High-frequency wavepackets in turbulent jets

Autor(es)

Sasaki, Kenzo ^[1] ; Cavalieri, Andre V. G. ^[1] ; Jordan, Peter ^[2] ; Schmidt, Oliver T. ^[3] ; Colonius, Tim ^[3] ; Bres, Guillaume A. ^[4]

Afiliação do(s) autor(es)

^[1] Inst Tecnol Aeronaut, Aerodynam Dept, BR-12228900 Sao Jose Dos Campos - Brazil

^[2] Inst Pprime, Dept Fluides Therm & Combust, F-86036 Poitiers - France

^[3] CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 - USA

^[4] Cascade Technol Inc, Palo Alto, CA 94303 - USA

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF FLUID MECHANICS; v. 830, NOV 2017.
• Citações Web of Science: 10

Resumo

Wavepackets obtained as solutions of the flow equations linearised around the mean flow have been shown in recent work to yield good agreement, in terms of amplitude and phase, with those educed from turbulent jets. Compelling agreement has been demonstrated, for the axisymmetric and first helical mode, up to Strouhal numbers close to unity. We here extend the range of validity of wavepacket models to Strouhal number St = 4.0 and azimuthal wavenumber m = 4 by comparing solutions of the parabolised stability equations with a well-validated large-eddy simulation of a Mach 0.9 turbulent jet. The results show that the near-nozzle dynamics can be correctly described by the homogeneous linear model, the initial growth rates being accurately predicted for the entire range of frequencies and azimuthal wavenumbers considered. Similarly to the lower-frequency wavepackets reported prior to this work, the high-frequency linear waves deviate from the data downstream of their stabilisation locations, which move progressively upstream as the frequency increases. (AU)

• Processo FAPESP: 16/25187-4 - Controle de escoamento utilizando as equações de estabilidade parabolizadas
• Beneficiário: Kenzo Sasaki
• Modalidade de apoio: Bolsas no Brasil - Doutorado