Session 9D: Wind & Naval Engineering

Title: The DLR RailwayDynamics Library: the Crosswind Stability Problem
Authors: Andreas Heckmann and Gustav Grether
Abstract:High crosswinds affect the stability of railway vehicles, in particular if they run on very high speed to reduce traveling time, if they are configured as double-deck cars to increase the number of passenger seats and if they use light-weight design in order to reduce life-cycle costs. This is why crosswind stability is an active field of research within the project Next Generation Train. However, this field relies on the cooperation of two different domains, namely aerodynamics and vehicle dynamics. With this background a crosswind stability tool was implemented in Modelica as a part of the DLR RailwayDynamics Library. This tool gathers data from scaled wind tunnel measurements and multibody data on the railway vehicle in order to rapidly analyze and assess the risk of overturning due to high crosswinds. To a large extent the tool is oriented towards the associated homologation rules and standards. However, the tool is as well supposed to support future advancements of these standards by providing capabilities for the stochastic analysis of the crosswind stability problem.
Links: Full paper

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Title: The OneWind Modelica Library for Floating Offshore Wind Turbine Simulations with Flexible Structures
Authors: Mareike Leimeister and Philipp Thomas
Abstract:Floating offshore wind turbines are getting more and more into the focus of interest, as industries aim for larger turbines and deeper water areas. Fully coupled analyses of those highly complex systems are challenging. In this paper, the hierarchical programming structure in Modelica is used to model a fully flexible floating wind turbine system. The single components, as well as special difficulties that have to be dealt with during modeling are addressed. On basis of a reference floating offshore wind turbine, the implemented fully flexible model is compared with its rigid equivalent, as well as results from code-to-code comparisons of free-decay simulations. In addition, further applications of the created model are shown.
Links: Full paper

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Title: Modelica Based Naval Architecture Library for Small Autonomous Boat Design
Authors: Thom Trentelman, Joshua Sutherland, Kazuya Oizumi and Kazuhiro Aoyama
Abstract:This paper describes a method for early stage boat design by creating and utilizing a library of naval architecture based boat components in Modelica. The method involves the construction of stand-alone boat components which can be assembled into a simulation model. Structuring the model into multiple system levels provides a clear overview. Utilizing the partial-complete methodology ensures that all system levels are replaceable within the simulation. This allows the user to construct many different boat models and experiment with unconventional or innovative designs. By comparing the performance and behaviour of different assemblies of components the most ideal design for a given purpose can be found and used as a starting point for the in-depth design process. By organizing the components in a library they can be re-used in future projects as well. It is noted that when additional libraries are utilized the effectiveness of this design method increases significantly. As the availability of component models increases, users can save time on the physical design and modelling of the individual components and instead focus on assembling working simulation models right from the beginning. To illustrate this, the construction of a few simple boat components is described in this paper. These components are then combined to simulate multiple concept designs.
Links: Full paper