## 7 Conclusions  
The present work carried out a numerical study of an OWC wave energy converter, considering different numbers of coupled devices. The objective of the investigation was to evaluate the influence of the geometric variation and the number of coupled hydropneumatic chambers, keeping the volume of the device constant over the available hydropneumatic power converted by the devices. The studies carried out applied the association of computational modeling with Constructal Design and Exhaustive Search. The first is based on CFD, which approaches the mass and momentum conservation equations in differential form through a system of algebraic equations and uses the VOF methodology, which reproduces the interaction between the fluids involved in the numerical simulation. The exhaustive search method allows one to go through all the results and discover the geometric arrangement with the highest performance of each coupled chamber number into the search space defined with Constructal Design. As part of the Constructal Design method, degrees of freedom were defined as \(H_{1}\)/\(L_{1}\), \(H_{2}\)/\(L_{2}\), \(H_{3}\)/\(L_{3}\), \(H_{4}\)/\(L_{4}\), and \(H_{5}\)/\(L_{5}\). The problem restrictions in question were defined as the volume of the hydropneumatic chambers (\(V_{EI}\), \(V_{E2}\), \(V_{E3}\), \(V_{E4}\), and \(V_{E5}\)), the volume of each hydropneumatic chamber added to the turbine duct volume (\(V_{T1}\), \(V_{T2}\), \(V_{T3}\), \(V_{T4}\), and \(V_{T5}\)), and the thickness of the columns that divide the devices, which are kept constant (\(e_{1}\), \(e_{2}\), \(e_{3}\), \(e_{4}\), and \(e_{5}\)). The results for pressure, mass flow rate, and available hydropneumatic power were analyzed. All the results were presented for each of the studied geometries. The dimension variations of the hydropneumatic chambers are responsible for the increase or the decrease in pressure and mass flow rate, also associated with the oscillatory movement of the waves inside the chambers, thus creating the piston effect that varies along with the geometries. The pressure and mass flow rate have an important influence on the estimate of hydropneumatic power. This aspect can be attested by the range of geometric ratios in which the highest performance cases are the same for the three parameters. In all configurations of coupled chambers, a maximum point was verified in the power results. These results show the tendency to achieve one point of optimal performance of the length/height ratio of the hydropneumatic chamber. The results show that as the number of chambers increases, the performance indicator has higher values for the present conditions studied. Therefore, devices with five coupled chambers led to the highest magnitudes of hydropneumatic power. In all cases analyzed, the optimal values were always in the range \(0.25<Hn/Ln<0.50\). For a lower number of coupled chambers, these magnitudes of the ratio Hn/Ln were in the same range reached by other authors, e.g., [PERSON] et al. [19; 20]. The difference of the available hydropneumatic power for the optimal and worst cases, within the range of values \(Hn/Ln\) investigated, was \(85.4\%\). The geometries and powers of these cases show that \(Hn/Ln=0.2613\) (\(Hn=4.1335\) m and \(Ln=15.8219\) m), \([P_{hyd}l_{opt}=30.8\) kW and \([P_{hyd}l_{opt}=4.5\) kW for the higher and lower hydropneumatic power, respectively. Thus, it is inferred that with the analysis of the insertion of hydropneumatic chambers, keeping the input volume constant, devices with five chambers coupled have an increase in the energy conversion superior to the other cases with fewer chambers. Future work must analyze the variation in degrees of freedom involving the turbine ducts and thus determine the complete geometric configuration (hydropneumatic chamber plus turbine duct) that conducts the highest hydropneumatic power. Conceptualization, Y.T.B.d.L., L.A.O.R., E.D.d.S. and L.A.I. ; methodology, Y.T.B.d.L., and M.d.N.G. ; software, Y.T.B.d.L., and M.d.N.G. ; validation, Y.T.B.d.L.