.Y. Huang, J. Feng, H. H. Hu and D. D. Joseph, Direct Simulation of the Motion of Solid Particles in Couette and Poiseuille Flows of Viscoelastic Fluids, Journal of Fluid Mechanics 343, 73-94 (1997).
  30. Q. Pan, K.I. Winey, H. H. Hu and R.J. Composto, Unstable Polymer Bilayers. III. The Effect of Film Thickness, Langmuir 13, 1758-1766 (1997).
  31. D.D. Joseph, A. Huang and H.H. Hu, Non-solenoidal Velocity Effects and Korteweg Stresses in Simple Mixtures of Incompressible Liquids, Physica D 97 104-125 (1996).
  32. H.H. Hu, Direct Simulation of Flows of Solid-Liquid Mixtures, International Journal of Multiphase Flow 22, 335-352 (1996).
  33. H.H. Hu, Motion of a Circular Cylinder in a Viscous Liquid between Parallel Plates, Theoretical and Computational Fluid Dynamics 7, 441-455, (1995).
  34. D.D. Joseph, R. Bai, T.Y. Liao, A. Huang and H.H. Hu, Parallel Pipelining, Journal of Fluid Engineering 117, 446–449 (1995).
  35. H.H. Hu and N. Patankar, Non-axisymmetric Instability of Core-Annular Flow, Journal of Fluid Mechanics 290, 213–224 (1995).
  36. T.N. Swaminathan, H.H. Hu, Particle interactions in electrophoresis due to inertia, Journal of Colloid and Interface Science, 273, 324-330, (2004).
  37. J. Feng, H.H. Hu and D.D. Joseph, Direct Simulation of Initial Value Problems for the Motion of Solid Bodies in a Newtonian Fluid, Part 2. Couette and Poiseuille Flows, Journal of Fluid Mechanics 277, 271–301 (1994).
  38. J. Feng, H.H. Hu and D.D. Joseph, Direct Simulation of Initial Value Problems for the Motion of Solid Bodies in a Newtonian Fluid, Part 1. Sedimentation, Journal of Fluid Mechanics 261, 95–134 (1994).
  39. T.Y. Liao, H.H. Hu and D.D. Joseph, White–Metzner Models for Rod Climbing in A1, Journal  of Non–Newtonian Fluid Mechanics 51, 111–124 (1994).
  40. H.H. Hu and D.D. Joseph, Evolution of a Liquid Drop in a Spinning Drop Tensiometer, Journal of Colloid and Interface Science 162, 331–339 (1994).
  41. D.D. Joseph, T.Y. Liao and H.H. Hu, Drag and Moment in Viscous Potential Flow, European Journal of Mechanics B/Fluids  12, 97–106 (1993).
  42. H.H. Hu, A. Fortes and D.D. Joseph, Experiments and Direct Simulations of Fluid Particle Motions, International Video Journal of Engineering Research 2 , 17–24 (1993).
  43. H.H. Hu, D.D. Joseph and M.J. Crochet, Direct Simulation of Fluid Particle Motions, Theoretical and Computational Fluid Dynamics  3, 285–306 (1992).
  44. H.H. Hu and D.D. Joseph, Miscible Displacement in a Hele–Shaw Cell, Z. Angew. Math. Phys. (ZAMP) 43, 626–644 (1992).
  45. D.D. Joseph, M. Arney, G. Gillberg, H.H. Hu, D. Hultman, C. Verdier and H. Vinagre, A Spinning Drop Tensioextensometer, Journal of Rheology 36, 621–662 (1992).
  46. H.H. Hu, O. Riccius, K.P. Chen, M. Arney and D.D. Joseph, Climbing Constant, Second Order Correction of Trouton's Viscosity, Wave Speed and Delayed Die Swell for M1, Journal of Non–Newtonian Fluid Mechanics 35, 287–307 (1990).
  47. H.H. Hu and D.D. Joseph, Numerical Simulation of Viscoelastic Flow past a Cylinder, Journal of Non–Newtonian Fluid Mechanics 37, 347–377 (1990).
  48. H.H. Hu, T.S. Lundgren and D.D. Joseph, Stability of Core–Annular Flow with Very Small Viscosity Ratio, Physics of Fluids A 2, 1945–1954 (1990).
  49. H.H. Hu and D.D. Joseph, Lubricated Pipelining: Stability of Core–Annular Flow. Part 2, Journal of Fluid Mechanics  205, 359–396 (1989).
  50. H.H. Hu and D.D. Joseph, Stability of Core–Annular Flow in a Rotating Pipe, Physics of Fluids A 1, 1677–1685 (1989).



Please direct inquiries to waddingt@seas.upenn.edu