Numerical Studies of Laminar and Turbulent Drag Reduction

Numerical Studies of Laminar and Turbulent Drag Reduction
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Total Pages: 34
Release: 2018-08-13
Genre:
ISBN: 9781725106895

Two-dimensional incompressible flow over wavy surfaces is studied numerically by spectral methods. Turbulence effects are modeled. Results for symmetric and asymmetric wave forms are presented. Effect of propagating surface waves on drag reduction is studied. Comparisons between computer simulations and experimental results are made. Balasubramanian, R. and Orszag, S. A. Unspecified Center NASA-CR-3498, CHI-57 NAS1-16237...

Turbulent Drag Reduction by Surfactant Additives

Turbulent Drag Reduction by Surfactant Additives
Author: Feng-Chen Li
Publisher: John Wiley & Sons
Total Pages: 233
Release: 2012-01-10
Genre: Science
ISBN: 1118181115

Turbulent drag reduction by additives has long been a hot research topic. This phenomenon is inherently associated with multifold expertise. Solutions of drag-reducing additives are usually viscoelastic fluids having complicated rheological properties. Exploring the characteristics of drag-reduced turbulent flows calls for uniquely designed experimental and numerical simulation techniques and elaborate theoretical considerations. Pertinently understanding the turbulent drag reduction mechanism necessities mastering the fundamentals of turbulence and establishing a proper relationship between turbulence and the rheological properties induced by additives. Promoting the applications of the drag reduction phenomenon requires the knowledge from different fields such as chemical engineering, mechanical engineering, municipal engineering, and so on. This book gives a thorough elucidation of the turbulence characteristics and rheological behaviors, theories, special techniques and application issues for drag-reducing flows by surfactant additives based on the state-of-the-art of scientific research results through the latest experimental studies, numerical simulations and theoretical analyses. Covers turbulent drag reduction, heat transfer reduction, complex rheology and the real-world applications of drag reduction Introduces advanced testing techniques, such as PIV, LDA, and their applications in current experiments, illustrated with multiple diagrams and equations Real-world examples of the topic’s increasingly important industrial applications enable readers to implement cost- and energy-saving measures Explains the tools before presenting the research results, to give readers coverage of the subject from both theoretical and experimental viewpoints Consolidates interdisciplinary information on turbulent drag reduction by additives Turbulent Drag Reduction by Surfactant Additives is geared for researchers, graduate students, and engineers in the fields of Fluid Mechanics, Mechanical Engineering, Turbulence, Chemical Engineering, Municipal Engineering. Researchers and practitioners involved in the fields of Flow Control, Chemistry, Computational Fluid Dynamics, Experimental Fluid Dynamics, and Rheology will also find this book to be a much-needed reference on the topic.

Laminar Drag Reduction

Laminar Drag Reduction
Author: Keizo Watanabe
Publisher: Bentham Science Publishers
Total Pages: 107
Release: 2015-06-05
Genre: Technology & Engineering
ISBN: 1681080842

The phenomenon of resistance to motion through a fluid is believed to be a function of fluid-wall interaction. This theory is based on the assumption that under certain conditions a real fluid does not usually slip on the wall in contact with it and displays laminar flow. This set of conditions is known as a ‘no slip boundary condition’. But if a fluid is passed alongside a wall, the drag reduction in the laminar flow region can be calculated. In Laminar Drag Reduction, the frictional drag of an internal or an external fluid flow along a certain kind of hydrophobic wall is investigated. An analytic approach towards the mechanism of drag reduction is employed using Navier-Stokes existence and smoothness equations. The experimental results presented in this book show that frictional drag of a fluid alongside this hydrophobic wall decreases in comparison with fluid flow along a conventional wall or surface. This form of laminar drag reduction represents a relatively new area of research, where the laminar flow can be controlled by microscopic surface modifications, allowing fluid flows to slip over a wall. Laminar Drag Reduction brings information about some interesting phenomena related to fluid slippage on a highly water-repellent surface. Readers, physics graduates and senior researchers alike, can benefit from the information presented in this book to tackle more challenging questions in fluid mechanics research.

Aerodynamic Drag Reduction Technologies

Aerodynamic Drag Reduction Technologies
Author: Peter Thiede
Publisher: Springer Science & Business Media
Total Pages: 382
Release: 2013-06-29
Genre: Technology & Engineering
ISBN: 3540453598

------------------------------------------------------------ This volume contains the Proceedings of the CEAS/DragNet European Drag Reduction Conference held on 19-21 June 2000 in Potsdam, Germany. This conference, succeeding the European Fora on Laminar Flow Technology 1992 and 1996, was initiated by the European Drag Reduction Network (DragNet) and organised by DGLR under the auspice of CEAS. The conference addressed the recent advances in all areas of drag reduction research, development, validation and demonstration including laminar flow technology, adaptive wing concepts, turbulent and induced drag reduction, separation control and supersonic flow aspects. This volume which comprises more than 40 conference papers is of particular interest to engineers, scientists and students working in the aeronautics industry, research establishments or academia.