Focusing of liquid surface waves by gradient index lens
College of Civil Engineering and Architecture, Zhejiang University - Hangzhou 310058, PRC
Received: 16 August 2014
Accepted: 1 October 2014
In the long-wavelength limit, a periodic array of bottom-mounted vertical cylinders may be used as a homogeneous medium for liquid surface waves and their effective parameters, such as their refractive index, depending on the filling fraction of the cylinders. Based on this effective medium theory, a gradient index (GRIN) lens for the focusing of liquid surface waves has been designed and fabricated here through the gradual modification of the cylinder filling fraction along a direction perpendicular to the lens axis. Their focusing performance and the transmission properties for liquid surface waves are then studied both experimentally and numerically. Both the wave patterns and spatial intensities obtained by experiment and numerical calculation demonstrate that the GRIN lens is able to focus planar liquid surface waves within a certain frequency region.
PACS: 47.35.-i – Hydrodynamic waves / 47.90.+a – Other topics in fluid dynamics (restricted to new topics in section 47) / 92.05.Jn – Ocean energy extraction
© EPLA, 2014