摘要
Most fluid flows in nature and engineering applications are in the state of turbulence.Turbulent motions usually exhibit a wide range of spatial and temporal scales,such as the flow of natural gas and oil in pipelines,the wakes of cars and submarines,the boundary layer of an aircraft,the current in the ocean surface,the atmospheric boundary layer,the interstellar gas clouds(gaseous stars),and the Earth’s wake in the solar wind.Turbulence can greatly improve the heat and mass transfer efficiency of macroscopic flow.For example,chemical engineers use turbulence to mix up and homogenize fluid components and to increase chemical reaction rates in liquids or gases.However,turbulence can also lead to increases in drag,aerodynamic heat,and hydrodynamic and aerodynamic noise.For instance,the aerodynamic loading of high-speed aircraft can be significantly increased due to turbulence.
基金
Project supported by the National Natural Science Foundation of China(No.91752000)
