On Nonlinear Tollmien-Schlichting/vortex Interaction in Three Dimensional Boundary Layers
Author : Dominic A. R. Davis
Publisher :
Page : 32 pages
File Size : 39,86 MB
Release : 1993
Category : Eddies
ISBN :
Author : Dominic A. R. Davis
Publisher :
Page : 32 pages
File Size : 39,86 MB
Release : 1993
Category : Eddies
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Author : P. Hall
Publisher :
Page : 44 pages
File Size : 28,13 MB
Release : 1988
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Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 30 pages
File Size : 16,49 MB
Release : 2018-07-09
Category :
ISBN : 9781722451806
The instability of an incompressible three-dimensional boundary layer (that is, one with cross-flow) is considered theoretically and computationally in the context of vortex/wave interactions. Specifically the work centers on two low amplitude, lower-branch Tollmien-Schlichting waves which mutually interact to induce a weak longitudinal vortex flow; the vortex motion, in turn, gives rise to significant wave-modulation via wall-shear forcing. The characteristic Reynolds number is taken as a large parameter and, as a consequence, the waves' and the vortex motion are governed primarily by triple-deck theory. The nonlinear interaction is captured by a viscous partial-differential system for the vortex coupled with a pair of amplitude equations for each wave pressure. Three distinct possibilities were found to emerge for the nonlinear behavior of the flow solution downstream - an algebraic finite-distance singularity, far downstream saturation or far-downstream wave-decay (leaving pure vortex flow) - depending on the input conditions, the wave angles, and the size of the cross-flow. Davis, Dominic A. R. and Smith, Frank T. Glenn Research Center NCC3-233; RTOP 505-62-21...
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 42 pages
File Size : 11,22 MB
Release : 2018-07-13
Category :
ISBN : 9781722908577
The weakly nonlinear interaction of oblique Tollmien-Schlichting waves and longitudinal vortices in compressible, high Reynolds number, boundary-layer flow over a flat plate is considered for all ranges of the Mach number. The interaction equations comprise of equations for the vortex which is indirectly forced by the waves via a boundary condition, whereas a vortex term appears in the amplitude equation for the wave pressure. The downstream solution properties of interaction equations are found to depend on the sign of an interaction coefficient. Compressibility is found to have a significant effect on the interaction properties; principally through its impact on the waves and their governing mechanism, the triple-deck structure. It is found that, in general, the flow quantities will grow slowly with increasing downstream co-ordinate; i.e. in general, solutions do not terminate in abrupt, finite-distance 'break-ups'. Blackaby, Nicholas D. Unspecified Center NAS1-19480; RTOP 505-90-52-01...
Author : Institute for Computer Applications in Science and Engineering
Publisher :
Page : 60 pages
File Size : 10,80 MB
Release : 1989
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ISBN :
Author : Institute for Computer Applications in Science and Engineering
Publisher :
Page : 40 pages
File Size : 14,57 MB
Release : 1988
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Author :
Publisher :
Page : 44 pages
File Size : 44,3 MB
Release : 1987
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ISBN :
Author : P. Hall
Publisher :
Page : 44 pages
File Size : 48,81 MB
Release : 1987
Category : Fluid mechanics
ISBN :
Author : National Aeronautics and Space Adm Nasa
Publisher : Independently Published
Page : 62 pages
File Size : 44,17 MB
Release : 2018-10-29
Category :
ISBN : 9781729393697
There are many fluid flows where the onset of transition can be caused by different instability mechanisms which compete among themselves. The interaction is considered of two types of instability mode (at an asymptotically large Reynolds number) which can occur in the flow above a rotating disc. In particular, the interaction is examined between lower branch Tollmien-Schlichting (TS) waves and the upper branch, stationary, inviscid crossflow vortex whose asymptotic structure has been described by Hall (1986). This problem is studied in the context of investigating the effect of the vortex on the stability characteristics of a small TS wave. Essentially, it is found that the primary effect is felt through the modification to the mean flow induced by the presence of the vortex. Initially, the TS wave is taken to be linear in character and it is shown (for the cases of both a linear and a nonlinear stationary vortex) that the vortex can exhibit both stabilizing and destabilizing effects on the TS wave and the nature of this influence is wholly dependent upon the orientation of this latter instability. Further, the problem is examined with a larger TS wave, whose size is chosen so as to ensure that this mode is nonlinear in its own right. An amplitude equation for the evolution of the TS wave is derived which admits solutions corresponding to finite amplitude, stable, traveling waves. Bassom, Andrew P. and Hall, Philip Unspecified Center...
Author : Philip Hall
Publisher :
Page : 44 pages
File Size : 33,23 MB
Release : 1989
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ISBN :