by National Aeronautics and Space Administration, Langley Research Center in Hampton, Va .
Written in English
|Series||NASA contractor report -- 172370, ICASE report -- no. 84-17|
|Contributions||Langley Research Center, Institute for Computer Applications in Science and Engineering|
|The Physical Object|
In swept-wing flows the Görtler mechanism is probably not present for typical angles of sweep of about 20°.Some discussion of the receptivity problem for vortex instabilities in weakly three-dimensional boundary layers is given; it is shown that inviscid modes have a coupling coefficient marginally smaller than those of the fastest growing Cited by: In swept-wing flows the Görtler mechanism is probably not present for typical angles of sweep of about 20°. Some discussion of the receptivity problem for vortex instabilities in weakly three-dimensional boundary layers is given; it is shown that inviscid modes have a coupling coefficient marginally smaller than those of the fastest growing. The linear instability of the hypersonic boundary layer on a curved wall is considered. As a starting point real-gas effects are ignored and the viscosity of the fluid is taken to be related to the temperature either by Chapman’s Law or by Sutherland’s Law. It is shown that the flow is susceptible to Görtler Cited by: The origins of transition to turbulence in a bounded shear flow within a low disturbance environment are typically found in the instabilities of the basic state. There are, of coursc, a number of mcchanisms that can lead to breakdown of laminar boundary-layer flow and many have been reviewed in these Volumes, e.g. inflectional profiles and viscous instabilities (Reshotko , Bayly et al
On the Görtler Vortex Instability Mechanism at Hypersonic Speeds. Stability of Three-Dimensional Boundary Layers. 1 October Görtler instability of boundary layers over concave and convex walls. Physics of Fluids, Vol. 29, No. 8. Hall, “ The Görtler vortex instability mechanism in three-dimensional boundary layers,” Proc. R. Soc. London Ser. A , (). Google Scholar Crossref. The mechanism that gives rise to this instability is fully consistent with the mechanisms described by Rayleigh () and is the same that originates the Taylor instability (usually associated with the flow between rotating concentric cylinders) and the Görtler instabilities (observed in the flow over a concave surface (Görtler, )). Görtler instability occurs due to the action of centrifugal forces in boundary layers over curved surfaces, where it most commonly results in the generation of steady streamwise vortices. This study provides a summary of the current knowledge of this phenomenon. All existing experimental evidence is discussed.
The Goertler vortex instability mechanism in three. Otto S.R. () On the Secondary Instability of Görtler Vortices in Three-Dimensional Boundary Layers. In: Duck P.W., Hall P. (eds) IUTAM Symposium on Nonlinear Instability and Transition in Three-Dimensional Boundary Layers. In fluid dynamics, Görtler vortices are secondary flows that appear in a boundary layer flow along a concave wall. If the boundary layer is thin compared to the radius of curvature of the wall, the pressure remains constant across the boundary layer. On the other hand, if the boundary layer thickness is comparable to the radius of curvature, the centrifugal action creates a pressure variation. The two-dimensional boundary layer on a concave wall is centrifugally unstable with respect to vortices aligned with the basic flow for sufficiently high values of the Goertler number. However, in most situations of practical interest the basic flow is three-dimensional and previous theoretical investigations do not apply. The linear stability of the flow over an infinitely long swept wall of.