Author: Doyle D. KnightPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Three-dimensional Shock Wave Turbulent Boundary Layer Interactions Generated by a Sharp Fin at Mach 4
Author: Doyle D. KnightThree-dimensional Shock Wave-turbulent Boundary Layer Interactions at Mach 6
Author: C. Herbert LawPublisher:
ISBN:
Category : Aerodynamic heating
Languages : en
Pages : 52
Book Description
Experimental results of an investigation of the three-dimensional interaction between a skewed shock wave and a turbulent boundary layer are presented. Surface pressure and heat transfer distributions and oil flow photographs were obtained at a freestream Mach number of 5.85 and two Reynolds numbers of ten and twenty million per foot. The model configuration consisted of a shock generator mounted perpendicularly to a flat plate. The shock generator leading edge was sharp and nonswept and intersected the flat plate surface about 8.5 inches downstream of the flat plate leading edge. The shock generator surface was 7.55 inches long and 3 inches high and its angle to the freestream flow was adjusted from 4 to 20 degrees. The generated shock waves were of sufficient strength to produce turbulent boundary layer separation on the flat plate surface.
Theoretical Investigation of Three-Dimensional Shock Wave-Turbulent Boundary Layer Interactions. Part 2
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 71
Book Description
The focus of the research effort is the understanding of three-dimensional shock wave-turbulent boundary layer interactions. The approach uses the full mean compressible Navier-Stokes equations with turbulence incorporated through the algebraic turbulent eddy viscosity model of Baldwin and Lomax. During the present year of the research effort, the three-dimensional shock boundary layer interaction generated by a 10 deg sharp fin has been computed at Mach 3 for a Reynolds number 280000. These results, together with previous computations of the same configuration at Reynolds number = 930000, are compared with experimental data for pitot pressure and yaw angle. The agreement with the experimental data is good, and the theory accurately predicts the recovery of the boundary layer downstream of the interaction of Reynolds number = 280000. The computed flowfield is employed to analyze the structure of the 3-D interaction through contour plots of flow variables. Also, during the present year, the investigation of the 2-D turbulent supersonic compression corner at Mach 3 was completed. The relaxation modification to the Baldwin-Lomax model was found to yield reasonably accurate predictions of the upstream propagation of the surface for the Reynolds number range investigated. An additional computation at Mach 2 was performed, and the results were in general in agreement with the previous conclusions. (Author).
Three-Dimensional Shock Wave and Turbulent Boundary Layer Interactions
Author: Seymour M. BogdonoffPublisher:
ISBN:
Category :
Languages : en
Pages : 75
Book Description
An extensive experimental study of three-dimensional shock wave turbulent boundary layer interactions caused by shock generators defined solely by angles has been carried out at Mach 3. Sharp fins, sharp swept fins, swept wedges, and semi-cones have been used to generate a wide range of shock waves. The interaction of these waves with turbulent boundary layers has been investigated by surface flow visualization, mean surface static pressure distributions, flowfield surveys of total pressure and yaw, and several flowfield visualization techniques. Some exploratory high frequency surface pressure measurements have been carried out to evaluate the steadiness of these interactions. Scaling laws for both surface and flowfield features have been derived. Some limited studies were carried out at a Mach number of 2. A flowfield study has shown that the initial part of interactions caused by the same strength and geometrical shock wave generated by different shock generators are all similar. The 'footprints' of the interactions, as shown by surface flow visualization, can be categorized as approximately conical or cylindrical, and the boundaries between these two regions have been defined for both Mach 3 and Mach 2. There are still questions with regards to the detailed flowfield structures and physical mechanisms, but the three-dimensional interactions appeared to be less unsteady than that of two-dimensional separated flows.
Turbulent Shear-Layer/Shock-Wave Interactions
Author: J. DeleryPublisher: Springer Science & Business Media
ISBN: 3642827705
Category : Science
Languages : en
Pages : 434
Book Description
It was on a proposal of the late Professor Maurice Roy, member of the French Academy of Sciences, that in 1982, the General Assembly of the International Union of Theoretical and Applied Mechanics decided to sponsor a symposium on Turbulent Shear-Layer/Shock-Wave Interactions. This sympo sium might be arranged in Paris -or in its immediate vicinity-during the year 1985. Upon request of Professor Robert Legendre, member of the French Academy of Sciences, the organization of the symposium might be provided by the Office National d'Etudes et de Recherches Aerospatiales (ONERA). The request was very favorably received by Monsieur l'Ingenieur General Andre Auriol, then General Director of ONERA. The subject of interactions between shock-waves and turbulent dissipative layers is of considerable importance for many practical devices and has a wide range of engineering applications. Such phenomena occur almost inevitably in any transonic or supersonic flow and the subject has given rise to an important research effort since the advent of high speed fluid mechanics, more than forty years ago. However, with the coming of age of modern computers and the development of new sophisticated measurement techniques, considerable progress has been made in the field over the past fifteen years. The aim of the symposium was to provide an updated status of the research effort devoted to shear layer/shock-wave interactions and to present the most significant results obtained recently.
Experimental Study of Three-Dimensional Shock Wave Turbulent Boundary Layer Interaction - Scaling of Sharp and Blunt Fin-Induced Flowfields
Author: David S. DollingPublisher:
ISBN:
Category :
Languages : en
Pages : 61
Book Description
An experimental study of three-dimensional (3-D) shock wave turbulent boundary layer interaction has been carried out. Interactions generated by fin models having sharp and hemi-cylindrically blunted leading edges have been studied. Tests have been made using incoming turbulent boundary layer varying in thickness in the ratio of about 4:1. Extensive surface property measurements have been made on the test surface on which the incoming boundary layer developed and on the fin itself. All of these tests were carried out at a nominal freestream Mach number of 3, a freestream unit Reynolds number of about 63 million per meter, and under approximately adiabatic wall conditions. The emphasis in the study reported on in this paper was on two main areas. First, to determine the key geometric and/or flow parameters controlling the overall scaling and characteristics of both blunt and sharp fin-induced interactions. Second, to identify the conditions under which both blunt and sharp fins induced interactions have the same local scale and characteristics. (Author).
Three-dimensional Shock Wave/turbulent Boundary Layer Interaction for a 20 Degrees Sharp Fin at Mach 3
Author: B. ShapeyCharacterization of the Flowfield Near a Wrap-Around Fin at Supersonic Speeds
Author: Carl P. TilmannPublisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 166
Book Description
A wall-mounted semi-cylindrical model fitted with a single wrap- around in (WAF) has been investigated numerically and experimentally, with the objective of characterizing the mean and turbulent flowfield near a WAF in a supersonic flowfield. Numerical and experimental results are used to determine the nature of the flowfield and quantify the effects of fin curvature on the character of the flow near WAFs. This research has been motivated by the need to identify possible sources of a high-speed rolling moment reversal observed in sub-scale flight tests. Detailed mean flow and turbulence measurements were obtained in the AFIT Mach 3 wind tunnel using conventional probes and cross-wire hot-film anemometry at a series of stations upstream of and aft of the fin shock/boundary layer interaction. Hot-film anemometry results showed the turbulence intensity and Reynolds shear stress in the fuselage boundary layer to be far greater on the concave side of the fin than on the convex side. Mean flow was also obtained in the AFIT Mach 5 wind tunnel using conventional pressure probes. Numerical results were also obtained at the test conditions employing the algebraic eddy viscosity model of Baldwin and Lomax. Correlation with experimental data suggests that the calculations have captured the flow physics involved in this complicated flowfield. The calculations, corroborated by experimental results, indicate that a vortex exists in the fin/body juncture region on the convex side of the fin. This feature is not captured by the oft- used inviscid methods, and can greatly influence the pressure loading on the fin near the root.
Theoretical Investigation of 3-D Shock Wave-turbulent Boundary Layer Interactions
Author: Doyle D. KnightPublisher:
ISBN:
Category : Navier-Stokes equations
Languages : en
Pages : 80
Book Description
Theoretical Investigation of Three-Dimensional Shock Wave-Turbulent Boundary Layer Interactions. Part 4
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
A theoretical model consists of the Reynolds-averaged 3-D compressible Navier-Stokes equations, with turbulence incorporated using the algebraic turbulent eddy viscosity model of Baldwin and Lomax, This year research efforts focused on both 2-D and 3-D turbulent interactions. A theoretical model was examined for a series of separated 2-D compression corner flows at Mach 2 and 3. Calculations were performed for four separate compression corners using 2-D compressible Navier-Stodes conde with MacCormack's hybrid algorithm. Results were compared to earlier computations using the Beam-Warming algorithm, and recent experiment data for turbulent Reynolds stresses. Calculated Reynolds stresses were observed to differ significantly from experimental measurements due to the inability of the turbulence model to incorporate the multiple scale effects of the turbulence structure downstream of reattachment. Computed results using the MacCormack hybrid algorithm were observed to be insensitive to the Courant number. The 3-D turbulence interactions research concentrated on the 3-D sharp fin and on the 3-D swept compression corner. In the former case, the computed flowfield for the 20 deg sharp fin at Mach 3 and a Reynolds number of 930,000 was compared with the calculated results of Horstman (who used the Jones-Launder turbulence model) and experimental data of the Princeton Gas Dynamics Lab. Overall comparison with experiment was very good.