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Effect of leading-edge geometry on boundary-layer receptivity to freestream sound
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Saric, W. S. Lin, Nay Reed, Helen L. |
| Copyright Year | 1991 |
| Description | The receptivity to freestream sound of the laminar boundary layer over a semi-infinite flat plate with an elliptic leading edge is simulated numerically. The incompressible flow past the flat plate is computed by solving the full Navier-Stokes equations in general curvilinear coordinates. A finite-difference method which is second-order accurate in space and time is used. Spatial and temporal developments of the Tollmien-Schlichting wave in the boundary layer, due to small-amplitude time-harmonic oscillations of the freestream velocity that closely simulate a sound wave travelling parallel to the plate, are observed. The effect of leading-edge curvature is studied by varying the aspect ratio of the ellipse. The boundary layer over the flat plate with a sharper leading edge is found to be less receptive. The relative contribution of the discontinuity in curvature at the ellipse-flat-plate juncture to receptivity is investigated by smoothing the juncture with a polynomial. Continuous curvature leads to less receptivity. A new geometry of the leading edge, a modified super ellipse, which provides continuous curvature at the juncture with the flat plate, is used to study the effect of continuous curvature and inherent pressure gradient on receptivity. |
| File Size | 739976 |
| Page Count | 20 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19920005752 |
| Archival Resource Key | ark:/13960/t4mm17g26 |
| Language | English |
| Publisher Date | 1991-12-01 |
| Access Restriction | Open |
| Subject Keyword | Aerodynamics Navier-stokes Equation Incompressible Flow Sound Waves Laminar Boundary Layer Flat Plates Finite Difference Theory Tollmien-schlichting Waves Free Flow Curvature Leading Edges Spherical Coordinates Pressure Gradients Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
