Modern turbulence and new challenges

The paper briefly reviews the progress in turbulence research in the 20th century and a number of issues are addressed based on achievements. The modern theroy of Navier-Stokes equation provides the theoretical basis for the development of turbulence research. The significance and bottle neck of DNS and the physical experiment in exploring turbulent flows are analyzed. The active manipulation of turbulence is directly guided by the knowledge of large-scale coherent structures. The existing problems in the large-eddy simulation are also pointed out. Scalar turbulence, which behaves quite different from fluid turbulence in many aspects, has drawn much attention in recent years. Besides the analysis of the difficulties in turbulence research, a number of examples are also presented to show how to use modern theory, computer and high technology to explore the nature of turbulence. The project supported by the National Natural Science Foundation of China (NSFC) (19572041 and 19732005)