###### Abstract
[18] developed numerical research considering an OWC device with a rectangular hydropneumatic chamber subject to different wave periods in full scale and varying two degrees of freedom: \(H_{1}\)/L (ratio of height to length of the hydropneumatic chamber) and \(H_{3}\) (OWC submergence). The results indicated that when the \(H_{1}\)/L ratio was four times higher than the ratio of height to length of the incident wave (\(H\)/\(\lambda\)), it maximizes the hydropneumatic power. Afterward, [PERSON] et al. [19] studied an OWC device with four coupled chambers with degrees of freedom given by \(H_{n}\)/\(L_{n}\) (ratio of height to length of the hydropneumatic coupled chambers). The results showed a hydropneumatic power peak for the mean values of the studied degrees of freedom. [PERSON] et al. [20] studied OWC devices with two coupled chambers when varying three degrees of freedom, the ratio between the height and length of the hydropneumatic chamber (\(H_{n}\)/\(L_{n}\)), and the height (\(H_{2}\)) and thickness (\(e_{2}\)) of the wall that divides the coupled chambers. As a result, the authors found a power of 5.7 kW when the height/length ratio of the hydropneumatic chambers is 0.2613 and height and thickness of the wall that divides the coupled chambers are 4.13 m and 0.13 m, respectively. In [PERSON] et al. [21], a full-scale onshore OWC device with three degrees of freedom was considered: the ratio between the height and length of the hydropneumatic chamber, the ratio between height and length of the ramp of the device, and the depth of submersion of the device. The results showed that using the seabed ramp led the power to a maximum conversion of 37.3% compared to the best case without the ramp. Unlike the previous results in [PERSON] et al. (2021), a JONSWAP wave spectrum was used to study the influence of different geometries for the hydropneumatic chamber with one degree of freedom: \(H_{1}\)/\(L\) (ratio between the height and length of the OWC chamber entrance). A wave spectrum is a classification referring to irregular waves that can be decomposed by harmonic analysis (Fourier) into a large number of regular waves of different frequencies, directions, amplitudes, and phases. The JONSWAP spectrum is an extension of another spectrum, the Pierson-Moskowitz spectrum, being differentiated by the fact that it considers that waves continue to grow with distances (or time) and the wave peak in this spectrum is more pronounced because it leads to enhanced non-linear interactions and one spectrum that changes in time ([PERSON], 2019; [PERSON], 2019). Thus, four distinct chamber geometries were analyzed: rectangular, trapezoidal, inverted trapezoid, and double trapezoid. The results indicated that the rectangular geometry reached an improvement superior to the others studied. In this context, the present numerical work aims to perform a geometric evaluation of an offshore OWC device with different hydropneumatic chambers coupled in full scale. The format of the chambers is varied through Constructal Design ([PERSON], 2019), changing the degrees of freedom \(H_{n}\)/\(L_{n}\) (the ratio between height to length of the hydropneumatic coupled chambers), where \(n\) varies according to the number of coupled chambers. In addition, the performance indicator assesses the available power to be maximized using the analysis of the geometries. It is noteworthy that the computational model did not consider a turbine in the duct that allows air flow. It is worth mentioning that it is simulated here only the main operating principle of the OWC device. Then, it is considered an incompressible, transient, and two-dimensional water-air multiphase flow. Conservation equations of mass and momentum and one equation for the transport of the water volume fraction are numerically solved with the FVM ([PERSON], 2019; [PERSON], 2019). The multiphase VOF model is used ([PERSON], 2019; [PERSON], 2019) to tackle the water-air interface.