Comparison of the performance of oscillating water column devices based on arrangements of water columns

Abstract

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

Review of the Influence of Oceanographic and Geometric Parameters on Oscillating Water Columns

“…Tseng et al (2000) reported that multi-resonant OWCs yield only 28.5% efficiency due to high energy losses [80]. Atan et al (2019) studied the effect of arrays of OWCs on the nearshore wave climate and concluded that they do not significantly alter the nearshore climate [81], and finally, Jasron et al (2020) studied three different arrangements of OWC devices to optimize their performance [82]: a single water column, a double water column in series arrangement perpendicular to the direction of wave propagation, and a double water column parallel to the direction of wave propagation. The results showed that the double OWC configuration operates more efficiently at deeper water depths than the single device and that the efficient frequency bandwidth is broader, especially for an arrangement in which the OWCs are in parallel, which showed a more stable behavior.…”