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Overpelt B.,Maritime Research Institute Netherlands
RINA, Royal Institution of Naval Architects - Warship 2014: Naval Submarines and UUV's, Papers | Year: 2014

One of the major issues in operating diesel-electric powered (SSK) submarines at the surface is the high wave making resistance, leading to a fairly low transit speed compared to commercial ships navigating the same waters, relatively high fuel costs and large-sized hull forms due to the required bunker capacity in order to have reasonable range. Therefore, the Dutch Defence Materiel Organisation (DMO) and the Maritime Research Institute Netherlands (MARIN) have performed a study on the submerged and surfaced performance of a typical 4000t SSK submarine with three different bow shapes. This paper describes the design and evaluation of the alternative bow shapes and shows how this can be used to evaluate which bow shape fits best in various operational profiles. © 2014 The Royal Institution of Naval Architects. Source

Eca L.,University of Lisbon | Hoekstra M.,Maritime Research Institute Netherlands
Computers and Fluids | Year: 2011

This paper presents a study on the numerical requirements of including sand-grain wall roughness effects in the SST k-ω eddy-viscosity model. Three implementations are tried: two retain the direct application of the no-slip condition at the wall, the third is based on a wall function formulation. In the first two options the roughness effect is introduced via a change in wall boundary conditions, either for ω only or for k and ω. The two-dimensional flow along a finite flat plate is adopted to assess the numerical accuracy of the three approaches. The computed results are also compared with semi-empirical formula available in the open literature. It is demonstrated that sand-grain roughness effects can be simulated with acceptable numerical uncertainties with all three options, but the numerical settings to achieve that goal differ significantly. © 2010 Elsevier Ltd. Source

Bons A.,Maritime Research Institute Netherlands
RINA, Royal Institution of Naval Architects - International Conference on Computer Applications in Shipbuilding 2013, ICCAS 2013 | Year: 2013

This paper discusses the method CoPAr, which allows combining predefined arrangements into new ship designs. Its development is a result of a combined effort of the Netherlands' Defence Materiel Organisation and the Maritime Research Institute Netherlands. The method is built around the existing Integrated Functional Naval Ship Design Tool. This flexible design model finds application in concept development and parameterises each design solution to its dedicated set of parameters. Consequently, it is necessary to split the design data from the parameterisation data. In order to allow the design model to meaningfully interpret the design data of a combined arrangement, the method needs to reattach it to the parameterisation specified by the user. CoPAr has been successfully applied in a combatant design study, in which beneficial design features of two existing designs were combined into a third, new design. This application demonstrates practical use and workload reduction of the developed method. © 2013: The Royal Institution of Naval Architects. Source

Mou J.M.,Wuhan University of Technology | Tak C.v.d.,Maritime Research Institute Netherlands | Ligteringen H.,Technical University of Delft
Ocean Engineering | Year: 2010

Due to high density of vessel traffic, busy waterways are water areas with high potential for collisions. The application of AIS makes it possible to investigate accurate and actual behavior of collision-involved ships, and benefits vessel traffic management and waterways design for these areas. As a case study, the authors focus on a Traffic Separation Scheme (TSS) off Rotterdam Port in Europe, and using AIS data, statistical analysis is made for collision involved ships. In order to identify the correlation of CPA, which is a key indicator for collision avoidance, with ship's size, speed, and course, linear regression models are developed. To assess risks, a dynamic method based on SAMSON is presented. © 2010 Elsevier Ltd. All rights reserved. Source

Make M.,Maritime Research Institute Netherlands Academy | Vaz G.,Maritime Research Institute Netherlands
Renewable Energy | Year: 2015

In this paper the flow over two (floating) wind turbines has been studied using RANS CFD calculations at model and full-scale Reynolds numbers conditions. The well-known NREL 5MW and MARIN designed turbines (MARIN Stock Wind Turbine or MSWT) have been analysed. The MSWT was designed to have the same thrust at model-scale as the NREL turbine at full-scale conditions. The thrust was the major driver since it is more important for the behaviour of the floating platform. Numerical sensitivity studies were done to minimize all possible uncertainties: domain size, iterative convergence, grid refinement, and turbulence model sensitivity was studied. Modern verification and validation procedures were used to assess those uncertainties and to perform a validation of the numerical results against experimental data coming from constant uniform inflow, fixed turbine experiments. Furthermore, the flow around the turbines and its performance, both for model and full-scale, have been scrutinised, compared, and insights into their behaviour and Reynolds/scale effects gained. A good agreement between the CFD results and the experimental data has been obtained, with low uncertainties for thrust but large uncertainties for power. The large Reynolds effects on the flow of these turbines have been also shown and explained. Finally, it has been confirmed that the MSWT performs as intended at model-scale conditions. © 2015 Elsevier Ltd. Source

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