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

• Published in: Computer physics communications 1991-01, Vol.65 (1), p.201-208
• Main Author: Macaraeg, Michéle G.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fluid Mechanics And Heat Transfer; Mathematical methods in physics; Numerical approximation and analysis; Physics
• ISSN: 0010-4655; 1879-2944
• DOI: 10.1016/0010-4655(91)90172-H

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 ( u 2) to roughly 1 5 the speed of the high speed side ( u 1), 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 u 2 is increased. The wave direction of maximum growth for u 2 > 0.4 is found to be the direction of the faster stream ( u 1) over a broad range of transverse velocities.