PAST AND FUTURE EVOLUTIONS OF FLUID MECHANICS: THINKING TRIGGERED BY THE BATCHELOR CENTENNIAL EVENT

G.K. Batchelor is one of the giants of fluid mechanics in the in the twentieth century. He had made pioneering contributions in the field of homogeneous turbulence theory and low Reynolds number micro-fluid mechanics. He is the founder of Journal of Fluid Mechanics, one of the top journal in the field of fluid mechanics, and the department of applied mathematics and theoretical physics (DAMTP), whose spirit of pursuing physical and quantitative understanding of fluid flows has impressed the development of fluid mechanics in recent 100 years. He has cultivated and influenced a large number of scholars who have made outstanding achievements in numerous subjects of fluid mechanics, including turbulence theory, experimental fluid mechanics, turbulence stability, environmental fluid mechanics, multiphase fluid mechanics, magneto-hydrodynamics, micro- and nano-scale fluid mechanics, etc. Taking the G.K. Batchelor centennial event as an opportunity, this paper briefly reviews the evolution history of fluid mechanics in the past 300 years, including the three important stages of fluid mechanics: classical stage based on solid mathematics and physics foundation, the modern stage driven by application demands, and the contemporary stage characterized by discipline intersection and integration. Special concerns are concentrated on the formation, merging and inheritance of the distinct styles of the four schools in the modern stage of fluid mechanics in the past hundred years from the perspective of outstanding scholars and their key contributions to the discipline. The driving force and trend of the development of contemporary fluid mechanics are discussed taking wind-blown sand environmental mechanics as an example. It shows that fluid mechanics provides the basis for the development of branch disciplines, while the demands of branch disciplines drives the endogenous development of fluid mechanics which forms a spiral growth relationship. Finally, the progress spectrum and innovation trends of fluid mechanics in the future are revealed and discussed.