Author: Paul John WaltrupPublisher:
ISBN:
Category :
Languages : en
Pages : 232
Book Description
An Experimental Investigation of a Compressible Turbulent Boundary Layer Subjected to a Systematic Variation of Adverse Pressure Gradients
An Experimental Investigation of the Compressible Turbulent Boundary Layer with a Favorable Pressure Gradient
Author: David L. BrottPublisher:
ISBN:
Category : Compressibility
Languages : en
Pages : 104
Book Description
The paper describes the results of a detailed experimental investigation of a two-dimensional turbulent boundary layer in a favorable pressure gradient where the free-stream Mach number varied from 3.8 to 4.6 and the ratio of wall to adiabatic-wall temperature has a nominal value of 0.82. Detailed profile measurements were made with pressure and temperature probes; skin friction was measured directly with a shear balance. The velocity- and temperature-profile results were compared with zero pressure gradient and incompressible results. The skin-friction data were correlated with momentum-thickness Reynolds number and pressure-gradient parameter. (Author).
Method for Predicting Compressible Turbulent Boundary Layers in Adverse Pressure Gradients
Author: Shimer Zane PinckneyPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 68
Book Description
Experimental Investigation of Compressible Boundary Layers Under the Influence of Pressure Gradients
Author: Raymond C. WierPublisher:
ISBN: 9781423574361
Category : Compressibility
Languages : en
Pages : 149
Book Description
This study examined the effect of mild pressure gradients on the mean and turbulent flow of high-speed boundary layers. Three Mach numbers (1.7, 3.0 and 5.0) were investigated. Three pressure gradients were examined; a zero pressure gradient (ZPG), a favorable pressure gradient (FPG), and a combined pressure gradient (CPG). The CPG consisted of an adverse pressure gradient followed by a favorable pressure gradient. Conventional pressure probes, hot- wire and particle image velocimetry (PIV) were used to examine the flow. Measurement included mean velocity, velocity turbulence intensity, mass flux turbulence intensity and energy spectra. Instantaneous (10 nsec) Mie scattering flow visualizations were acquired. Qualitatively, the flow visualizations indicated that the turbulent flow structures were strongly affected by the pressure gradients. For the Mach 2,8 case, the PIV contours and the hot-wire profiles both indicated that the boundary layer thickness increased by 40% and decreased by 100% relative to the ZPG for the favorable and adverse pressure gradients, respectively. Further, the PIV and hot-wire data indicated that the axial turbulence intensity levels increased by 22% for the CPG and decreased by 25% for the FPG. The energy spectra data indicated that once a pressure gradient was applied (favorable or adverse) the low frequency energy increased followed by a rapid decay. Lastly, it was found that nominally 20 to 30 PIV images were sufficient for mean flow boundary layer velocities, but 93 images (the maximum recorded in this study) were insufficient to adequately resolve Reynolds shear stresses.
Experimental Investigation of the Effect of a Systematically Varied Adverse Pressure Gradient on the Growth of Turbulent Boundary Layers
Author: Joseph Alfred SchetzAn Experimental Investigation of Compressible Turbulent Boundary Layers in an Adverse Pressure Gradient with and Without Surface Curvature
Author: Jung-Hua ChouPublisher:
ISBN:
Category : Compressibility
Languages : en
Pages : 258
Book Description
Compressible Turbulent Boundary Layers
Author: An Experimental Investigation of the Compressible Turbulent Boundary Layer with a Favorable Pressure Gradient
Author: David L. BrottPublisher:
ISBN:
Category : Compressibility
Languages : en
Pages : 80
Book Description
The paper describes the results of a detailed experimental investigation of a two-dimensional turbulent boundary layer in a favorable pressure gradient where the free-stream Mach number varied from 3.8 to 4.6 and the ratio of wall to adiabatic-wall temperature has a nominal value of 0.82. Detailed profile measurements were made with pressure and temperature probes; skin friction was measured directly with a shear balance. The velocity- and temperature-profile results were compared with zero pressure gradient and incompressible results. The skin-friction data were correlated with momentum-thickness Reynolds number and pressure-gradient parameter. (Author).
An Experimental Investigation of Vortex Generation in a Turbulent Boundary Layer Undergoing Adverse Pressure Gradient
Author: Victor ZakkayPublisher:
ISBN:
Category : Turbulent boundary layer
Languages : en
Pages : 52
Book Description
Experimental Investigation of Turbulent Boundary Layers with Pressure Gradient and Heat Transfer at Mach Number 4
Author: J. S. HahnPublisher:
ISBN:
Category :
Languages : en
Pages : 57
Book Description
An experimental investigation of the behavior of a turbulent boundary layer subjected to adverse and favorable pressure gradients was conducted at Mach number 4 for a free-stream Reynolds number of 0.500,000 per inch. Two severe pressure gradients were imposed on the boundary layer by interchangeable contoured centerbodies inside a large hollow cylinder for cold-wall and adiabatic-wall temperature conditions. Imposition of either of the adverse pressure gradients significantly decreased the natural growth rate of the boundary-layer displacement thickness, whereas the favorable pressure gradient had opposite effects; momentum thickness was relatively unaffected by pressure gradient. A pressure gradient increase of about 30 percent caused relatively small changes in the skin friction, heat-transfer rate, and the characteristic boundary-layer parameters. Wall cooling effects (T sub w/t sub 0 approximately 0.3) on the boundary-layer thickness parameters were nearly insignificant, in comparison with the adiabatic-wall results. Heat-transfer distributions were similar to the local skin friction results based on free-stream conditions. (Author).