Numerical Simulation of Acoustic Wave Generated by the AC Arc

For the calculation of near-field acoustic waves generated by a relatively long arc, the spatial distribution of arc power density should be taken into account. An electrosound combined simulation of the ac arc was conducted. First, the arc was numerically simulated based on the 2-D MHD model. It was found that the spatial distribution of electric power density in the arc was highly nonuniform with significantly higher power density in the region close to the electrodes. Then, the acoustic wave generated by the arc was numerically simulated with the sound sources, taking the obtained distribution of arc power density into account. It was found that dP/dt, the derivative of arc power, was an important parameter that determined the sound pressure. The waveform of sound pressure was exactly of the same shape as that of dP/dt and the amplitude of sound pressure was proportional to that of dP/dt. The acoustic wave obtained by the simulation agreed well with the experimentally measured one. The dependence of the wave pressure on the propagating distance was compared to that of the spherical wave based on a monopole sound source, which confirmed the necessity of the electrosound combined simulation.