Prediction of the onset of sound amplification at shear layers using linear stability analysis

• A simple numerical technique for predicting the potentiality of sound amplification by shear layers is presented. The technique applies Howe’s energy corollary to describe the energy exchange between the vortical mode in the shear layer and the acoustic wave incident on the layer. Potential sound amplification by the vortical mode is identified when the net energy gain of the incident acoustic wave is positive. The technique only requires steady flow simulation and linear stability analysis so the computational cost is modest. Numerical results are compared with a measurement on a particle agglomeration pipe and it shows that the sound amplification can be satisfactorily predicted by the simple technique.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Keyword

Acoustic waves

Aeroacoustics

Linear stability analysis

Shear flow

A-particles

Computational costs

Energy exchanges

Net energy gains

Numerical results

Numerical techniques

Sound amplification

Vortical modes

Amplification

Publication and Content Type

ref (subject category)

kon (subject category)