Distributed Roughness Receptivity In A Flat Plate Boundary Layer
Download Distributed Roughness Receptivity In A Flat Plate Boundary Layer full books in PDF, epub, and Kindle. Read online free Distributed Roughness Receptivity In A Flat Plate Boundary Layer ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Author | : Matthew Scott Kuester |
Publisher | : |
Total Pages | : |
Release | : 2015 |
Genre | : |
ISBN | : |
Download Distributed Roughness Receptivity in a Flat Plate Boundary Layer Book in PDF, Epub and Kindle
Surface roughness can affect boundary layer transition by acting as a receptivity mechanism for transient growth. Several experiments have investigated transient growth created by discrete roughness elements; however, very few experiments have studied transient growth initiated by distributed surface roughness. Some of the work in this field predicts a "shielding" effect, where smaller distributed roughness displaces the boundary layer away from the wall and shields larger roughness peaks from the incoming boundary layer. This dissertation describes an experiment specifically designed to study the shielding effect. Three roughness configurations, a deterministic distributed roughness patch, a slanted rectangle, and the combination of the two, were manufactured using rapid prototyping and installed flush with the wall in a flat plate boundary layer. The main objective was to compare the wakes of the discrete roughness and the combined roughness to examine if the distributed roughness shields the discrete roughness. Naphthalene flow visualization and hotwire anemometry were used to characterize the boundary layer in the wakes of the different roughness configurations. For roughness Reynolds numbers (Re[subscript k]) between 113 and 230, the distributed roughness initiated small amplitude disturbances that underwent transient growth. The discrete roughness element created a pair of high- and low-speed streaks in the boundary layer at a sub-critical Reynolds number (Re[subscript k]) = 151). At a higher Reynolds number (Re[subscript k]) = 220), the discrete element created a turbulent wedge 15 boundary layer thicknesses downstream. When the distributed roughness was added around the discrete roughness, the wake amplitude decreased at the sub-critical Reynolds number, and transition was delayed by two boundary layer thicknesses at the higher Reynolds number. The distributed roughness redirects energy from longer spanwise wavelength modes to shorter spanwise wavelength modes. The presence of the distributed roughness also decreased the growth rate of secondary instabilities in the roughness wake. This dissertation documents the first detailed measurements of transient growth over streamwise-extended distributed roughness and demonstrates that the shielding effect has the potential to delay roughness-induced transition. The results from this experiment lay the ground work for future studies of roughness receptivity and transient growth. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152606
Author | : Tahani R. Amer |
Publisher | : |
Total Pages | : 188 |
Release | : 1995 |
Genre | : Boundary layer |
ISBN | : |
Download Non-linear Boundary-layer Receptivity Due to Distributed Surface Roughness Book in PDF, Epub and Kindle
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : 28 |
Release | : 1992 |
Genre | : |
ISBN | : |
Download Boundary-layer Receptivity Due to Distributed Surface Imperfections of a Deterministic Or Random Nature Book in PDF, Epub and Kindle
Author | : M. N. Kogan |
Publisher | : |
Total Pages | : 50 |
Release | : 1997 |
Genre | : |
ISBN | : |
Download Receptivity of Flat-Plate Boundary Layer in a Non-Uniform Free Stream (Vorticity Normal to the Plate) Book in PDF, Epub and Kindle
Author | : Dawn Elizabeth Nichols |
Publisher | : |
Total Pages | : |
Release | : 2001 |
Genre | : |
ISBN | : |
Download Boundary Layer Receptivity of a Flat Plate with a Rounded Leading Edge Book in PDF, Epub and Kindle
Author | : Nay Lin |
Publisher | : |
Total Pages | : 342 |
Release | : 1992 |
Genre | : Boundary layer |
ISBN | : |
Download Receptivity of the Boundary Layer Over a Flat Plate with Different Leading-edge Geometries Book in PDF, Epub and Kindle
Author | : Nay Lin |
Publisher | : |
Total Pages | : 286 |
Release | : 1989 |
Genre | : Boundary layer |
ISBN | : |
Download Receptivity of the Boundary Layer on a Semi-infinite Flat Plate with an Elliptic Leading Edge Book in PDF, Epub and Kindle
Author | : A.V. Boiko |
Publisher | : Springer Science & Business Media |
Total Pages | : 273 |
Release | : 2013-03-09 |
Genre | : Technology & Engineering |
ISBN | : 3662047659 |
Download The Origin of Turbulence in Near-Wall Flows Book in PDF, Epub and Kindle
The Origin of Species Charles Darwin The origin of turbulence in fluids is a long-standing problem and has been the focus of research for decades due to its great importance in a variety of engineering applications. Furthermore, the study of the origin of turbulence is part of the fundamental physical problem of turbulence description and the philosophical problem of determinism and chaos. At the end of the nineteenth century, Reynolds and Rayleigh conjectured that the reason of the transition of laminar flow to the 'sinuous' state is in stability which results in amplification of wavy disturbances and breakdown of the laminar regime. Heisenberg (1924) was the founder of linear hydrody namic stability theory. The first calculations of boundary layer stability were fulfilled in pioneer works of Tollmien (1929) and Schlichting (1932, 1933). Later Taylor (1936) hypothesized that the transition to turbulence is initi ated by free-stream oscillations inducing local separations near wall. Up to the 1940s, skepticism of the stability theory predominated, in particular due to the experimental results of Dryden (1934, 1936). Only the experiments of Schubauer and Skramstad (1948) revealed the determining role of insta bility waves in the transition. Now it is well established that the transition to turbulence in shear flows at small and moderate levels of environmental disturbances occurs through development of instability waves in the initial laminar flow. In Chapter 1 we start with the fundamentals of stability theory, employing results of the early studies and recent advances.
Author | : Yifei Yu |
Publisher | : Springer Nature |
Total Pages | : 201 |
Release | : |
Genre | : |
ISBN | : 3031536703 |
Download Mechanism of Hairpin Vortex Formation by Liutex Book in PDF, Epub and Kindle
Author | : Andreas Dillmann |
Publisher | : Springer |
Total Pages | : 855 |
Release | : 2016-03-28 |
Genre | : Technology & Engineering |
ISBN | : 3319272799 |
Download New Results in Numerical and Experimental Fluid Mechanics X Book in PDF, Epub and Kindle
This book presents contributions to the 19th biannual symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. Special emphasis is given to collaborative research projects conducted by German scientists and engineers from universities, research-establishments and industries. By addressing a number of cutting-edge applications, together with the relevant physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field. Though the book’s primary emphasis is on the aerospace context, it also addresses further important applications, e.g. in ground transportation and energy.