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Item type:Publication, Access status: without files , Resistance tests with 3D printed models in the early ship design stage of high speed vessels(2019-09); ; Resistance prediction for high speed vessels (Fn > 0.5) is a challenging task in the early ship design stage. On the one hand, model tests deliver satisfying results, which are on the other hand expensive and time consuming. Testing of different versions of the hull form using model tests in the design process is nowadays not economical. In the last years, 3D printing gained in importance in industrial applications like rapid prototyping. The enhancing quality makes the technology suitable for the production of ship models, as cost and production time can be reduced significantly. Hence, towing different versions of the hull design becomes an alternative to usual approaches. In this paper the application of 3D printed ship models is presented exemplary for a new hull design of a high speed vessel operating at a Froude number of 0.912 using the results of a bachelor thesis.Publicationtype: Conference Paper167 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Study of weakly nonlinear water waves subjected to stochastic wind excitation(2019-09); The behavior of deep-water gravity waves under the effect of wind and viscosity is studied. It is analyzed, how random wind affects the Peregrine breather, which is considered as a possible prototype of extreme waves in the oceans. Using the Euler equations of fluid dynamics and the method of multiple scales, the nonlinear Schrödinger equation and the modified nonlinear Schrödinger equation are obtained for the case of nonlinear deep water waves forced by random wind. For modeling the wind forcing of ocean waves, Miles’ theory is extended to include time varying random wind velocity processes, which leads to stochastic partial differential equations. For different regimes of stochastic wind it is shown that perturbed versions of the Peregrine solution occur also under strong gusty wind conditions and lead to extreme waves as well. Moreover, the improved modeling using the modified nonlinear Schrödinger equation does not considerably change this behavior.Publicationtype: Conference Paper193 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , On the seakeeping behaviour of an offshore wind farm vessel during the jack-up process in the early design stage(2019-06)Offshore wind farm vessels are oftentimes equipped with jack-up legs, to lift the hull above the water surface at the site of operation. The vessels’ harmonic motions in a seaway must be within defined limits during the initial contact of leg and seabed. This paper therefore presents the implementation of the legs’ hydrodynamic influence on the seakeeping behaviour in an existing seakeeping analysis method for application in the early design stage. It is based on a frequency domain, linear strip method providing response amplitude operators in a regular seaway. The legs’ hydrodynamic influence is included by a Morison approach. The presented method provides the possibility to quickly calculate the response motions of a jack-up vessel in a regular seaway during the jack-up process. It represents a fast computational tool for the early design stage to design the vessel especially for the environmental conditions of the site of operation.Publicationtype: Conference Paper135