2 edition of Görtler vortices and transition in wall boundary layers of two Mach 5 nozzles found in the catalog.
Görtler vortices and transition in wall boundary layers of two Mach 5 nozzles
Ivan E Beckwith
by National Aeronautics and Space Administration, Scientific and Technical Information Branch, For sale by the National Technical Information Service] in Washington, D.C, [Springfield, Va
Written in English
|Statement||Ivan E. Beckwith and Barbara B. Holley|
|Series||NASA technical paper -- 1869|
|Contributions||Holley, Barbara B, Langley Research Center, United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch|
|The Physical Object|
|Pagination||69 p. :|
|Number of Pages||69|
Gortler vortices develop in boundary layer flows over concave surfaces due to the imbalance between centrifugal forces and the wall-normal pressure gradient. These vortices can be efficient precursors to transition in boundary layers exposed to free-stream disturbance or surface non-uniformities, because they can alter the mean flow causing the. An experimental and numerical study of roughness-induced instabilities in a mach boundary layer. In: RTO AVT RSM Specialists’ Meeting on Hypersonic Laminar-Turbulent Transition, NFL () Google Scholar.
Abstract. Boundary-layer transition is a problem that has plagued several generations of aerodynamicists. There are very few things about transition that are known with certainty, other than the fact that it happens if the Reynolds number is large by: Otherwise, for a nozzle with a large length, it will lead to two troubles: one is the increased difficulty in the machining of the inner surface and the other is the easier transition in the boundary layer on the nozzle wall cause by T-S : Ruiqu Li, Junmou Shen, Jian Gong.
Title: The onset of Görtler vortices in laminar boundary layer flow over a slightly concave wall: Authors: Kim, Min Chan; Choi, Chang Kyun; Yoon, Do-Young: Publication: European Journal of Mechanics - B/Fluids, vol. 29, issue 6, pp. Smith, “ A synthesized model of the near-wall behavior in turbulent boundary layers,” in Proceedings of the 8th Symposium on Turbulence, edited by J. Zakin and G. Patterson (University of Missouri-Rolla, ), pp. – describes both the kinematics and dynamics of hairpin vortices and their relationships to low-speed streaks, the.
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The onset of transition in the wall boundary layers of two axisymmetric Mach 5 wind-tunnel nozzles has been measured under conditions of extremely low incident disturbance levels. The range of test unit Reynolds numbers, based on conditions at the nozzle exit, was from 6 x 10 to the 6th power m to x 10 to the 7th power m.
Görtler vortices and transition in wall boundary layers of two Mach 5 nozzles. Washington, D.C.: National Aeronautics and Space Administration, Scientific and.
possible role of Gortler vortices in transition of the nozzle-wall boundary layers of two Mach 5 nozzles. One of these nozzles is usually referred to as the conventional nozzle and the other as the slotted, rapid-expansion, and/or electroformed nozzle.
Detailed data on the mean properties of the free-stream. Görtler vortices and transition in wall boundary layers of two Mach 5 nozzles / By Ivan E. Beckwith, Barbara B. Holley, United States. National Aeronautics and Space Administration. By employing a nanoparticle-based planar laser scattering technique, with inflow Mach number ofboundary layers formed over two concave walls with respective curvature radii of and mm are visualized.
The formation and the breakup process of the Görtler vortices have been clearly captured, which has seldom been done before under the supersonic by: 4.
The laminar-turbulent transition process has been documented in a concave-wall boundary layer subject to low (%) free-stream turbulence intensity.
Transition began at a Reynolds number, Re x (based on distance from the leading edge of the test wall), of ×10 5 and was completed by ×10 by: 1.
Nozzle Wall Boundary-Layer Transition and Freestream Disturbances at Mach 5. Instabilities and transition in the wall boundary layers of low-disturbance supersonic nozzles. SILER; 17 August Mean flow and noise measurements in a Mach pilot quiet by: Stability of Gortler Vortices in Boundary Layers.
Boundary layer transition over a concave surface caused by centrifugal instabilities. Computers & Fluids, Vol. Linear Stability of the Supersonic Turbulent Boundary Layer to Görtler Vortices on a Concave by: The linear amplification of both Tollmien-Schlichting (TS) and Görtler type instabilities was calculated for the wall boundary layers in this Mach pilot nozzle.
By using an e N method, it was determined that amplified Görtler vortices were involved in the transition process. The resulting transition criteria were then applied to several Cited by: The role of Görtler vortices in the hypersonic boundary layer transition. Spatial optimal growth of Görtler vortices in two-dimensional compressible boundary layers.
Jean-Michel Lucas, Nonlinear Transient Growth and Boundary Layer Transition. Pedro Paredes. the engine inlet on scramjet vehicles Onset of transition along the tunnel walls leads to a substantial increase in the levels of free-stream disturbances encountered by wind tunnel models, compromising one’s ability to simulate in-flight transition behavior on the models.
On the other hand, it is desirable for the boundary layer to becomeCited by: Görtler vortices developed in laminar boundary layer experience remarkable changes when the flow is subjected to compressibility effects. In the present study, five Ma numbers, covering.
Vortices would then develop in a growing boundary layer on the inner wall of the outer cylinder.(46'1') Similar vortices have been observed on inner walls of supersonic nozzles at Mach numbers 5"6) and (17) These results are qualitative and provide no details that could be used for verification of the theoretical predictions.
Cited by: Liepmann investigated the transition of the boundary layer flow from the laminar to the turbulent region experimentally. He reported the effect of curvature, pressure gradient and free stream turbulence on the transition position.
His experimental results for the large radius of curvature (R = 20 ft), the zero pressure gradient and the low turbulence level (%) are compared with the present Cited by: 7. Hypersonic boundary layer transition on a concave wall: Stationary Görtler vortices Article (PDF Available) in Journal of Fluid Mechanics April with Reads How we measure 'reads'.
Linear theory is used to analyze the stability of two‐dimensional boundary layer flows to stationary Görtler vortices. The basic flow profiles in the boundary layer are described by the Falkner–Skan similarity solutions.
We approach the problem both with local linear theory (with the streamwise position held fixed) and with a streamwise marching technique (to represent the evolution of Cited by: Secondary instabilities of Görtler vortices in the centrifugal instability of a boundary layer over a concave wall, arises due to the imbalance between the centrifugal force and the wall-normal pressure gradient.
Streamwise-oriented, counter-rotating vortices (Görtler recognized as a key factor leading the boundary layer to transition. The Görtler vortices tend to move towards the boundary-layer core when the flow is more stable, i.e. as the frequency or the Mach number increase, or when the curvature decreases.
The Gröwth of Gortler vortices in boundary layers on concave walls is investigated. It is shown that for vortices of wavelength comparable to the boundary-layer thickness the appropriate linear stability equations cannot be reduced to ordinary differential by: On the Görtler Vortex Instability Mechanism at Hypersonic Speeds Laminar-Turbulent Transition, IUTAM Symposium Görtler Vortices and Transition in Wall Boundary Layers of Two Mach 5 Nozzles.
Görtler vortices in subsonic and moderate supersonic flows (Ma =and ) are governed by the conventional wall-layer mode (mode W). In hypersonic flows (Ma =), the trapped. Competition of multiple Görtler modes in hypersonic boundary layer flows are investigated with the local and marching methods.
The wall-layer mode (mode W) and the trapped-layer mode (mode T) both occur in the compressible boundary layer where there exists a temperature adjustment layer near the upper edge. The mode T has the largest growth rate at a lower Görtler Cited by: Centripetal instabilities in two flows involving time-dependent Rayleigh layers on a rotating circular cylinder are examined.
In one case we consider the stability of the flow induced in an infinite expanse of quiescent fluid when the cylinder is impulsively given a constant angular velocity; in the other problem the angular velocity increases as the square root of time so that the undisturbed Cited by: