Computational fluid dynamics (CFD) prediction of bank effects including verification and validation

Restricted waters impose significant effects on ship navigation. In particular, with the presence of a side bank in the vicinity of the hull, the flow is greatly complicated. Additional hydrodynamic forces and moments act on the hull, thus changing the ship's maneuverability. In this paper, computational fluid dynamics methods are utilized for investigating the bank effects on a tanker hull. The tanker moves straight ahead at a low speed in two canals, characterized by surface piercing and sloping banks. For varying water depth and ship-to-bank distance, the sinkage and trim, as well as the viscous hydrodynamic forces on the hull, are predicted by a steady state Reynolds averaged Navier–Stokes solver with the double model approximation to simulate the flat free surface. A potential flow method is also applied to evaluate the effect of waves and viscosity on the solutions. The focus is placed on verification and validation based on a grid convergence study and comparisons with experimental data. There is also an exploration of the modeling errors in the numerical method.     

政府支持下的瑞典铁路实施网运分离

阐述了瑞典铁路在重组过程中政府的支持力度，以及政府支持下运输政策的变化、BV所发挥的作用和重组的最新进展，分析了网运分离的优势。     

The effects of an acceleration advisory tool in vehicles for reduced fuel consumption and emissions

This study evaluates whether the use of an acceleration advisor leads to fuel savings, to determine the change in traffic-related emissions and to analyse changes in driving patterns on various routes. The acceleration advisor provides advice to drivers through resistance in the accelerator pedal when they try to accelerate rapidly. In a test carried out in Southern Sweden, the acceleration advisor was installed in four postal delivery vehicles. The driving pattern parameters show that strong acceleration was significantly reduced, which indicated that the drivers had complied with the advisor. On two of the three routes, the acceleration advisor had a positive effect on emissions. In general, no significant reduction in fuel consumption was observed when driving with the acceleration advisor activated.     

Hazardous material incidents: Some key results of a risk analysis

Human safety and health, environmental and property protection and security concerning hazardous materials supply chain are important issues for many countries, industries and organisations around the world. This paper presents some key results of a comprehensive risk study on hazardous materials supply chain incidents. Based on a risk analysis framework adapted for maritime transport of packaged dangerous goods, this study combines qualitative and quantitative analysis of large and diverse datasets collected from some of the U.S.’s best and largest data sources. The study may be one of the largest of its kind, and some of the results might not be found elsewhere. Incidents have occurred in every system of the hazardous materials supply chain, including platforms, all modes of transport, chemical plants, terminals and storages. The results show that more than half (52.1 %) of incidents are attributed to the transport system. The study largely considers incidents happening during maritime transport, which account for 18% of transport incidents. In absolute terms, the FN curves of maritime transport human risks are generally found to be well below the corresponding FN curves of aggregated supply chain human risks.     

An experimental/numerical approach for evaluating skin friction on full-scale ships with surface roughness

For an accurate evaluation of the increase in skin friction due to various surface topographies on ships, i.e. plate roughness, coatings, or bio fouling, both experimental measurements and a numerical evaluation of those measurements are necessary. The measurements are necessary as no other practical method exists to evaluate the skin friction coefficient on most surface topographies, and numerical evaluation is required to compute the roughness effects of varying ship types and speeds. Therefore, a method for measuring the skin friction coefficient for bio-fouled and structured surfaces at full-scale friction velocity is presented, and a validation of the design and measuring procedures is given. For the ship frictional resistance calculations, the Computational Fluid Dynamics (CFD) code ShipFlow has been modified to take the added friction into account.