Turbulence And Coherent Structures

An expert review of recent progress in the study of turbulent flows with a focus on recently identified organized structures.
This book reviews the recent progress in the study of the turbulent flows that sculpt the Earth’s surface, focusing in particular on the organized structures that have been identified in recent years within turbulent flows. These coherent flow structures can include eddies or vortices at the scale of individual grains, through structures that scale with the flow depth in rivers or estuaries, to the large-scale structure of flows at the morphological or landform scale. These flow structures are of wide interest to the scientific community because they play an important role in fluid dynamics and influence the transport, erosion and deposition of sediment and pollutants in a wide variety of fluid flow environments.

Space exploration and advanced astronomy have dramatically expanded our knowledge of outer space and made it possible to study the indepth mechanisms underlying various natural phenomena caused by complex interaction of physical-chemical and dynamical processes in the universe. Huge breakthroughs in astrophysics and the planetary s- ences have led to increasingly complicated models of such media as giant molecular clouds giving birth to stars, protoplanetary accretion disks associated with the solar system’s formation, planetary atmospheres and circumplanetary space. The creation of these models was promoted by the development of basic approaches in modern - chanics and physics paralleled by the great advancement in the computer sciences. As a result, numerous multidimensional non-stationary problems involving the analysis of evolutionary processes can be investigated using wide-range numerical experiments. Turbulence belongs to the most widespread and, at the same time, the most complicated natural phenomena, related to the origin and development of organized structures (- dies of different scale) at a definite flow regime of fluids in essentially non-linear - drodynamic systems. This is also one of the most complex and intriguing sections of the mechanics of fluids. The direct numerical modeling of turbulent flows encounters large mathematical difficulties, while the development of a general turbulence theory is hardly possible because of the complexity of interacting coherent structures. Three-dimensional non-steady motions arise in such a system under loss of la- nar flow stability defined by the critical value of the Reynolds number.