With rapid development of economics since the 1980s, people have been increasingly realized that the environment plays an important role in the sustainable development of society and economy. Now, the study of environment gradually become to refinement and quantification, and the accumulation of large amounts of data has the requirement of modeling and mathematization, which Impel the research of environmental science from macroscopic to microscopic and the combination of macroscopic research and microscopic research. The mechanic style of combining analysis, computation and experiment, which forms in its developing process, is extremely advantageous to the deepening understanding of basic rule in environmental questions. For example, the boundary-layer theory in fluid mechanics has greatly promoted the research of atmospheric dynamics and made weather forecasts become possible; the research of forced convection discovered that the western strengthening of wind-driven circulation is arose by rotation; the theoretical study of multi-phase flow has greatly enhanced the quantitative prediction accuracy of river sediment transport and pollutant dispersion. So, the profound intercrossing and fusion between mechanics and environmental science has become an important trend in current scientific research of environment. The environmental mechanics, a new subject forming in the combination of mechanics and environmental science, is not only the significant requirement of economical and social sustainable development but also a new important growth point of mechanical subject.
Environmental mechanics involves many fields, mainly including atmospheric environment, water environment, geological environment, earth-interface process, environmental disaster, environmental multi-phase flow, theoretical modeling, calculation methods and experimental technology, and so on.
Over the past 20 years, the international researches in environmental mechanics have achieved a rapid development and the researches in our country were basically in step with the international researches. Chinese mechanical researchers actively participate in the environmental study, and have gotten gratifying achievements. For instant, they studied the pollutants in air or water through experiments in the environment wind tunnel and the layered tank and provided the important basis for nuclear power plant design, urban planning CBD and the control of Suzhou river; they played a role in the estuarine and coastal projects through combining channel regulation of the Yangtze River estuary and the control of Pearl River estuary with researches in estuarine unsteady flow and sediment transport; they provided the scientific basis for environmental control of western China through establishing the two-dimensional dynamics model of soil and sand sediment on slope, extending the model to small drainage area, analyzing affecting factors of erosion, and giving critical slope of soil erosion; they tried hard to reveal the sand charged quantity in wind-sand flow, the basic laws of the electric field in windblown sand drift and its influences to wind sand flow and telecommunication; they realized the theoretical predictions of the evolution and main features of wind-sand flow and eolian physiognomy and provided design basis for sand-fixing engineering; they studied earth's interface process, simulated the atmospheric boundary layer with vegetation and analyzed the effects of crust layer on soil-water move and its ecological effects; they obtained the effects of wave age and stability on air-sea exchange coefficient by means of turbulence simulation and offered the basis for parameterization of climate model; they also studied the typhoon abnormal track by vortex dynamics, and numerically simulated disasters of typhoon and storm tide. After more than 20 years of accumulation, China has gradually formed the basic framework of environmental mechanics, developed a research team of environmental mechanics, which have made contributions to China's sustainable development.
In the 21st century, the research of environmental mechanics in China should pay more attention to the organic combination of mechanism research, regularity analysis and the prevention measures. On one hand we should emphasize its general scientific questions, including the basic theories and methods of flowing and transportation; interaction among gas, fluid and solid; the coupling of multi-phase, multi-component and multi-process; and scaling effects of modeling experiments in environmental mechanics, and so on. On the other hand, we should aim at economical development of west and coastal regions, urbanization process, and actual problems in significant project: including the control of arid environments in western China (soil erosion, sand storm, desertification control and so on); transportation of river flow, bed-loads in estuary and coast and pollutants as well as their influence regularities on ecological environment; the urban air pollution; and the happening mechanism and prediction of significant environmental disasters (tropical cyclones, flood, landslide/mud-rock flow, global-warming), and so on.
Environmental mechanics is a new cross-subject and is in the stage of constantly developing and deepening understanding now. Actively promoting the development of environmental mechanics is the demand of Chinese economic and social sustainable development, and is also the important responsibility of scientific researchers, who should continuously promote the development of environmental mechanics by in-depth discussions, exchanges, personnel training and fruitful works, and make new contributions to Chinese economic and social sustainable development.
In order to reflect recent progress in the related research from one side, Science in China Series G decides to publish a special subject on environmental mechanics so that more researchers will know the latest achievements in environmental mechanics. This subject is responded by lots of researchers and they had enthusiastically submitted their works to this subject. The contents in this subject include researches of mechanical problems in environments and disasters related to water, soil, atmospheres and biology. Through careful peer review of correlative experts, (¼¸?) papers have been decided to be published in this periodical and other accepted manuscripts will be published in the near future. The environmental mechanical research will be one of important contents concerned by Science in China Series G. We hope that will promote the innovative research of Chinese scholars in environmental mechanics and the subject's development in this area, and we will unceasingly support and publish the latest results of our country's researchers in this field.