On the Challenges of Agricultural Transportation in the Brazilian Amazon: A CFD Study of the Effects of Water Depth on Cargo Vessel Hydrodynamics

Inland navigation is crucial for agricultural transport in the Brazilian Amazon; however, computational fluid dynamics (CFD) methodologies are needed to evaluate the effects of seasonal water-depth changes on regional vessel performance. This paper presents a CFD study of the effects of water-depth variation on the hydrodynamics and effective power of an agricultural cargo vessel. A multiphase CFD approach was applied and validated against benchmark data for ultra-shallow-water conditions. A simplified geometry of a single pusher–barge convoy in the 1:1 configuration was considered. The effects of five water depths and three vessel speeds on the CFD results were investigated. These results show that in shallower waters, blockage effects, gap flow changes, and flow velocity variation play a relevant role in vessel hydrodynamics. A reduction in water depth is one of the determinants of changes in wall shear stress, flow velocity and hydrodynamic pressure exerted on the hull. Moreover, results demonstrated that reducing the water-depth-to-draft ratio from H/T= 6.0 to H/T = 1.2 increased total resistance and, consequently, effective power demand by approximately 16% and 14% for the lower and higher speeds evaluated, respectively. Limitations and considerations for the application of the proposed approach to investigate other agricultural cargo vessels are discussed. Existing benchmark data for ultra-shallow waters can be crucial for validating numerical approaches such as the one presented in this work, expanding the possibilities of innovation.