EBookClubs

Read Books & Download eBooks Full Online

EBookClubs

Read Books & Download eBooks Full Online

Book An Experimental Study of Turbulent Boundary Layer Structure

Download or read book An Experimental Study of Turbulent Boundary Layer Structure written by Erich J. Plate and published by . This book was released on 1964 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report covers work done in preparation for a systematic investigation of the nature of aerodynamic roughness, and of the effect of thermal stratification on the turbulence structure in forced convection environments over rough and smooth surfaces. The investigations are based on data taken in a meteorological wind tunnel. After completion of the tunnel check out, exploratory measurements were made of the distributions of velocity and temperature in a thermally stratified flow (of unstable stratification) and of the velocity profiles above small sample plates covered with different types of sand roughness. A study of the flow of air over flexible roughness was the first comprehensive study which lead to definite conclusions. While the wind tunnel was readied for experimental work, side studies were undertaken for developing techniques for measuring profiles of mean velocities and mean temperatures, and for measuring fluctuations of temperatures and of velocities.

Book An Experimental Study of Turbulent Boundary Layer on Rough Walls

Download or read book An Experimental Study of Turbulent Boundary Layer on Rough Walls written by C. K. Liu and published by . This book was released on 1966 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental data are presented on flow structure, mean, and fluctuating velocities in turbulent boundary layers over a family of flat surfaces with transverse roughness elements made of square bars of variable spacing. All flows were incompressible and had zero streamwise pressure gradient. The flow structures are described for surfaces extending from hydraulically smooth to fully rough. A distinct flow pattern is observed in the wall region for each of four cases: smooth, skimming, wake-interference and isolated-roughness flow. Maximum roughness was observed with a ratio of gap to bar width of approximately 11. The most obvious effect of an increase in surface roughness is the distinct increase of turbulence production and the concomittant increase in the value of eddy viscosity. It is shown that this increase in eddy viscosity increases the total thickness of the layer in the same way that an increase in molecular viscosity would do in a laminar layer. The normalization of eddy viscosity for the outer portion of the layer as suggested by Clauser is found to apply to the rough surfaces studied. (Author).

Book AN EXPERIMENTAL STUDY OF THE STRUCTURE OF TURBULENCE NEAR THE WALL THROUGH CORRELATION MEASUREMENTS IN A THICK TURBULENT BOUNDARY LAYER

Download or read book AN EXPERIMENTAL STUDY OF THE STRUCTURE OF TURBULENCE NEAR THE WALL THROUGH CORRELATION MEASUREMENTS IN A THICK TURBULENT BOUNDARY LAYER written by Bo-Jang Tu and published by . This book was released on 1966 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation is described in which emphasis is given to revealing the structure of turbulence near the wall in a boundary layer. Measurements made include space-time correlations between the fluctuating wall pressure and the span-wise velocity component w, and between the various velocity components. The velocity correlations include measurements of the space-time correlation of the streamwise component of the fluctuating wall shear stress. Experiments have been conducted in a thick (5 in.) turbulent boundary layer with zero pressure gradient which is produced by natural transition on a smooth surface. Sufficient data have been obtained to allow the proposal of a qualitative model for the structure of turbulence near the wall. The proposed model outlines the sequence of events that results in the production of intense pressure and velocity fluctuations by stretching of the vorticity after it is produced by viscous stresses within and near the edge of the viscous sublayer. The measurements are in qualitative agreement with the model. Qualitative agreement means that the size and shape of the contours of constant correlation and the sign of the measured correlations are in agreement with the proposed model for the turbulent structure. (Author).

Book An Experimental Study of Turbulence Production Near a Smooth Wall in a Turbulent Boundary Layer with Zero Pressure gradient

Download or read book An Experimental Study of Turbulence Production Near a Smooth Wall in a Turbulent Boundary Layer with Zero Pressure gradient written by Heung-tae Kim and published by . This book was released on 1968 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of the turbulent boundary layer on a smooth wall with zero pressure gradient has been studied experimentally. Emphasis has been given to the production of turbulence in the inner layers. Intensive studies of a few.

Book Experimental Study of a Three dimensional Shear driven Turbulent Boundary Layer with Streamwise Adverse Pressure Gradient

Download or read book Experimental Study of a Three dimensional Shear driven Turbulent Boundary Layer with Streamwise Adverse Pressure Gradient written by David Michael Driver and published by . This book was released on 1989 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Experimental Study of Turbulent Boundary Layers Subjected to High Free stream Turbulence Effects

Download or read book An Experimental Study of Turbulent Boundary Layers Subjected to High Free stream Turbulence Effects written by Edgar Orsi Filho and published by . This book was released on 2005 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis was on nominally two-dimensional turbulent boundary layers at zero pressure gradient subjected to high free-stream turbulent intensities of up to 7.9% in preparations for high free-stream turbulence studies on three-dimensional boundary layers, which will be done in the future in the Aerospace and Ocean Engineering Boundary Layer Wind Tunnel at Virginia Tech. The two-dimensional turbulent flow that will impinge three-dimensional bodies needed to be characterized, before the three-dimensional studies can be made. An active turbulence generator designed to create high free-stream turbulence intensities in the wind tunnel was tested and modified in order to obtain the lowest possible mean flow non-uniformities. A seven-hole pressure probe was used to obtain planes of mean velocity measurements. A three-component state of the art laser-Doppler velocimeter (LDV) was used to obtain mean and fluctuating velocities. Previous high free-stream turbulence studies have been reviewed and are discussed, and some of the previously published data of other authors have been corrected. Based on the measurements obtained with the LDV, it was also determined that the semi-log law of the wall is valid for high free-stream turbulence cases, but with different constants than the ones proposed by Coles, where the constants for the high free-stream cases may be dependent on the turbulence intensity. For the first time, the skin friction coefficient (Cf) was deduced from the viscous sublayer. The difference between the U_tau obtained in the viscous sublayer mean velocity profile and the U_tau obtained in the semi-log layer was 1.5%. The skin friction coefficient was determined to increase by 10.5% when the two-dimensional turbulent boundary layer was subjected to high free-stream turbulence effects. Spectral data obtained with the LDV, were compared to the von Kármán model spectrum and to the Pope's model spectrum, where the von Kármán spectrum was proven to fit the spectral data slightly better than the Pope's spectrum. Finally, the Hancock-Bradshaw-Blair parameter obtained for this experiment agreed very well with previously published data.

Book A Study of Turbulent Boundary Layer Structure

Download or read book A Study of Turbulent Boundary Layer Structure written by John Leask Lumley and published by . This book was released on 1986 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An experimental study of the structure of a flat plate turbulent boundary layer using laser doppler velocimetry

Download or read book An experimental study of the structure of a flat plate turbulent boundary layer using laser doppler velocimetry written by T. Gunnar Johansson and published by . This book was released on 1988 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental Investigation of Turbulent Boundary Layer with Uniform Blowing at Moderate and High Reynolds Numbers

Download or read book Experimental Investigation of Turbulent Boundary Layer with Uniform Blowing at Moderate and High Reynolds Numbers written by Gazi Hasanuzzaman and published by Cuvillier Verlag. This book was released on 2022-01-18 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental investigation in turbulent boundary layer flows represents one of the canonical geometries of wall bounded shear flows. Utmost relevance of such experiments, however, is applied in the engineering applications in aerospace and marine industries. In particular, continuous effort is being imparted to explore the underlying physics of the flow in order to develop models for numerical tools and to achieve flow control. Flow control experiments have been widely investigated since 1930’s. Several flow control technique has been explored and have shown potential benefit. But the choice of control technique depends largely on the boundary condition and the type of application. Hence, friction drag of subsonic transport aircraft is intended to be reduced within the scope of this Ph. D. topic. Therefore, application of active control method such as microblowing effect in the incompressible, zero pressure gradient turbulent boundary layer was investigated. A series of experiments have been performed in two different wind tunnel facilities. Wind tunnel from Department of Aerodynamics and Fluid Mechanics (LAS) was used for the measurements for moderate Reynolds number range in co-operation with the wind tunnel from Laboratoire de M´ecanique de Feiret Lille for large Reynolds number range. Measurements are conducted with the help of state-of-the-art techniques such as Laser Doppler Anemometry, Particle Image Velocimetry and electronic pressure sensors.

Book An Experimental Study of Two dimensional Turbulent Boundary Layer Separation

Download or read book An Experimental Study of Two dimensional Turbulent Boundary Layer Separation written by Thomas Gregory Tillman and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: