Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane...Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane of symmetry by quadratic interpolation of the LDV （Laser Doppler Velocimetry） measurements, for a wall jet-to-boundary layer velocity ratio of 2. The results, which have relevance to flows encountered in powered-lift aircraft operating in ground effect, quantify the structure of the complex ground vortex flow. The analysis of turbulent energy equation terms using the measured data revealed that production by normal and shear stresses are both very important to the turbulent structure of the impact zone of the ground vortex. This is an indication that the modeling of turbulence of a ground vortex requires a good representation of the production by normal stresses which is most important in the collision zone.展开更多
This paper presents a fundamental gaskinetic study on high speed rarefied jets expanding into vacuum from a cluster of planar exits.Based on the corresponding exact expressions for one planar jet,this paper straightfo...This paper presents a fundamental gaskinetic study on high speed rarefied jets expanding into vacuum from a cluster of planar exits.Based on the corresponding exact expressions for one planar jet,this paper straightforwardly derives the combined multiple jet flowfield solutions of density and velocity components,however,for the combined temperature and pressure solutions,extra attention shall be practiced.Several direct simulation Monte Carlo simulation results are provided and they validate these analytical solutions of rarefied planar jet flows.展开更多
文摘Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane of symmetry by quadratic interpolation of the LDV （Laser Doppler Velocimetry） measurements, for a wall jet-to-boundary layer velocity ratio of 2. The results, which have relevance to flows encountered in powered-lift aircraft operating in ground effect, quantify the structure of the complex ground vortex flow. The analysis of turbulent energy equation terms using the measured data revealed that production by normal and shear stresses are both very important to the turbulent structure of the impact zone of the ground vortex. This is an indication that the modeling of turbulence of a ground vortex requires a good representation of the production by normal stresses which is most important in the collision zone.
文摘This paper presents a fundamental gaskinetic study on high speed rarefied jets expanding into vacuum from a cluster of planar exits.Based on the corresponding exact expressions for one planar jet,this paper straightforwardly derives the combined multiple jet flowfield solutions of density and velocity components,however,for the combined temperature and pressure solutions,extra attention shall be practiced.Several direct simulation Monte Carlo simulation results are provided and they validate these analytical solutions of rarefied planar jet flows.
