%0 Journal Article
%4 sid.inpe.br/mtc-m21b/2015/09.28.16.06
%2 sid.inpe.br/mtc-m21b/2015/09.28.16.06.01
%@doi 10.1016/j.piutam.2015.03.032
%@issn 2210-9838
%T Stability of compressible mixing layers modified by wakes and jets
%D 2015
%9 conference paper
%A Manco, Jhonatan Andrés Aguirre,
%A Freitas, Romulo B.,
%A Fernando, Leandro M.,
%A Mendonça, Marcio T.,
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto de Aeronáutica e Espaço (IAE)
%@affiliation Instituto de Aeronáutica e Espaço (IAE)
%@affiliation Instituto de Aeronáutica e Espaço (IAE)
%B Procedia IUTAM
%V 14
%P 129-136
%K linear stability analysis, binary free shear layers, direct numerical simulation.
%X Binary free shear layers are frequently used as a model to study the stability of flows relevant in propulsion devices. The stability behaviour of binary, compressible mixing layer have been investigated and reported in the literature by many research groups and detailed description of the stability characteristics and flow topology have been published. The stability of more complex free shear layers, such as mixing layers modified by jets and wakes, has received less attention and a smaller number of references report on the stability characteristics of such flows. The availability of advanced numerical techniques as well as computational power nowadays allow the study of complex flows by direct numerical simulation. The present investigation is an extension of previous work on the stability of complex free shear flows where besides growth rates, wave numbers and frequencies, the flow topology resulting from the interaction of mixing layers, jets and wakes are investigated. The results show that, depending on the jet or wake strength relative to the mixing layer fast and slow stream velocities, the characteristic Kelvin-Helmholtz vortices may be enhanced and a more complex vortex distribution topology results. These vorticity distributions have a significant effect on the mixture between different species on the upper and lower stream and the mixing layer to jet species ratio. The effect of three-dimensional disturbances with spanwise wavenumber β * 0 are also considered and the most amplified modes are determined for a low convective mach number condition. Different combinations of hydrogen and oxygen on the mixing layer and jets are considered. For that study the base flow is determined from a parabolic, variable properties boundary layer code. The results show that oblique disturbances are more stable than two-dimensional disturbances but with different strength depending on the particular binary free shear layer considered.
%@language en