Download or read book Experimental Study of Turbulence Generation and Control by Fractal Grids written by S. M. M. Salim and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence generation and control have been an immense interest among scientists and researchers due to the fact that nearly all industrial flows are turbulent. In some cases, turbulence is highly desired, for example chemical plants need higher turbulence for the efficient mixing of various substances whereas, in oil and pipe industries, whereas, turbulence in the pipe flows causes higher energy input to sustain the flow along the pipe length. Thus, control of turbulence directly contributes to cutting costs. The existing approaches to control such flows are case specific and no single universal approach exists owing to the lack of understanding of underlying physics. Many approaches have been taken to generate turbulence in laboratory set-ups for the past hundred years to study turbulence control. One such approach is the use of a rectangular grid through which the fluid is forced to generate so called grid turbulence. In contrast, we have made use of fractal geometry to generate turbulence for similar study. The self-similar edge characteristic of the fractal grids is thought to play the vital role in the enhanced mixing properties. Four sets of fractal grids, each with equal flow area, were used in the study. Our results from the experiments conducted in a circular wind tunnel indicate that it is possible to significantly improve the generation and control of turbulence by the introduced fractal approach.

Download or read book Experimental Study of Turbulence Generation and Control by Fractal Grids written by S. M. Muztaba Salim and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fractal Flow Design How to Design Bespoke Turbulence and Why written by Yasuhiko Sakai and published by Springer. This book was released on 2016-06-21 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on turbulent flows generated and/or influenced by multiscale/fractal structures. It consists of six chapters which demonstrate, each one in its own way, how such structures and objects can be used to design bespoke turbulence for particular applications and also how they can be used for fundamental studies of turbulent flows.

Download or read book An Experimental Investigation of the Effect of Fractal Grids on the Near and Full Field Structure of a Turbulent Round Jet written by Eric Plançon and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project involves the experimental analysis of a jet with different nozzle configurations. The first configuration being a classic round nozzle and the second is modified adding a "fractal grid" by modifying the flow behavior and turbulent parameters. Both cases will be analyzed by an optical method, PIV, which is able to solve the velocity vector of a flow measuring the displacement of the particles of the flow. These particles have been initially added to the flow through a seeder PIV method not only provides an analysis of the speed but turbulent fluctuations of the velocity, the Reynolds stress and vorticity in case 3D PIV is used. Measuring supersonic speeds or the fact that it is a non-intrusive optical technique explains the reason PIV it is one of the most common experimental technique for analyzing flows. Reynolds stress is the component of the total stress tensor obtained by averaging the Navier-Stokes equations that define our turbulent flow. Averaging these equations explains where the turbulent fluctuations come. The simulations carried out show a comparison between the two configurations for all the turbulent parameters depending on the different regions of interest. The aim of this thesis is to understand the mechanisms and parameters involved in a turbulent flow but also contribute to the research of the jet noise produced by under the all sized structures present in the flow. Moreover, the use of "fractal grid" is being common among large companies for mixing the steady and accelerated flow more efficiently, noise reduction and even reduce the fuel consumption due to its more efficient combustion.

Download or read book Experimental Study of Turbulent Flow Generated by a Pulsating Grid written by Sean D. M. O'Connell and published by . This book was released on 1994 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Multiple Scales on Fractal grid generated Turbulence written by Alexis Kathleen Omilion and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractal grids, having patterns that repeat at different length scales, mimic the multi-scale characteristic of objects of complex appearance in nature, such as branching pulmonary network, river network, trees, and cumulus clouds. Understanding the role that multiple length scales have in momentum and energy transport is essential for effective utilization of fractal grids in a wide variety of engineering applications. While previous studies have solidified the dominant effect of the largest scale of fractal grids, effects of the additional scales on the generated turbulent flow remain unclear. This research is to determine how the smaller fractal scales (and the interaction between the multiple scales) influence the turbulence statistics of the induced flow and the pressure drop across a fractal square grid using well-controlled water-tunnel experiments. Instantaneous and ensemble-averaged velocity fields are obtained by a planar Particle Image Velocimetry (PIV) for a set of fractal square grids (N = 1, 2, 3 and 4) at the Reynolds number of 3400. The static pressure drop across the grids are measured by a differential pressure transducer. Flow fields indicate that the multiple jets, wakes and the shear layers produced by the multiple scales are the fundamental flow physics that promote momentum transport in the turbulence. In addition, the multiple scales cause a redistribution of the turbulent kinetic energy and a change in the vortex shedding mechanism behind the grids. The grid of 3 fractal scales (N = 3) produces higher turbulence intensity levels than the grid with 4 fractal scales (N = 4) despite having a lower blockage ratio and pressure drop, owing to the suppression of vortex shedding by the additional scale of the grid of N = 4. To better predict the location of peak turbulence intensity, the wake interaction length scale model is modified to incorporate the effects of the interactions among multiple scales by the effective mesh size and an empirical scaling coefficient Beta. Considering the capability of fractal grids to enhance momentum and energy transport, this work can potentially benefit a wide variety of applications where energy-efficient mixing or convective heat transfer is a key process.

Download or read book An Experimental Study of Grid Turbulence in a Liquid written by Carol Joan Russo and published by . This book was released on 1975 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AN EXPERIMENTAL STUDY OF GRID TURBULENCE IN A THERMALLY STRATIFIED FLOW written by RICHARD DOUGLAS MONTGOMERY and published by . This book was released on 1974 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Studies on the Turbulent Flow Behind Grids written by I. C. T. Nisbet and published by . This book was released on 1957* with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the International Conference on Aerospace System Science and Engineering 2021 written by Zhongliang Jing and published by Springer Nature. This book was released on 2022-07-08 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book collects selected papers presented at the 5th International Conference on Aerospace System Science and Engineering (ICASSE 2021), organized by Shanghai Jiao Tong University, China, hosted by Moscow Aviation Institute, Russia. It provides a forum for experts in aeronautics and astronautics to share new ideas and findings. ICASSE conference has been organized annually since 2017 and host in Shanghai, Moscow, and Toronto in turn, where the three regional editors of journal Aerospace Systems are located. This book presents high-quality contributions in the subject area of Aerospace System Science and Engineering, including topics such as: Trans-space vehicle systems design and integration, Air vehicle systems, Space vehicle systems, Near-space vehicle systems, Opto-electronic system, Aerospace robotics and unmanned system, Aerospace robotics and unmanned system, Communication, navigation and surveillance, Dynamics and control, Intelligent sensing and Information fusion, Aerodynamics and aircraft design, Aerospace propulsion, Avionics system, Air traffic management, Earth observation, Deep space exploration, Bionic micro-aircraft/spacecraft.

Download or read book An experimental study of grid generated freestream turbulence and its influence on velocity and temperature boundary layers on circular cylinders written by Lasse Hanarp and published by . This book was released on 1981 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Grid Turbulence in Compressible Flow written by Philip J. Zwart and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The flow downstream of a grid in a wind tunnel is of considerable interest for two reasons. Theoretically, it represents a good approximation to the idealized concept of homogeneous and isotropic turbulence, and therefore provides a benchmark to evaluate various analytical theories of turbulence. On the practical side, grids and screens are used extensively in the management of turbulence in a variety of applications. Experimental studies of grid turbulence are numerous in incompressible flow but far scarcer in compressible flow. The present study considers the characteristics of grid turbulence over a range of Mach numbers, M, ranging from the essentially incompressible (M = 0.16), through the moderate subsonic ($0.16 M 0.7)$ and high subsonic $(0.7 M 1.0),$ to the supersonic (M = 1.55). The experiments comprise flow visualization, performed with the shadowgraph method, and mean and fluctuating velocity measurements, made with a laser-Doppler velocimeter. Characteristics of the flow near the grid were visualized in a demonstration nozzle using the schlieren technique. In the moderate subsonic regime, flow visualization indicated that the flow near the grid underwent major changes as M increased. The turbulence intensity and decay characteristics were also found to be influenced, which was attributed to the changes in the flow near the grid. In the high subsonic regime, an unsteady quasi-normal shock was present in the test section. This induced relatively large velocity fluctuations and anisotropic turbulence. In the supersonic regime, stationary oblique shocks generated by the grid were present throughout the test section, which interfered with the turbulence and introduced errors in the measurement technique.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fractal Classical and Active Grid Turbulence written by Robert Jason Hearst and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study of Turbulence in a Density Stratified Shear Flow written by C. A. G. Webster and published by . This book was released on 1962 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of Unsteady Turbulent Flows written by Phone-Nan Wang and published by . This book was released on 1976 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct and Large Eddy Simulation VII written by Vincenzo Armenio and published by Springer Science & Business Media. This book was released on 2010-04-28 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: After Surrey in 1994, Grenoble in 1996, Cambridge in 1999, Enschede in 2001, Munich in 2003 and Poiters in 2005, the 7th Workshop, DLES7, will be held in Trieste, again under the auspices of ERCOFTAC. Following the spirit of the series, the goal of this latest workshop is to establish a state-of-the-art of DNS and LES techniques for the computation and modeling of transitional/turbulent flows covering a broad scope of topics such as aerodynamics, acoustics, combustion, multiphase flows, environment, geophysics and bio-medical applications. This gathering of specialists in the field should once again be a unique opportunity for discussions about the more recent advances in the prediction, understanding and control of turbulent flows in academic or industrial situations.