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Book Experimental Investigation of High Speed Boundary Layers with Wall Roughness

Download or read book Experimental Investigation of High Speed Boundary Layers with Wall Roughness written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive investigation of the influence of surface roughness on the mean and turbulent flow properties of a high-speed turbulent boundary layer flow was performed. Six wall topologies, including a smooth and five rough surfaces consisting of three random sand-grain plates and two uniformly machined plates (k = 0 - 1.7 mm), were tested at three high Reynolds number (Re/m = 2 x lO (exp 7) Mach numbers (0.22, 0.65 and 2.75) . Mean flow measurements included surveys of the velocity and density. Turbulence quantities included measurements of the kinematic velocity turbulence intensities, mass flux turbulence intensities, kinematic Reynolds shear stress, compressible Reynolds shear stress, density-transverse-velocity fluctuation correlation, velocity spectra, auto-correlations, micro- and integral-scales and turbulent structure angles. Numerical simulations included evaluating three algebraic turbulence models with a boundary layer program. A three-year program was performed.

Book An Experimental Investigation of the Turbulent Boundary Layer Over a Wavy Wall

Download or read book An Experimental Investigation of the Turbulent Boundary Layer Over a Wavy Wall written by Asher Sigal and published by . This book was released on 1971 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Experimental Investigation of Pressure Driven Three dimensional Turbulent Boundary Layers

Download or read book An Experimental Investigation of Pressure Driven Three dimensional Turbulent Boundary Layers written by Stanford University. Thermosciences Division and published by . This book was released on 1987 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental Investigation of the Influence of the Turbulent Boundary Layer on the Pressure Distribution Over a Rigid Two dimensional Wavy Wall

Download or read book Experimental Investigation of the Influence of the Turbulent Boundary Layer on the Pressure Distribution Over a Rigid Two dimensional Wavy Wall written by Lado Muhlstein and published by . This book was released on 1971 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Turbulent Boundary Layers on a Systematically Varied Rough Wall

Download or read book Turbulent Boundary Layers on a Systematically Varied Rough Wall written by and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of an experimental investigation of the flow over a model roughness are presented. The series of roughness consists of close-packed pyramids in which both the height and the slope were systematically varied. The aim of this work was to document the mean flow and subsequently gain insight into the physical roughness scales which contribute to drag. The mean velocity profiles for all nine rough surfaces collapse with smooth-wall results when presented in velocity-defect form, supporting the use of similarity methods. The results for the six steepest surfaces indicate that the roughness function U+ scales almost entirely on the roughness height with little dependence on the slope of the pyramids. However, DeltaU+ for the three surfaces with the smallest slope does not scale satisfactorily on the roughness height, indicating that these surfaces might not be thought of as surface "roughness" in a traditional sense but instead surface "waviness."

Book An Experimental Investigation of the Near wall Region of a Three dimensional Incompressible Turbulent Boundary Layer Relaxing in a Zero Pressure Gradient

Download or read book An Experimental Investigation of the Near wall Region of a Three dimensional Incompressible Turbulent Boundary Layer Relaxing in a Zero Pressure Gradient written by Kattingeri Sheshagiri Hebbar and published by . This book was released on 1976 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Experimental Investigation Towards the Active Control of Turbulent Boundary Layers

Download or read book An Experimental Investigation Towards the Active Control of Turbulent Boundary Layers written by Stuart Alan Jacobson and published by . This book was released on 1995 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Open Channel Turbulent Boundary Layers and Wall Jets on Rough Surfaces

Download or read book Open Channel Turbulent Boundary Layers and Wall Jets on Rough Surfaces written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For many industrial and environmental flows, the momentum and convective heat transfer rates at the surface are determined by the turbulence structure in the near-wall region. Although many flows of practical interest occur on rough surfaces, our understanding and ability to predict rough wall turbulent flows lags far behind the corresponding technology for smooth surfaces. This provides reasonable grounds for additional refined rough wall measurements with the expectation of improving our physical understanding of practically relevant turbulent flows. This thesis reports an experimental investigation of wall roughness effects on the characteristics of turbulent boundary layers and wall jets. The measurements are obtained for smooth wall and three different roughness elements using a laser-Doppler anemometer. An insightful presentation of the results requires that the correct scaling laws must be used. In the case of the turbulent boundary layer, the appropriateness of the log law proposed by Millikan (1938) to model the overlap region of the mean flow and the power laws proposed by Barenblatt (1993) and George and Castillo (1997) is compared. The boundary layer results show that the theory proposed by George and Castillo (1997) has important advantages over the log law in modeling the mean velocity profiles as well as predicting the wall shear stress. The results also show that wall roughness increases the turbulence fluctuations and transport terms, which suggests that rough wall turbulence models must explicitly account for roughness effects in order to predict the mixing characteristics accurately. This promises to provide significant challenges to rough wall turbulence models. The wall jet results show that wall roughness increases the inner layer thickness but the jet half-width does not show any important sensitivity to surface roughness. The spread rates for the jet half-width are higher than the values obtained in earlier measurements. This may be attribute.

Book Experimental Investigation of coherent structures in turbulent boundary layers

Download or read book Experimental Investigation of coherent structures in turbulent boundary layers written by Candace Elaine Wark and published by . This book was released on 1989 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: