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.