Numerical simulation on the flow fields near the dimpled and the smooth revolution bodies are performed and compared by using SST k-ω turbulence model, to explain the reasons of friction and base drag reductions on t...Numerical simulation on the flow fields near the dimpled and the smooth revolution bodies are performed and compared by using SST k-ω turbulence model, to explain the reasons of friction and base drag reductions on the bionic dimpled surface and the control behaviors of dimpled surface to boundary layer near wall of the revolution body. The simulation results show that the dimpled surface reduces the skin friction drag through reducing the velocity gradient and turbulent intensity, and reduces the base drag through weakening the pumping action on the flow behind the revolution body caused by the external flow; the low speed rotating vortexes in the dimples segregate the external flow and the revolution body; and the low speed rotating vortexes forming in the bottom of dimples can produce negative skin friction.展开更多
Through the numerical simulation investigation,the turbulent drag reduction mechanisms of shark riblet surface are explored. In allusion to the characteristics of riblets surface,the computation region,grids and flow ...Through the numerical simulation investigation,the turbulent drag reduction mechanisms of shark riblet surface are explored. In allusion to the characteristics of riblets surface,the computation region,grids and flow parameters are dealt with reasonably. These present simulation results show preliminarily that 1) only the near-wall flow field above riblet surfaces is affected by riblets,and the flow within riblets is slow and quiescent; 2) the viscous sub-layer above riblet surface is thicker; 3) the shear stress and the local friction coefficient above the riblet surface are reduced,and the drag reduction quantity is larger at the bottom of riblets than that at the top. Numerical simulation investigation on the riblet surface in the paper can provide a reference for future research in this field.展开更多
基金Sponsored by the National Natural Science Foundation of China (50635030)the Technology Development Plan of Jilin Province ( 20096032)+1 种基金the Major Program of Science and Technology Development of Jilin Province (09ZDGG001)the Youth Research Start-up Fund of Agriculture Department of Jilin University ( 4305050102K7)
文摘Numerical simulation on the flow fields near the dimpled and the smooth revolution bodies are performed and compared by using SST k-ω turbulence model, to explain the reasons of friction and base drag reductions on the bionic dimpled surface and the control behaviors of dimpled surface to boundary layer near wall of the revolution body. The simulation results show that the dimpled surface reduces the skin friction drag through reducing the velocity gradient and turbulent intensity, and reduces the base drag through weakening the pumping action on the flow behind the revolution body caused by the external flow; the low speed rotating vortexes in the dimples segregate the external flow and the revolution body; and the low speed rotating vortexes forming in the bottom of dimples can produce negative skin friction.
基金Sponsored by National Nature Science Foundation of China (10672136,50835009)Science and Technology Innovation Foundation of NWPU(2008KJ02012)
文摘Through the numerical simulation investigation,the turbulent drag reduction mechanisms of shark riblet surface are explored. In allusion to the characteristics of riblets surface,the computation region,grids and flow parameters are dealt with reasonably. These present simulation results show preliminarily that 1) only the near-wall flow field above riblet surfaces is affected by riblets,and the flow within riblets is slow and quiescent; 2) the viscous sub-layer above riblet surface is thicker; 3) the shear stress and the local friction coefficient above the riblet surface are reduced,and the drag reduction quantity is larger at the bottom of riblets than that at the top. Numerical simulation investigation on the riblet surface in the paper can provide a reference for future research in this field.
