scholarly journals A simplified fluid structure interaction model for the assessment of ship hard grounding

2021 ◽  
Author(s):  
Sang Jin Kim ◽  
Jung Min Sohn ◽  
Pentti Kujala ◽  
Spyros Hirdaris
Keyword(s):  
Structural Damage ◽  
Rapid Assessment ◽  
Interaction Model ◽  
Fluid Structure Interactions ◽  
Hydrodynamic Properties ◽  
Surrounding Water ◽  
Fluid Structure ◽  
Source Codes ◽  
Added Masses ◽  
Restoring Forces

AbstractThe structural damage of ships in navigational accidents is influenced by the hydrodynamic properties of surrounding water. Fluid structure interactions (FSI) in way of grounding contact can be idealized by combining commercial FEA tools and specialized hydrodynamic solvers. Despite the efficacy of these simulations, the source codes idealizing FSI are not openly available, computationally expensive and subject to limitations in terms of physical assumptions. This paper presents a unified FSI model for the assessment of ship crashworthiness following ship hard grounding. The method uses spring elements for the idealization of hydrostatic restoring forces in 3 DoF (heave, pitch, roll) and distributes the added masses in 6 DoF on the nodal points in way of contact. Comparison of results against the method of Kim et al. (2021) for the case of a barge and a Ro–Ro passenger ship demonstrate excellent idealization of ship dynamics. It is concluded that the method could be useful for rapid assessment of ship grounding scenarios and associated regulatory developments.

scholarly journals Fish larvae tackle the complex fluid-structure interactions of undulatory swimming with simple actuation

2019 ◽  
Author(s):  
Cees J. Voesenek ◽  
Gen Li ◽  
Florian T. Muijres ◽  
Johan L. van Leeuwen
Keyword(s):  
Muscle Activation ◽  
Fish Larvae ◽  
Bending Moment ◽  
Neuromuscular Control ◽  
Numerical Approach ◽  
3D Analysis ◽  
Fluid Structure Interactions ◽  
Surrounding Water ◽  
Fluid Structure ◽  
Muscle Activation Patterns

AbstractMost fish swim with body undulations that result from fluid-structure interactions between the fish’s internal tissues and the surrounding water. As just-hatched larvae can swim effectively without a fully-developed brain, we hypothesise that fish larvae tackle the underlying complex physics with simple actuation patterns. To address this hypothesis, we developed a dedicated experimental-numerical approach to calculate the lateral bending moment distributions, which represent the system’s net actuation. The bending moment varies over time and along the fish’s central axis due to muscle actions, passive tissues, inertia, and fluid dynamics. Our 3D analysis of a large dataset of swimming events of larvae from 3 to 12 days after fertilisation shows that these bending moment patterns are not only relatively simple but also strikingly similar throughout early development, and from fast starts to periodic swimming. This suggests also similar muscle activation patterns, allowing fish larvae to produce swimming movements relatively simply, yet effectively, while restructuring their neuromuscular control system.

A Numerical Investigation Into the Value of Added Mass Coefficient for Circular Cylinders

2005 ◽  
Author(s):  
H. Karadeniz
Keyword(s):  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Offshore Structures ◽  
Circular Cylinders ◽  
Element Formulation ◽  
Fluid Structure Interactions ◽  
Shells Of Revolution ◽  
Fluid Structure ◽  
Mass Coefficient ◽  
Added Masses

This paper presents a general axi-symmetrical solid element to be used mainly for the calculation of added masses of water surrounding members of offshore structures, and in general, for multi-purposes such as analyses of shells of revolution, circular beams and plates, axi-symmetrical structures and soils, plane stress/strain problems. Since one element type is used for modeling of different media such as structures, soil and water, the element is very suitable to solve interaction problems. The element is derived parametrically so that changing values of parameters can generate flexible geometrical shapes in exact forms. In the element formulation, a constant shear locking is used to solve bending problems of beam like structures. A similar fluid element is also formulated to analyze fluid-structure interactions and to determine added masses of co-vibrating water. The added mass is calculated from hydrodynamic pressures, which are produced by fluid-structure interactions. In the paper, a special solution algorithm is presented for the coupled eigenvalue problem of the interaction. An analytic calculation of the added mass is also presented for members along which a constant variation of hydrodynamic pressure occurs. A couple of examples are provided to demonstrate applications of the elements explained. Added mass coefficients of offshore structural members (tubular members) are investigated for practical uses.

Fluid-Structure Interactions

2009 ◽  
Author(s):  
Michael Paidoussis ◽  
Stuart Price ◽  
Emmanuel de Langre
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure

Experimental Mixing Parameterization Due to Multiphase Fluid � Structure Interactions

2010 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Ranis N. Ibragimov ◽  
◽  
Akshin S. Bakhtiyarov ◽  
Margaret Snell ◽  
◽  
...  
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Multiphase Fluid

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

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