Filters

Settings

Now showing1 - 2 of 2
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Deterministic non-linear wave forecast and motion prediction for short-term offshore operations
    (ISOPE, 2015-06)
    Clauss, Günther F.
    ;
    Klein, Marco
    ;
    Dudek, Matthias
    ;
    Onorato, Miguel
    This paper presents a time-domain decision support system based on deterministic, non-linear wave forecast and motion prediction for short-term offshore operations. The system consists of three individual constituents: sea state registrations, non-linear wave forecast and motion prediction. Surface elevation snapshots taken continuously by a ship board radar at great distance ahead the operational area are preprocessed by the wave monitoring system WaMoS II1 and used as input for the wave forecast tool. The non-linear wave propagation is modelled by applying the Higher Order Spectral Method (HOSM), which offers high accuracy and fast calculation time at once. The predicted surface elevation at the location of operation are used for the evaluation of the corresponding offshore structure response. For this purpose, Impulse Response Functions are implemented, which enable the fast determination of the response in time domain. The focus of the present study lies on the evaluation of the non-linear wave forecast and motion prediction part of the proposed decision support system. For illustrating the efficiency of the process, an offshore crane operation is investigated. The accuracy of the predicted (future) surface elevation as well as response of the multi-body problem is evaluated against model tests in the controlled environment of a seakeeping basin.
    Publicationtype: Conference Paper
      65
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Assessment of uncertainty due to wave reflections in experiments via numerical flow simulations
    (ISOPE, 2015-06)
    Peric, Robinson
    ;
    Abdel-Maksoud, Moustafa
    Reflections at the wave-maker and tank boundaries can be a dire problem in wave tank experiments. Often, such reflections cannot be avoided. The present paper proposes an approach to quantify this influence via numerical flow simulations. It is straight-forward to redo the actual experiment "virtually" in a flow simulation, featuring full reflections as present in the wave tank experiment. It is shown that reflections at the wave-maker and domain boundaries can be nearly eliminated by applying appropriate boundary conditions in combination with domain-internal wave generation approaches. This is demonstrated for the case of a boat subjected to regular deep water waves from starboard side. Flow simulations based on the Euler equations are performed for a realistic model scale setup, in a similar manner as experiments in a narrow wave tank would be performed. Subsequently, the simulation is repeated in such a way, that undesired wave reflections at both the domain boundaries and the wave-maker are minimized. From the comparison, it is possible to separately assess the influence of wave reflections at the wave-maker as well as at the wave tank boundaries.
    Publicationtype: Conference Paper
      75