Boundary Layer Receptivity
Download Boundary Layer Receptivity full books in PDF, epub, and Kindle. Read online free Boundary Layer Receptivity ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Author | : Mohsen Jahanmiri |
Publisher | : LAP Lambert Academic Publishing |
Total Pages | : 64 |
Release | : 2013 |
Genre | : |
ISBN | : 9783659364518 |
Receptivity is the process which describes how environmental disturbances (such as gusts, acoustic waves or wall roughness) are filtered by a boundary layer and turned into downstream growing waves. It is closely related to the identification of initial conditions for the disturbances and requires knowledge of the characteristics of the specific external forcing field. Due to important role of receptivity theory in transition process of boundary layers, quite a few research works have been carried out in past few decades. This research review report tries to highlight the major research activities in this field of study that includes: the theory, different types of receptivity, its effect in three-dimensional boundary layers and receptivity at high speeds.
Author | : Edward J. Kerschen |
Publisher | : |
Total Pages | : |
Release | : 1989 |
Genre | : |
ISBN | : |
Author | : C. E. Grosch |
Publisher | : |
Total Pages | : 6 |
Release | : 1981 |
Genre | : Turbulent boundary layer |
ISBN | : |
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : 44 |
Release | : 1995 |
Genre | : Boundary layer |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 20 |
Release | : 1993 |
Genre | : |
ISBN | : |
Receptivity processes by which free-stream disturbances generate Tollmien-Schlichting waves in boundary layers have been analyzed using asymptotic methods for high Reynolds numbers. Vortical and acoustic free-stream disturbances have been considered. Receptivity occurs in the vicinity of the leading edge, and in localized regions further downstream where some feature (e. g., a wall hump) produces a short-scale disturbance to the mean flow. Nonlinear effects related to the free-stream pressure field have been found to play an important role in localized receptivity to vortical disturbances. For leading- edge receptivity, the influences of the body nose radius and aerodynamic loading in the leading-edge region have been analyzed. In the absence of aerodynamic loading, an increase in the body nose radius decreases the leading-edge receptivity coefficient. However, strong aerodynamic loading leads to a dramatic increase in the leading-edge receptivity coefficient, negating the decrease due to a larger nose radius. The propagation of an instability wave past a junction between a rigid wall and a surface with non-zero compliance or admittance has also been analyzed. The junction can cause energy to be scattered from the instability wave to higher eigenmodes, effectively attenuating the instability wave.
Author | : William S. Saric |
Publisher | : |
Total Pages | : 246 |
Release | : 1996 |
Genre | : Boundary layer |
ISBN | : |
Experiments are conducted in the Arizona State University Unsteady Wind Tunnel to investigate acoustic receptivity in the leading-edge region of a Blasius boundary layer. The experiment utilizes two different flat-plate models. One model has a leading edge with a special geometry that limits the receptivity mechanism to the leading edge. The second model is a tapered elliptical-leading-edge flat plate with a junction. A Blasius basic state isolates the instability mechanism to a Tollmien-Schlichting wave and symmetric flow around the leading edge is established for each model. The acoustic disturbances are digitally generated and broadcast into the test section creating sound pressure levels ranging from 90 to 130 dB. Several techniques are examined for separating the Tollmien-Schlichting wave from the background noise. These include hot-wire signal separation in the complex plane, the Kendall differential microphone, a multiple-microphone technique, and a sound burst technique. Receptivity coefficients show the same focusing characteristics of the T-S wave amplitude for a narrow band of frequencies documented in previous experiments. This suggests that the focusing behavior is not due to the special geometry of tl0e leading edge. Boundary-layer measurements indicate some spanwise variation that could contribute to the focusing behavior. The work is now extended to include very high disturbance levels.
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : 21 |
Release | : 1990 |
Genre | : |
ISBN | : |
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : |
Release | : 1994 |
Genre | : |
ISBN | : |
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : 36 |
Release | : 1992 |
Genre | : Boundary layer |
ISBN | : |
Author | : Meelan Choudhari |
Publisher | : |
Total Pages | : 40 |
Release | : 1994 |
Genre | : Boundary layer |
ISBN | : |