NATIONAL INSTITUTE OF AEROSPACE

Yi Liu

Tel: (757) 864-6124; Fax: (757) 864-3970

Email: yiliu@nianet.org

Education

  • Ph.D. in Aerospace Engineering, Georgia Institute of Technology, Atlanta, Georgia, May 2003
  • M.S. in Aero-acoustics, Beijing University of Aeronautics & Astronautics, Beijing, China, Apr. 1998
  • B.S. in Astronomy, Beijing University of Aeronautics & Astronautics, Beijing, China, Sept. 1994

Research Interests

Applying the Computational Fluid Dynamics (CFD) technique into the aerodynamic, acoustic and aeromechanic analysis and simulations in the following areas:

  • Rotorcraft aerodynamic analysis and acoustic prediction;
  • Micro-air vehicle and flapping wing aerodynamics;
  • Fixed wing aerodynamic analysis and application of circulation control and active flow control techniques;
  • Jet engine aerodynamic analysis and high-fidelity blade design method; and
  • High performance computing and parallel computing.

Current Research

Rotorcraft Computational Fluid Dynamics and Numerical Acoustic Analysis:  This research is focusing on the development of improved aerodynamic modeling and acoustic prediction capabilities through implementation of computational fluid dynamics (CFD) techniques. Focus will be directed toward key issues associated with implementing of coupling methods between CFD techniques, with the current generation of rotorcraft comprehensive analyses, and computational structural dynamics (CSD) analyses that incorporate a multi-body dynamics methodology. Other research being conducted includes: investigation of higher-order numerical algorithm and wake modeling methods on the effects of CFD rotor blade performance predictions. Besides the predictions of rotor blade performance and detailed flow/wake characteristics around rotor, the noise signature predictions at far field observers are also being improved with permeable surface coupling methods utilizing acoustic analysis to include the quadrupole source noise effects. Investigation of the prediction capability of the CFD methodologies on rotor loads, stability, blade pressure distribution, and acoustic signature will also be conducted.

Micro-Air Vehicle System Computational Fluid Dynamics Analysis: This research focuses on the development of CFD algorithms that improve the modeling of the micro-scale flapping wing aeromechanics phenomena. The purpose of this research is to develop and improve the analytical techniques that advance the state-of-the-art for predicting the unsteady vortex-dominated low-Reynolds-number flow associated with the micro-scale flapping-wing platforms. A numerical analysis code based on high-fidelity, unsteady, and low-Reynolds-number Navier-Stokes equations will be developed or improved upon from the existing code to simulate the complicated aeromechanic phenomena associated with the micro-scale flapping wing configurations. Coupling between CFD and CSD will also be implemented to count for the high degree flexibilities and large deformations of general membrane structured micro flapping wing configurations.

Recent Publications

  • Liu,Y., “Multidisciplinary Computational Rotor Noise Prediction for Helicopter Rotor in High-speed Forward Flight,” AIAA Paper 2011-846, 49th AIAA Aerospace meeting and exhibit, Orlando, FL, Jan. 4-7, 2011.
  • Liu, Y., Anusonti-Inthra, P., and Diskin, B., “Development and Validation of a Multidisciplinary Tool for Accurate and Efficient Rotorcraft Noise Prediction (MUTE),” NASA Technical Report, NASA/CR-2011-217057, 2011.
  • Liu, Y., Sankar, L. N., Robert, J. E., Ahuja, K. K., and R. Gaeta  “Computational Evaluation of the Steady and Pulsed Jet Effects on a Circulation Control Airfoil,” vol.8, chapter 22, AIAA Book Series, Applications of  Circulation Control Technologies, 2006
  • Liu, Y. “Rotor Airloads Prediction Refinement Using Aerodynamics /Structure Coupling,” 11th International Workshop on Rotorcraft Dynamics and Aero-elasticity, Oct. 12-14, 2005, Deerfield Beach, Florida.
  • Liu, Y., Sankar, L. N., “Computational Evaluation of Controlling Flap Edge Vortex and Tip Vortex Effects with Circulation Control Technique,”  45th AIAA Aerospace Meeting and Exhibit, Reno, NV, Jan. 8-11, 2007, AIAA Paper 2007-0473.
  • Liu, Y., Sankar, L. N., Robert, J. E., Ahuja, K. K., and R. Gaeta  “Computational Evaluation of the Steady and Pulsed Jet Effects on the Performance of a Circulation Control Wing Section,” AIAA Paper 2004-0056.
  • Liu, Y., Sankar, L. N., Robert, J. E., and Ahuja, K. K., “Numerical Simulation of the Steady and Unsteady Aerodynamics Characteristics of a Circulation Control Wing Airfoil,” AIAA Paper 2001-0704, Jan 8-11,2001.

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