Public Reporting burden for this collection of information is estimated to average 1 hour per res... more Public Reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comment regarding this burden estimates or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188,) Washington, DC 20503.
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011
This paper presents a hybrid fluid solver which couples a grid-free viscous vortex particle metho... more This paper presents a hybrid fluid solver which couples a grid-free viscous vortex particle method with gridbased unstructured Computational Fluid Dynamics (CFD) solvers. The solver was developed to address the challenging rotor wake and aerodynamic interaction problem. The viscous ...
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2010
The material point method (MPM) combined with adaptive mesh refinement (AMR) technique is applied... more The material point method (MPM) combined with adaptive mesh refinement (AMR) technique is applied to investigate complicated fluid-structure interactions (FSI) such as aircraft wing flutter and other aeroelastic problems. The advantage of MPM over traditional fluid-structure interaction (FSI) methods is its computational efficiency, accuracy and robustness. MPM avoids explicit discretization of convection terms in momentum equations and the fluid-structure interaction is realized by coupling the fluid and solid stress at the interface. The states of material points are updated through the solution on background Cartesian grid node which is fixed during the calculation, thus no mesh distortion problem needs to be dealing with in the case of large deformation. The dynamic AMR can effectively decrease the total number of background mesh nodes and material points for complicated
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2010
The advanced Computational Fluid Dynamics (CFD) techniques that address the current limitations o... more The advanced Computational Fluid Dynamics (CFD) techniques that address the current limitations of Cartesian-based Navier-Stokes CFD schemes are explored in current investigation. Three promising methods of implementing improved wall boundary conditions are applied: (1) the enhanced diamond path stencil approach, (2) the reformulated extended extrapolation boundary condition, and (3) the ghost cell method. Several initial testing cases have been conducted with all these three boundary conditions, including the flow past a circular cylinder, flow past a flat plate at different inclined angles and flow past an AGARD RAE2822 airfoil. All the results show the effectiveness of these boundary conditions in resolving both laminar and turbulent boundary layer. Among all these methods, the extended extrapolation boundary condition attains the better results than the other two methods.
Public Reporting burden for this collection of information is estimated to average 1 hour per res... more Public Reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comment regarding this burden estimates or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188,) Washington, DC 20503.
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011
This paper presents a hybrid fluid solver which couples a grid-free viscous vortex particle metho... more This paper presents a hybrid fluid solver which couples a grid-free viscous vortex particle method with gridbased unstructured Computational Fluid Dynamics (CFD) solvers. The solver was developed to address the challenging rotor wake and aerodynamic interaction problem. The viscous ...
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2010
The material point method (MPM) combined with adaptive mesh refinement (AMR) technique is applied... more The material point method (MPM) combined with adaptive mesh refinement (AMR) technique is applied to investigate complicated fluid-structure interactions (FSI) such as aircraft wing flutter and other aeroelastic problems. The advantage of MPM over traditional fluid-structure interaction (FSI) methods is its computational efficiency, accuracy and robustness. MPM avoids explicit discretization of convection terms in momentum equations and the fluid-structure interaction is realized by coupling the fluid and solid stress at the interface. The states of material points are updated through the solution on background Cartesian grid node which is fixed during the calculation, thus no mesh distortion problem needs to be dealing with in the case of large deformation. The dynamic AMR can effectively decrease the total number of background mesh nodes and material points for complicated
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2010
The advanced Computational Fluid Dynamics (CFD) techniques that address the current limitations o... more The advanced Computational Fluid Dynamics (CFD) techniques that address the current limitations of Cartesian-based Navier-Stokes CFD schemes are explored in current investigation. Three promising methods of implementing improved wall boundary conditions are applied: (1) the enhanced diamond path stencil approach, (2) the reformulated extended extrapolation boundary condition, and (3) the ghost cell method. Several initial testing cases have been conducted with all these three boundary conditions, including the flow past a circular cylinder, flow past a flat plate at different inclined angles and flow past an AGARD RAE2822 airfoil. All the results show the effectiveness of these boundary conditions in resolving both laminar and turbulent boundary layer. Among all these methods, the extended extrapolation boundary condition attains the better results than the other two methods.
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Papers by Hongwu Zhao