Author(s): Maciej Paprota
Linked Author(s):
Keywords: Pneumatic breakwater; Wave transmission; PIV measurements; Wave flume
Abstract: Transmission of waves through a submerged aerial barrier is studied experimentally in a wave flume. The aim of the study is to evaluate effectiveness of aerial barriers used as breakwaters and identify processes responsible for wave energy dissipation. The experiments are conducted in a wave flume for different wave and aerial barrier parameters including air flow rate and number of pipes used to generate pneumatic curtains. The model of the pneumatic breakwater is constructed and placed in the wave flume. Perforated pipes are installed on the wave flume bottom and are connected to a piston-type air compressor that provides a desired amount of air for experiments. The continuous aerial barrier is formed across the wave flume width. Regular waves of fixed parameters are generated by the wavemaker. The waves are propagating through the aerial barrier. The parameters of the aerial barrier are modified by changing the number of perforated pipes and the amount of air supplied by the air compressor. Velocity fields of air and water mixture are measured in direct vicinity of the pneumatic breakwater by employing PIV technique. The 2D Flow Master system is used. It measures flow velocity in a plane using camera and laser. The plane is parallel to the side walls of the wave flume and perpendicular to the aerial barrier. The resulting velocity fields provide information on two vector components in a cross section of the aerial barrier. The free-surface oscillations of water are registered in front of and behind the pneumatic breakwater by resistant-type wave gauges in order to estimate transmission coefficients. Based on the measurements the effectiveness of the pneumatic breakwater in different wave conditions is analysed. The current structure of the area of action of the pneumatic breakwater is analysed.
Year: 2014