A Proposed Method for Determining Propulsion Coefficient Based on Testing Motor Freighters on Danube Waterway Network
R. Rajković, D. Mitić, A. Lebl, S. Rajković (DOI: 10.24874/jsscm.2019.13.01.09)
The paper presents a proposal of mathematical models for the determination of propulsion coefficient, ηpp, intended for the analysis of motor freighters applied on the river watercourses. As the main paper contribution three different model types are developed, depending on the variable which contributes to ηpp value. These variables are: 1. the freighter sailing velocity, (v); 2. the installed capacity of the main drive motor of outboard unit, (Ninst); 3. the combination of these two variables, (Ninst,v). The models are verified on the examples of several motor freighters which are applied at Danube river. The special attention is paid to the determination of the optimum approximation function in each case. In all three cases it is a quadratic function. The correlation coefficient for the comparison in all analyzed examples is higher than 0.87, being even higher than 0.99 for the first model.