Estimation of suspended sediment concentration in Guamá River in the Amazon region.

Monitoring of the suspended sediment concentration (SSC) is important for the analysis of morphological processes in watersheds and rivers, river habitats, and human activities associated with river management. Acoustic Doppler current profilers (ADCP) are used for measurements of flow and velocity in rivers through acoustic waves, which can also be converted into sediment concentrations. In this context, the objective is to verify the applicability of the use of ADCPs (Sontek YSI, model M9 River Surveyor) as an alternative for SSC estimates, this being a recent application of the equipment, mainly in rivers in the Amazon region rich in sediments in suspension. Thus, the Gartner method was used, calibrating its equation with the concentrations obtained by the point sampling method, collected with a bottle of Van Dorn in the Guamá River, Amazon, Brazil. The method used to obtain the SSC with data measured via ADCP resulted in a satisfactory estimate of the concentrations. The correlations between the measured and estimated sediment concentrations had R2 = 0.6827 for point sampling method and R2 = 0.8103 for vertically averaged SSC. These satisfactory results demonstrate the potential of using ADCP to estimate sediments suspended in Amazon basin.

Contribution to the marine propeller hydrodynamic design for small boats in the Amazon region / Contribuição ao projeto hidrodinâmico de propulsores marítimos voltados as pequenas embarcações da região Amazônica

In the Amazon, river navigation is very important due to the length of navigable rivers and the lack of alternative road networks. Boats usually operate in unfavorable conditions, since there is no hydrodynamic relation among propellers, geometry, and the dimensions of the boat hull. Currently, there is no methodology for propeller hydrodynamic optimization with low computational cost and easy implementation in the region. The aim of this work was to develop a mathematical approach for marine propeller design applied to boats typically found on Amazon rivers. We developed an optimized formulation for the chord and pitch angle distributions, taking into account the classical model of Glauert. A theoretical analysis for the thrust and torque relationships on an annular control volume was performed. The mathematical model used was based on the Blade Element Momentum Theory (BEMT). We concluded that the new methodology proposed in this work demonstrates a good physical behavior when compared with the theory of Glauert and the experimental data of the Wageningen B3-50 propeller.

Na Amazônia, a navegação é muito importante devido a extensão de rios navegáveis e a falta de redes rodoviárias alternativas. As embarcações geralmente trabalham em condições desfavoráveis, uma vez que não há relação entre a hidrodinâmica dos hélices, geometria e as dimensões do casco da embarcação. Atualmente, não há metodologia para otimização hidrodinâmica com baixo custo computacional e fácil implementação na região. O objetivo deste trabalho foi o desenvolvimento de uma abordagem matemática voltada para o projeto de propulsores marítimos aplicados as embarcações tipicamente encontradas nos rios da Amazônia. Nós desenvolvemos uma formulação otimizada para o cálculo das distribuições de corda e ângulo de torção, considerando o modelo clássico de Glauert. Uma análise teórica para as relações de empuxo e torque em um volume de controle anular foi realizado. O modelo matemático utilizado foi baseado na teoria do momento do elemento de pá (BEMT). Concluímos que a nova metodologia, proposta neste trabalho, demonstra bom comportamento físico quando comparado com a teoria de Glauert e os dados experimentais do propulsor Wageningen B3-50.