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Nonlinear excitation of inviscid stationary vortex in a boundary-layer flow
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Duck, Peter W. Choudhari, Meelan |
| Copyright Year | 1996 |
| Description | We examine the excitation of inviscid stationary crossflow instabilities near an isolated surface hump (or indentation) underneath a three-dimensional boundary layer. As the hump height (or indentation depth) is increased from zero, the receptivity process becomes nonlinear even before the stability characteristics of the boundary layer are modified to a significant extent. This behavior contrasts sharply with earlier findings on the excitation of the lower branch Tollmien-Schlichting modes and is attributed to the inviscid nature of the crossflow modes, which leads to a decoupling between the regions of receptivity and stability. As a result of this decoupling, similarity transformations exist that allow the nonlinear receptivity of a general three-dimensional boundary layer to be studied with a set of canonical solutions to the viscous sublayer equations. The parametric study suggests that the receptivity is likely to become nonlinear even before the hump height becomes large enough for flow reversal to occur in the canonical solution. We also find that the receptivity to surface humps increases more rapidly as the hump height increases than is predicted by linear theory. On the other hand, receptivity near surface indentations is generally smaller in comparison with the linear approximation. Extension of the work to crossflow receptivity in compressible boundary layers and to Gortler vortex excitation is also discussed. |
| File Size | 946121 |
| Page Count | 24 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19960023731 |
| Archival Resource Key | ark:/13960/t3kx0bc65 |
| Language | English |
| Publisher Date | 1996-04-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Heat Transfer Nonlinear Equations Computational Fluid Dynamics Roughness Compressible Boundary Layer Boundary Conditions Three Dimensional Boundary Layer Thermodynamic Equilibrium Flow Equations Vortices Flow Distribution Inviscid Flow Cross Flow Boundary Layer Flow Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
