Jet noise from instability mode interactions

Sandham, Neil D., Salgado, Adriana M. and Agarwal, Anurag (2008) Jet noise from instability mode interactions. In, 14th AIAA/CEAS Aeroacoustics Conference, Vancouver, Canada, 05 - 07 May 2008. 12pp.


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A nonlinear interaction model is used to study sources of sound in jets. The model uses quadratic interactions of instability modes, which are obtained by solving the linear parabolized stability equations. Source terms involving nonlinear interactions are evalu-
ated and a linear wave equation is solved with direct injection of the source terms. Thus the complete method solves only linear partial differential equations, coupled by nonlinear source terms. It allows the contribution of each modal interaction to be studied separately, giving a breakdown of the radiation pattern of each interaction. The method is demonstrated using a fixed base flow matched to the experiment of Stromberg et al. (J. Fluid Mech. 72(2), 1980). The squared streamwise velocity quadrupole is the largest source term for axisymmetric mode interactions, while for helical-helical mode interactions both the squared radial and squared azimuthal velocities are the main contributing sources, despite a strong cancelation effect between them. Results are also presented for an alternative implementation, in which the base flow is allowed to vary according to the Reynolds stresses of the developing instability modes. This model demonstrates sound production during mode growth and subsequent saturation.

Item Type: Conference or Workshop Item (Paper)
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Keywords: jet noise, weakly nonlinear model
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TL Motor vehicles. Aeronautics. Astronautics
Divisions : University Structure - Pre August 2011 > School of Engineering Sciences
University Structure - Pre August 2011 > School of Engineering Sciences > Aerodynamics & Flight Mechanics
University Structure - Pre August 2011 > Institute of Sound and Vibration Research
ePrint ID: 64135
Accepted Date and Publication Date:
6 May 2008Published
Date Deposited: 02 Dec 2008
Last Modified: 31 Mar 2016 12:48

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