Elastic waves propagating at the interface of soft solids can be altered by the presence of external forces such as capillarity and gravity. We measure the dispersion relation of waves at the free surface of agarose gels with great accuracy, revealing the existence of multiple modes as well as an apparent dispersion. We disentangle the role of capillarity and elasticity by considering the three-dimensional nature of mechanical waves, achieving quantitative agreement between theoretical predictions and experiments. Notably, our results show that capillarity plays an important role for wave numbers smaller than expected from balancing elastic and capillary forces. We further confirm the efficiency of our approach by including the effect of gravity in our predictions and quantitatively comparing it to experiments.

中文翻译：

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毛细管作用如何影响弹性凝胶中弹性波的传播

在软固体界面传播的弹性波可以通过存在外力（例如毛细作用和重力）来改变。我们以很高的精度测量了波在琼脂糖凝胶自由表面上的色散关系，揭示了多种模式的存在以及表观色散。我们通过考虑机械波的三维性质，在理论预测和实验之间达成定量协议，来解开毛细作用和弹性的作用。值得注意的是，我们的结果表明，毛细作用在波数小于平衡弹性和毛细作用力所预期的波数中起着重要作用。通过将重力影响纳入我们的预测并将其与实验进行定量比较，我们进一步证实了该方法的有效性。