In this paper we study the generation and behavior of subharmonics in a bubbly liquid confined in an acoustic resonator, through numerical simulations carried out at finite-amplitude acoustic pressure. Several configurations in terms of resonator length and driving frequency are considered here. Our results show that these frequency components, created from a higher-frequency signal at the source (ultrasound), are due to the nonlinearity of the medium at high acoustic-pressure amplitude and to the configuration of the resonator (geometry and boundaries). We also show that they have an amplitude-threshold dependence, which is in concordance with the literature. The response of these subharmonics to different sequences of pressure amplitudes also reveals the hysteretic nature of the bubbly liquid.

在本文中，我们通过在有限振幅声压下进行的数值模拟，研究了限制在声谐振器中的气泡液体中次谐波的产生和行为。这里考虑了谐振器长度和驱动频率方面的几种配置。我们的结果表明，这些频率分量是由源处的高频信号（超声波）产生的，这是由于介质在高声压幅度下的非线性和谐振器的配置（几何形状和边界）造成的。我们还表明它们具有幅度阈值依赖性，这与文献一致。这些次谐波对不同压力幅度序列的响应也揭示了气泡液体的滞后性质。