Experimental Observation of Negative Effective Gravity in Water Waves

TitleExperimental Observation of Negative Effective Gravity in Water Waves
Publication TypeJournal Article
Year of Publication2013
AuthorsHu XH, Yang J, Zi J, Chan CT, Ho KM
Journal TitleScientific Reports
Volume3
Pages1916
Date Published05
Type of ArticleArticle
ISBN Number2045-2322
Accession NumberWOS:000319553800003
KeywordsARRAY, metamaterials, power, propagation, refractive-index
Abstract

The gravity of Earth is responsible for the formation of water waves and usually difficult to change. Although negative effective gravity was recently predicted theoretically in water waves, it has not yet been observed in experiments and remains a mathematical curiosity which is difficult to understand. Here we experimentally demonstrate that close to the resonant frequency of purposely-designed resonating units, negative effective gravity can occur for water waves passing through an array of resonators composing of bottom-mounted split tubes, resulting in the prohibition of water wave propagation. It is found that when negative gravity occurs, the averaged displacement of water surface in a unit cell of the array has a phase difference of pi to that along the boundary of the unit cell, consistent with theoretical predictions. Our results provide a mechanism to block water waves and may find applications in wave energy conversion and coastal protection.

URL<Go to ISI>://WOS:000319553800003
DOI10.1038/srep01916