Investigation of supersonic modes and three-dimensionality in bounded, free shear flows

✍ Scribed by Michéle G. Macaraeg

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 498 KB
• Volume: 65
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/0010-4655(91)90172-h

✦ Synopsis

It is found through two-dimensional temporal simulations of high-speed free shear layers that mean flow distortion is significantly increased when supersonic disturbances are introduced as initial conditions. The shear layer exhibits no subharmonic growth or roll-up, but rather a spectral broadening as energy is distributed into higher harmonics. Increasing the velocity of one side of the mixing layer (u2) to roughly 1/5 the speed of the high speed side (Ul), allows a slight subharmonic growth at a very slow rate for two-dimensional modes. A first look at three-dimensional free shear flows is also presented for M = 2. No effect is seen for incompressible flow; however, stabilization is seen with respect to maximum temporal growth rates as the transverse velocity is increased. A much stronger, but similar effect is seen if u2 is increased. The wave direction of maximum growth for u 2 > 0.4 is found to be the direction of the faster stream (ul) over a broad range of transverse velocities.