svingende vannsøyle_ill_endre

A fluctuating water column is enclosed in a partly-submerged hollow structure. The column is open below the water line and contains a pocket of air in its upper part. The water column rises and falls within the structure in response to wave movements. These movements cause pressure fluctuations which force air in and out of the surge chamber at the top of the structure. (Source: Illustration: Endre Bardal.