Numerical Investigation of the Noise Emission from Serrated Nozzles in Coaxial Jets

Numerical investigation of coaxial jets entering into a hot environment

Computers & Fluids ◽

10.1016/j.compfluid.2013.07.032 ◽

2013 ◽

Vol 86 ◽

pp. 490-499 ◽

Cited By ~ 5

Author(s):

I. Klioutchnikov ◽

H. Olivier ◽

J. Odenthal

Keyword(s):

Numerical Investigation ◽

Coaxial Jets ◽

Hot Environment

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Numerical Investigation of the Coherent Structures and Sound Properties in Sonic Coaxial Jets

Advances in Applied Mathematics and Mechanics ◽

10.4208/aamm.oa-2016-0032 ◽

2017 ◽

Vol 9 (3) ◽

pp. 554-573

Author(s):

Haitao Shi ◽

Dawei Chen ◽

Pei Wang ◽

Nansheng Liu ◽

Xiyun Lu

Keyword(s):

Numerical Investigation ◽

Coherent Structures ◽

High Frequency ◽

Sound Production ◽

Recirculation Zone ◽

Decomposition Analysis ◽

Coaxial Jets ◽

Secondary Shock ◽

Eddy Simulation ◽

Annular Jet

AbstractNumerical investigation of the underexpanded sonic coaxial jets is carried out using large eddy simulation for three typical inner nozzle lip-thicknesses. Various fundamental mechanisms dictating the flow phenomena including shock structure, shear layer evolution and sound production are investigated. It is found that the inner nozzle lip induces a recirculation zone between inner and outer jets, which significantly influences the behaviors of shock structures and shear layers. The sound properties of the coaxial jets are further analyzed in detail. As the inner lip-thickness increases, the helical screech mode switches to an axisymmetric one and high-frequency screech also occurs with an oscillation frequency of recirculation zone. Based on the temporal Fourier transform and correlation analysis, the primary sources of low- and high-frequency screeches are associated with the downstream shock cells in the jet column and the secondary shock structures in the outer annular jet, respectively. The proper orthogonal decomposition analysis reveals that the dominant structures constructed by the most energetic modes shift from the downstream shock cells region to the upstream secondary shock region as the lip-thickness increases. The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to the coherent structures and sound properties in sonic coaxial jets.

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Numerical Investigation of Counter-Rotating Open Rotor Noise Emission in Different Flight Conditions

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation ◽

10.1115/gt2012-68625 ◽

2012 ◽

Cited By ~ 5

Author(s):

Eirene Rebecca Busch ◽

Manuel Keßler ◽

Ewald Krämer

Keyword(s):

Numerical Simulations ◽

Numerical Investigation ◽

Acoustic Analysis ◽

Noise Emission ◽

Rotor Noise ◽

Total Noise ◽

Open Rotor ◽

Blade Tip

Noise emission of a 9×7 and 8×8 open rotor configuration in cruise and in take-off conditions is examined by 3D unsteady numerical simulations utilising the chimera method to represent rotor movement. The acoustic analysis has been carried out with a Ffowcs Williams-Hawkings code over one rotor revolution with a resolution of 360 time steps. To ensure covering of all sources while keeping numerical losses low different hull surfaces have been examined. The comparison of two configurations at different flight conditions shows two main noise generating effects: the single rotor emission and emission caused by interaction of the rotors. The single rotor emission can mostly be seen in the rotor plane whereas the interaction can be examined at an angle of 20 to 45 and 135 to 155 degrees to the rotating axis with approximately the same share of total noise in take-off conditions. In cruise conditions the single rotor emission prevails over the interaction. This can be explained by the transonic blade tip speeds during cruise. Due to the reduced tip speeds in take-off interaction noise contributes to the total noise with a higher share than in cruise conditions. The 8×8-configuration shows higher noise emissions by interaction since the rotor-rotor interactions occur simultaneously.

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