A numerical method based on solutions of Euler/Navier-Stokes （N-S） equations is developed for calculating the flow field over a rotor in hover. Jameson central scheme, van Leer flux-vector splitting scheme, advectio...A numerical method based on solutions of Euler/Navier-Stokes （N-S） equations is developed for calculating the flow field over a rotor in hover. Jameson central scheme, van Leer flux-vector splitting scheme, advection upwind splitting method （AUSM） scheme, upwind AUSM/van Leer scheme, AUSM＋ scheme and AUSMDV scheme are implemented for spatial discretization, and van Albada limiter is also applied. For temporal discretization, both explicit Runge-Kutta method and implicit lower-upper symmetric Gauss-Seidel （LU-SGS） method are attempted. Simultaneously, overset grid technique is adopted. In detail, hole-map method is utilized to identify intergrid boundary points （IGBPs）. Furthermore, aimed at identification issue of donor elements, inverse-map method is implemented. Eventually, blade surface pressure distributions derived from numerical simulation are validated compared with experimental data, showing that all the schemes mentioned above have the capability to predict the rotor flow field accurately. At the same time, vorticity contours are illustrated for analysis, and other characteristics are also analyzed.展开更多
A numerical simulation method for parachute Fluid-Structure Interaction(FSI) problem using Semi-Implicit Method for Pressure-Linked Equations(SIMPLE) algorithm is proposed.This method could be used in both coupling co...A numerical simulation method for parachute Fluid-Structure Interaction(FSI) problem using Semi-Implicit Method for Pressure-Linked Equations(SIMPLE) algorithm is proposed.This method could be used in both coupling computation of parachute FSI and flow field analysis.Both flat circular parachute and conical parachute are modeled and simulated by this new method.Flow field characteristics at various angles of attack are further simulated for the conical parachute model.Comparison with the space-time FSI technique shows that this method also provides similar and reasonable results.展开更多
Numerical simulations of helicopter aerodynamic interactions among the main rotor,fuselage,engine inlets/outlets and slung loads of specific geometries have been conducted by very few researchers.In this work,the stea...Numerical simulations of helicopter aerodynamic interactions among the main rotor,fuselage,engine inlets/outlets and slung loads of specific geometries have been conducted by very few researchers.In this work,the steady-state compressible Reynolds-averaged navier-stokes equations are solved to study the aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution in three cases,namely MI-171V5,ROBIN and UH-60A.In the first case,the downwash flow provided by the rotor of the uniform actuator disc model induces a significant deflection of the airflow velocity.The vortex-shaped distribution and evolution are discussed in detail.The engine can effectively change the overall flow field.The asymmetry of the flow field is observed by using the non-uniform actuator disc model.Qualitative analysis of ROBIN and quantitative computation of UH-60A show a consistent accuracy of the rotating reference frame model for rotor.The blade tip vortex motion of UH-60A is simulated and its radial position prediction is compared to empirical formulas.While performing flow of UH-60A in hover,both the fuselage normal force and rotor lift decrease because of the impact of the body of revolution.展开更多
基金Innovation Foundation of BUAA for PhD Graduates (300522)
文摘A numerical method based on solutions of Euler/Navier-Stokes （N-S） equations is developed for calculating the flow field over a rotor in hover. Jameson central scheme, van Leer flux-vector splitting scheme, advection upwind splitting method （AUSM） scheme, upwind AUSM/van Leer scheme, AUSM＋ scheme and AUSMDV scheme are implemented for spatial discretization, and van Albada limiter is also applied. For temporal discretization, both explicit Runge-Kutta method and implicit lower-upper symmetric Gauss-Seidel （LU-SGS） method are attempted. Simultaneously, overset grid technique is adopted. In detail, hole-map method is utilized to identify intergrid boundary points （IGBPs）. Furthermore, aimed at identification issue of donor elements, inverse-map method is implemented. Eventually, blade surface pressure distributions derived from numerical simulation are validated compared with experimental data, showing that all the schemes mentioned above have the capability to predict the rotor flow field accurately. At the same time, vorticity contours are illustrated for analysis, and other characteristics are also analyzed.
基金supported by the National Natural Science Foundation of China (Grant No. 10577003)Monash University of Australia
文摘A numerical simulation method for parachute Fluid-Structure Interaction(FSI) problem using Semi-Implicit Method for Pressure-Linked Equations(SIMPLE) algorithm is proposed.This method could be used in both coupling computation of parachute FSI and flow field analysis.Both flat circular parachute and conical parachute are modeled and simulated by this new method.Flow field characteristics at various angles of attack are further simulated for the conical parachute model.Comparison with the space-time FSI technique shows that this method also provides similar and reasonable results.
文摘Numerical simulations of helicopter aerodynamic interactions among the main rotor,fuselage,engine inlets/outlets and slung loads of specific geometries have been conducted by very few researchers.In this work,the steady-state compressible Reynolds-averaged navier-stokes equations are solved to study the aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution in three cases,namely MI-171V5,ROBIN and UH-60A.In the first case,the downwash flow provided by the rotor of the uniform actuator disc model induces a significant deflection of the airflow velocity.The vortex-shaped distribution and evolution are discussed in detail.The engine can effectively change the overall flow field.The asymmetry of the flow field is observed by using the non-uniform actuator disc model.Qualitative analysis of ROBIN and quantitative computation of UH-60A show a consistent accuracy of the rotating reference frame model for rotor.The blade tip vortex motion of UH-60A is simulated and its radial position prediction is compared to empirical formulas.While performing flow of UH-60A in hover,both the fuselage normal force and rotor lift decrease because of the impact of the body of revolution.
