Low-speed boundary-layer transition workshop

  • 48 Pages
  • 0.68 MB
  • English
Rand , Santa Monica
Boundary layer -- Congr
SeriesRand report -- R-1752-ARPA/ONR, R (Rand Corporation) -- R-1752-ARPA/ONR
ContributionsRand Corporation, United States. Defense Advanced Research Projects Agency, United States. Office of Naval Research
The Physical Object
Paginationix, 48 p. ;
ID Numbers
Open LibraryOL18095722M

"This report has been prepared to document the Low-Speed Boundary-Layer Transition Workshop held at the offices of the Rand Corporation July"--Preface.

"A report prepared for Defense Advanced Research Projects Agency and Office of Naval Research.". Low-speed Boundary-layer Transition Workshop (2nd: Santa Monica, Calif.). Proceedings of [the] Low-speed Boundary-layer Transition Workshop: II.

Santa Monica: Rand Corporation, (OCoLC) Material Type: Conference publication: Document Type: Book: All Authors / Contributors: William S King; Mari Yokota; Rand Corporation.

Low Reynolds number turbulence models. In the low Reynolds number turbulence models, the wall damping functions are modified in order to capture the transition effects [].To be able to predict the transition onset, these models depend on the diffusion of the turbulence from freestream into the boundary layer and its interaction with the source terms of the turbulence Cited by: 2.

To summarize, the aim and concern of this chapter is to introduce the reader in the Low-speed boundary-layer transition workshop book field of the low speed turbulent boundary layer wind tunnels, turbulent boundary layer flows, coherent structures, flow control passive and active devices, action upon airfoils and wings, and wind engineering phenomena in : Jorge Colman Lerner, Ulfilas Boldes, Julio Marañón Di Leo, Juan Sebastián Delnero.

Low-speed boundary-layer transition workshop [] King, William S. Santa Monica: Rand, Part V: Numerical Methods in Boundary Layer Theory.

(source: Nielsen Book Data) Numerical study of compressible boundary-layer transition between two concentric cylinders. The direct numerical simulation of boundary layer transition over a 5° half-cone-angle blunt cone is performed.

The free-stream Mach number is 6 and the angle of attack is 1°. The boundary layer is a very thin layer of air lying over the surface of the wing and, for that matter, all other surfaces of the airplane.

Because air has viscosity, this layer of air tends to adhere to the wing. As the wing moves forward through the air, the boundary layer at first flows smoothly over the streamlined shape of the airfoil.

Transition and Stability of High-Speed Boundary Layers Article in Annual Review of Fluid Mechanics 43(1) January with 88 Reads How we measure 'reads'. Full text of "Minnowbrook II Workshop on Boundary Layer Transition in Turbomachines" See other formats. Power, L.: A Comparison Between Measured Low-speed boundary-layer transition workshop book Computed Locations of Transition on Nine Forebodies of Revolution.

Proceedings of Low-Speed Boundary Layer Transition Workshop, II, Rand Corporation Report R-P, (Eds.: W. King and M. Yokota). Google ScholarCited by:   This movie presents a full set of images from a wind tunnel test combined in an animation. In the test, the 65° delta wing model of mm length and mm span was tested in subsonic wind tunnel at constant flow speed of 50 m/s and varying the angle of attack.

Boundary layer profiles at S = in. the adverse pressure gradient is obviously a very important transition factor as will be seen in Fig. 8 for cases 2, 3 and 4, which correspond to different pressure gradients. Transition is not complete until the boundary layer profile is of theFile Size: 6MB.

These two volumes contain the proceedings of the workshop on the Institute for Computer Instability and Transition, sponsored by Applications in Science and Engineering (ICASE) and the Langley Research Center (LaRC), during May 15 to June 9, The work­ shop coincided with the initiation of a.

transition and crossflow evolution in the context of a hypersonic boundary-layer flow is a circular cone at small but nonzero angle of attack [5, 6]. Even though a number of experimental studies pertaining to circular cone transitionCited by: boundary-layer transition beneath periodic passing wakes.

In this case, long streaks are precluded by the finite width of the wake; however, the breakdown into turbulent spots is still associated to low-speed regions (‘backward jets’) located in the upper part of the boundary layer. The basic problems of transition in both incompressible and compressible boundary layers are reviewed.

Flow structures in low-speed transitional and developed turbulent boundary layers are presented, together with almost all of the physical mechanisms that have been proposed for their formation.

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dimensional supersonic boundary layer (Jiang et al. ; Mayer et al. ) or the transition due to secondary instabilities of Tollmien-Schlichting waves in a low-speed at plate boundary layer (Sayadi et al.

In terms of cross ow-induced transition in a three-dimensional boundary layer, the present authors (Choudhari et al. ; Duan. The studies were conducted on both low-speed and high-speed experimental facilities under the unsteady flow conditions with upstream passing wakes.

Workshop on Boundary Layer Transition in Turbomachines, Syracuse University. Investigation of the Effectiveness of Various Types of Boundary Layer Transition Elements of Low Reynolds Cited by: turbulent boundary layer • Transition takes place after a laminar separation of the boundary layer.

• Leads to a very rapid growth of disturbances and to transition.

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Modelling Laminar - Turbulent Transition Processes Author: Gilles Eggenspieler, Ph.D. Created Date:File Size: 2MB. This paper is a short review of our recent DNS work on physics of late boundary layer transition and turbulence. Based on our DNS observation, we propose a new theory on boundary layer transition, which has five steps, that is, receptivity, linear instability, large vortex structure formation, small length scale generation, loss of symmetry and randomization to by: 4.

In the interest of being able to predict separating–reattaching flows, it is necessary to have an accurate model of transition in separation bubbles. An experimental investigation of the process of turbulence development in a separation bubble shows Cited by: Helical modes in boundary layer transition Abstract Observations are presented to show that in an adverse pressure gradient boundary layer, beneath free-stream turbulence, the interaction between Klebanoff streaks and naturally arising instability waves leads to helical disturbances which break down to form turbulent by: 6.

during which the boundary layer is in turbulent state compared to the complete period of observation. It means that Γ is equal to 0 when the boundary layer is laminar and becomes 1 when the boundary layer is turbulent. The advancement of the transition process is therefore quantitatively represented by the variation of Γ along the profile.

The objectives of the workshop were to (i) expose the academic community to current technologically important issues of instability and transition in shear flows over the entire speed range, (ii) acquaint the academic com­ munity with the unique combination of theoretical, computational and experimental capabilities at LaRC and foster.

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ematical models to predict transition. With this research, designers are better equipped to predict and control transition, leading to more efficient turbine blade designs.

Figure 2: Schematic of the tow-tank apparatus Figure 3: Shear-layer roll-up with K-H vortex pairing x/c – Effect of crossflow instability on transition in three. Wadhams T, MacLean M, Holden M. Recent experimental studies of high-speed boundary-layer transition in LENS facilities to further the development of predictive tools for boundary layer transition in flight.

PaperAIAA, January Cited by: The effects of convex curvature on boundary layer transition were examined experimentally in low and high free-stream turbulence, and in zero and favorable pressure gradients. For high turbulence with zero pressure gradient, transition along convex surfaces was found to be similar to that on flat surfaces, however at low turbulence levels.

18 A boundary-layer profile is the shape of the variation of a boundary-layer characteristic like local velocity or tempera- ture with height above the surface.

19 M.R. Head, D. Johnson, and M. Coxon, Flight Experiments on Boundary-Layer Control for Low Drag (BritishFile Size: 2MB. Abstract: Description.

Relevant to aerospace, mechanical, and civil engineers, Boundary Layer Analysis, Second Edition spans the entire range of viscous fluid flows of engineering interest - from low-speed to hypersonic flows - introducing and analyzing laminar, transitional, and turbulent flows; the physics of turbulent shear flows; and turbulence models.

Spanning the entire range of viscous fluid flows of engineering interest - from low-speed to hypersonic flows - this volume introduces and analyzes turbulent flows, the physics of turbulent shear flows, and turbulence models.

It covers older analytical methods which are widely used in preliminary design, especially for design optimization Cited by:. Trains with different numbers of cars running in the open air were simulated using the delayed detached-eddy simulation (DDES).

The numbers of cars included in the simulation are 3, 4, 5 and 8. The aim of this study was to investigate how train length influences the boundary layer, the wake flow, the surface pressure, the aerodynamic drag and the friction by: 2.APA/FD Low Speed, Low Reynolds Number Aerodynamics • Friday, 17 June • hrs.The influence of wind turbine airfoil trailing edge thickness on aerodynamics and aerodynamic noise characteristics was studied using the computational fluid dynamics (CFD)/ Ffowcs Williams–Hawkings (FW–H) method in the present work.

First, the airfoil of a DUWflatback airfoil was chosen as the research object, and numerical method validation was Cited by: 5.