Wei Liao

Tel: +1m(757) 864-5042; FAX: +1 (757) 325-6701

Email: wliao@nianet.or ; wei.liao@nasa.gov

Education

  • Ph.D. in CFD, Dept of Mech. Engineering, National University of Singapore, Singapore, 2004
  • M.S. in Aerodynamics, Nanjing University of Aeronautics and Astronautics, China, 1998
  • B.S. in Jet Propulsion, Nanjing University of Aeronautics and Astronautics, China, 1995

Research Interest

  • Flow instability, laminar flow control, turbulence simulation and modeling;
  • Computational aerodynamics and optimization design of complex configurations;
  • Kinetic methods for non-equilibrium thermo-chemical flows; and
  • Bio-inspired flows and unsteady flows over flapping wings/foils.

Current Research

3D CFD, Boundary Layer Stability Analysis and Optimization Design Based On Unstructured Flow Solvers: NASA’s Environmentally Responsible Aviation (ERA) Project has selected Discrete Roughness Elements (DRE) as one of the laminar flow control technologies for further evaluation and development for potential application to transport aircraft. The objectives of the current research are: 1) to make a computational assessment of the G-3 wing-glove designed to attain natural laminar flow using the unstructured-grid Navier-Stokes code, FUN3D and the Langley stability and transition code, LASTRAC; 2) to evaluate the effectiveness of the DRE technology at high Reynolds numbers of relevance to transport aircraft; 3) to enable FUN3D to produce “stability-quality” mean flow, so that its adjoint capability could be exploited for laminar flow wing design by coupling with LASTRAC.

Kinetic Methods and Non-Equilibrium Flows: Kinetic methods have many virtues over conventional methods, especially for non-equilibrium flows featured by rarefaction, multi-temperature, multi-species or chemical reaction. Liao’s research interests regarding gas kinetic scheme (GKS) include: 1) Multi-scale and multi-physics phenomena in non-thermochemical-equilibrium (NTE) high-speed and micro flows; 2) NTE turbulence under high Mach number conditions; 3) Combining GKS with novel numerical techniques, such as high-order methods, multigrid, implicit methods, and so on, to overcome intrinsic stiffness caused by multi-scale nature of non-equilibrium systems.

Propulsion and Power Extraction Performance of Flapping Wings:  Flapping wings are crucial to the design of efficient micro air vehicle (MAV) and energy extraction equipment, which may take advantage of renewable energy originated from tides, hydro or wind. Although much progress has been made, there remain a number of challenges for a complete understanding of flapping-foil and -wing hydrodynamics, including unsteady flow physics, three-dimensional features, fluid-structure interactions, flow transition from laminar to turbulence, and so on.

Selected Publications

  • W. Liao, M. Malik, E. Lee-Rausch, F. Li, E. J. Nielsen, C.-L. Chang and M. Choudhari. Boundary-layer stability analysis of the mean flows obtained using unstructured grids, in 42nd AIAA Fluid Dynamics Conference and Exhibit, New Orleans, Louisiana, 25 – 28 June 2012.
  • M. Malik, W. Liao, E. Lee-Rausch, F. Li, M. Choudhari and C.-L. Chang. Computational analysis of the G-III laminar flow glove, AIAA-2011-3525.
  • Q. Xiao, W. Liao, S. Yang and Y. Peng. How motion trajectory a_ects energy extraction performance of a biomimic energy generator with an oscillating foil? Renewable Energy 37(1): 61-75 (2012).
  • L.-S. Luo., W. Liao, X. Chen, Y. Peng and W. Zhang. Numerics of the lattice Boltzmann method: Effects of collision models on the lattice Boltzmann simulations. Physics Review E 83(5): 056710 (2011).
  • Q. Xiao and W. Liao. Numerical investigation of angle of attack profile on propulsion performance of an oscillating foil. Computers and Fluids 39: 1366-1380 (2010).
  • W. Liao, Y. Peng and L.-S. Luo. Effect of multi-temperature non-equilibrium on compressible homogeneous turbulence. Physics Review E 81: 046704 (2010).
  • W. Liao, E. P. C. Koh, H. M. Tsai and F. Liu. Euler calculations with embedded Cartesian grids and small perturbation boundary conditions. Journal of Computational Physics 229: 3523-3542 (2010).
  • W. Liao and H.M. Tsai. Aerodynamic design optimization on overset grids using the adjoint method. International Journal for Numerical Methods in Fluids, 63: 1332-1356 (2010).
  • Y. Peng, W. Liao, L.-S. Luo and L.-P. Wang. Comparison of the lattice Boltzmann and pseudo-spectral methods for decaying turbulence. Part I. Low-order statistics. Computers and Fluids 39: 568-591 (2010).
  • W. Liao, Y. Peng and L.-S. Luo. Gas kinetic schemes for DNS of compressible homogeneous turbulence. Physics Review E 80: 046702 (2009).
  • Q. Xiao and W. Liao. Numerical study of asymmetric effect on a pitching foil. International Journal of Modern Physics C 20:1663-1680 (2009).
  • W. Liao, B. Diskin, and L.-S. Luo. Textbook-efficiency multigrid solver for three-dimensional unsteady compressible Navier-Stokes equations. Journal of Computational Physics 227: 7160-7177 (2008).
  • W. Liao, Y. Peng, L.-S. Luo, and K. Xu. Numerical simulation of shock wave structure using gas kinetic scheme. Progress in Computational Fluid Dynamics 8: 97-108 (2008).
  • W. Liao, L.-S. Luo, and K. Xu. Gas kinetic scheme for continuum and near-continuum hypersonic flows. AIAA Journal of Spacecraft and Rockets 44:1232-1240 (2007)
  • W. Liao, J. Cai, and H. Tsai. A multigrid overset grid flow solver with implicit hole cutting method. Computer Methods in Applied Mechanics and Engineering 196:1701-1715 (2007