Receptivity Of Hypersonic Non Gradient Boundary Layer To Wall Disturbances

Download or read book Receptivity of Hypersonic Non-Gradient Boundary Layer to Wall Disturbances written by Alexander Fedorov and published by . This book was released on 1999 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical analysis of hypersonic boundary-layer receptivity to wall disturbances is conducted using a combination of asymptotic and numerical methods. Excitation of the second-mode waves by distributed and local forcing on the flat plate surface is studied under adiabatic and cooled wall conditions. Analysis addresses receptivity to wall vibrations, periodic suction-blowing through a hole or slot, and temperature disturbances. A strong excitation occurs in local regions where forcing is in resonance with normal waves. It is revealed that the receptivity function tends to infinity as the resonance point tends to the branch point of discrete spectrum that is typical for the cooled wall case. Asymptotic analysis resolves this singularity and provides maximal receptivity levels in the branch-point vicinity. Analytical results are integrated into the computational module providing fast estimates of receptivity levels for different types and shapes of wall forcing. Numerical results indicate extremely high receptivity to vibrations and suction-blowing near the lower neutral branch. Critical amplitudes of local and distributed vibrations are estimated for bypass of the linear stability phase. The theoretical model can be used to predict initial amplitudes of unstable waves in active (ascending) flights accompanied by skin vibrations.