CFD-BASED SIMULATION OF THE FLOW AROUND A SHIP IN OBLIQUE MOTION AT LOW SPEED

Ships tend to maneuver in oblique motion at low speed in situations such as turning in a harbor, or during offloading, dynamic positioning and mooring processes. The maneuverability criteria proposed by IMO are valid for ships sailing with relatively high speeds and small drift angles, which are inadequate to predict ship maneuverability in low speed condition. Hydrodynamic performance of ships maneuvering at low speed is needed to know for safety issues. A CFD-based method is employed to predict the flow around an Esso Osaka bare hull model in oblique motion at low speed, where the drift angle varies from 0° to 180°. The URANS method with the SST k-ω model is used for simulating ship flows with drift angles 0°~30° and 150°~180°, and DES method for simulating ship flows with drift angles 40°~150°. Verification and validation studies are conducted for drift angles of 0° and 70°. The vortex structures at typical drift angles of 0°, 30°, 50°, 70°, 90° and 180° are analyzed. The effects of drift angle and ship speed are demonstrated.

Promoting Korean international trade in the East Sea Economic Rim in the context of the Belt and Road Initiative

Purpose The purpose of this paper is to analyze maritime logistics connectivity of ports and shipping networks in the East Sea Economic Rim (ESER) to promote international trade in the context of China’s Belt and Road Initiative (BRI), considering centrality, primary flow and clustering interaction. Design/methodology/approach The paper applies a complex network model, using a big data system consisting of an automated identification system, electronic data interchange and distributive and complex data. Three perspectives, including connectivity in trading ports and regions, centralities in the realm of complex network and potential marketing and regional impacts, and sixteen criteria are considered for this analysis. A visual approach has been also applied to highlight port connectivity and ship flows for the reader’s convenience. Findings The paper shows that port connectivity and maritime logistics are enablers to promote Korean international trade in Northeast China through the ESER, and 25 major ports are well connected to promote international trade in the region with visual data of ship flows by ship type and by flag. Research limitations/implications Owing to the lack of port management information systems among the countries in the ESER except Korea and Japan, this paper could not capture cargo types and amounts on board. Port connectivity analysis shows links of the ports in the ESER to major ports in southeast Asia along the Twenty-first Century Maritime Silk Road (MSR). These results contribute to drawing policy implications to promote the ESER and provide suggestions for promoting Korean international trade by enhancing maritime logistics connectivity. Originality/value Unlike the existing literature showing descriptive and policy-oriented research related to ESER, this paper applied a vigorous method with a big amount of data to analyze port connectivity and ship flows in the ESER, considering China’s BRI affecting the global supply chain system, maritime transportation, and logistics. In addition, the paper shows how the seaports in the ESER are connected along the MSR.

Benchmarking of Computational Fluid Dynamics for Ship Flows: The Gothenburg 2000 Workshop

The Gothenburg 2000 was an international benchmark workshop for computational fluid dynamics applied to ship flows. Test cases were three modern hull forms. One case without a free surface focused on turbulence modeling, whereas wave prediction was of interest for the other two. Of the free-surface cases, one had an operating propeller. For the first time, verification and validation procedures were an integral part of such benchmark efforts in ship flows. The workshop showed that free-surface waves may now be well predicted also away from the hull. There is a general improvement in the computation of the stern flow thanks to better turbulence modeling, but there is still room for improvement. Full-scale viscous flows may be computed without numerical difficulties. Verification and validation procedures should be applied for uncertainty analysis, and there is a discussion of the uncertainty in the predicted integral quantities in the paper. Further detailed conclusions and recommendations are also given based on the comparison of extensive standardized plots of the comparative computations and evaluation of the integral quantities.