Response of a Partially Submerged Pendulum Under Gravity Waves

In this paper, an experimental investigation is conducted to study the hydrodynamic interaction between a partially submerged pendulum. The pendulum is made by fixing a spherical ball at one end of a small diameter rigid rod, whose other end is hinged. The pendulum is hinged to the bottom of a water wave tank. Particle image velocimetry and high-speed imaging measurements are applied here to investigate the oscillation properties of the pendulum placed transversely in the waterway, which is induced due to gravity waves in a water channel. Using image analysis tools, we obtain the time series of the angle of the pendulum from the equilibrium position. Their frequency spectra reveal a subharmonic response in addition to the primary resonance. The instantaneous velocity field is also shown with the help of particle image velocimetry.