Characteristics of Whole-vehicle Drag Reduction in High-speed Vehicle Through Opposing Jet Flow
To study the drag reduction characteristics of head opposing jet flow for the whole high-speed vehicle,a calculation model is established for sphere bicone,and flow field is solved by using multi-component axial symmetry Navier-Stokes equations.The influence laws of the opposing jet on the wave drag,friction drag,and base drag are studied by using the height of free stream,and the total pressure ratio of the jet and free stream.The calculation results show that the increase of the total pressure ratio reduces the wave drag and base drag by changing the flow field structure,and it leads to a temperature decrease and velocity gradient increase within the boundary layer.The dominant boundary velocity gradient can lead to an increase in friction drag.For high-altitude conditions,the friction drag has a high proportion of total drag and a better drag reduction effect,so it is better to choose an appropriate total pressure ratio.For low-altitude conditions,the base drag has a high proportion of total drag and a better drag reduction effect,so it is better to choose a high total pressure ratio.Considering the cost-effectiveness ratio of drag reduction and opposing jet mass flow,high-altitude flight conditions with a small total pressure ratio can be chosen.
numerical simulationopposing jetdrag reductionheight of free streamtotal pressure ratio of the jet and free stream
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