Search Results (4)

Experimental testing of physical turbines, often at a smaller scale, is an essential tool for engineers to investigate fundamental design parameters such as power output and efficiency. Despite issues with scaling and blockage which are caused by limitations in size and flow velocity of the test facilities, experimental tank testing in laboratory environments is often perceived as offering more control and thus trustworthier results than field testing. This paper presents field tests of a tidal turbine, performed using a self-propelled barge in real tidal flow and still water conditions, that are compared to a towing tank test. Factors influencing the performance characteristics, such as the choice of velocity sensor, vessel handling and data processing techniques are investigated in this paper. Direct comparison with test results of the exact same turbine obtained in an experimental test facility further confirms that field testing with robust data analysis capabilities is a viable, time and cost efficient alternative to characterise tidal turbines. Full article

In Ukraine, there has been an increase in agricultural production. The availability of river basins and seaports contributes to the use of inland shipping. However, there is a lack of understanding of how to reduce the energy consumption of inland shipping. We assume the hypothesis that the energy efficiency of inland shipping is much higher than it is technically possible. The purpose of this study is to identify perspective energy-saving technologies for IWT. We use statistical information to determine the export potential and to reveal the status of inland navigation. Traction efficiency, theoretical and actual specific fuel consumption were used as indicators to determine the energy efficiency. The main results are as follows. We have found the grain and sunflower seed production in the Dnieper Basin (Ukraine). Their shares range from 34.75 to 50.92% of national production. Therefore, there is a significant flow of products for inland shipping. The present status of inland waterways transport has been analyzed. The main novelty of this study is the finding of actual and theoretical technical specific energy consumption. It is revealed that actual specific energy consumption is five times higher compared to the theoretical one. Self-propelled vessels are inferior in energy efficiency to towing barges. The energy efficiency of inland waterways transport has been compared to railways and road freight transport. Transport management was identified as the more effective tool to improve the energy efficiency of inland shipping. Full article

Expanding the automation level of the freshly introduced fleet of self-propelled Watertruck${}^{+}$ barges, which house fully-rotatable embedded thrusters, might increase their ability to compete with their less sustainable but dominating road-based alternatives. Hydrodynamic motion models, which reveal the manoeuvring capabilities of these barges, can serve as inputs for many pieces of this automation puzzle. No identified motion models or hydrodynamic data seem to be publicly available for the hull design and the novel actuation system configuration of these barges. Therefore, this study offers: (i) decoupled motion model structures for these barges for surge, sway, and yaw, with a focus on the thruster and damping models; (ii) two identification procedures to determine these motion models; (iii) all the experimental data, generated outdoors with a scale model barge to identify (i) based on (ii). In addition, the identified surge models were compared with both computational and empirical data. These comparisons offer more physical insights into the identified model structures and can aid in the model selection for which the desired complexity and accuracy evidently depend on their envisaged application. Finally, this methodology need not be limited to the vessel and actuation types utilised by us. Full article

The European ${\mathrm{Watertruck}}^{+}$ project introduced a new fleet of self-propelled inland cargo barges to the European waters, in order to induce more sustainable freight transport in the European hinterland. An augmentation of the automation level of this fleet could further advance their competitiveness and potentially pave the way for unmanned inland cargo vessels. The motion control of such a vessel forms a key component in this envisaged automation chain and benefits from the knowledge of the capabilities of the propulsion system, which here envelops a 360-degrees-steerable steering-grid thruster in conjunction with a 360-degrees-steerable four-channel thruster. Therefore, this study details the mechanical design of both thrusters and lists their experimental towing-tank data. Furthermore, two different modelling methods are offered, one theoretically based and one using a multilayer neural network. A model structure comparison, based on a bias-variance trade-off, verifies the adequacy of the theoretical model which got expended with an angle-dependent thrust deduction coefficient. In addition, several multilayer feedforward neural network architectures exemplify their inherent capability to model the complex, nonlinear, flow phenomena inside the thrusters. These identified model structures can additionally improve thrust allocation algorithms and offer better plant models to study more advanced control strategies. Full article