Structure Of Turbulence And Drag Reduction

Structure of Turbulence and Drag Reduction

In 1976 a similar titled IUTAM Symposium (Structure of Turbulence and Drag Reduction) was held in Washington . However, the progress made during the last thirteen years as weil as the much promising current research desired a second one this year. In Washington drag reduction by additives and by direct manipulation of the walls (compliant walls and heated surfaces) were discussed. In the meantime it became evident that drag reduction also occurs when turbulence is influenced by geometrical means, e.g. by influencing the pressure distribution by the shape of the body (airfoils) or by the introduction of streamwise perturbances on a body (riblets). In the recent years turbulence research has seen increasing attention being focused on the investigation of coherent structures, mainly in Newtonian fluids. We all know that these structures are a significant feature of turbulent flows, playing an important role in the energy balance in such flows. However their place in turbulence theories as weil as the factors influencing their development are still poorly understood. Consequently, the investigation of phenomena in which the properties of coherent structures are alte red provides a promising means of improving our understanding of turbulent flows in general.

Turbulence Structure and Modulation

Controlling turbulence is an important issue for a number of technological applications. Several methods to modulate turbulence are currently being investigated. All of them are based on the introduction of some sort of perturbation into the flow field which affect turbulence coherent structures responsible for turbulence transfer mechanisms. The scope of the book is to describe several aspects of turbulence structure and modulation and to explain and discuss the most promising techniques in detail.

Structure of Turbulence and Drag Reduction