Capturing Two Consecutive Green Water Events by Convolution

2019 ◽  
Author(s):  
Jassiel V. Hernández-Fontes ◽  
Rodolfo Silva-Casarín ◽  
Edgar Mendoza
Keyword(s):  
Time Series ◽  
Green Water ◽  
Analytical Models ◽  
Regular Waves ◽  
Convolution Model ◽  
Water Elevations ◽  
Convolution Approach ◽  
Fixed Structure ◽  
Hydrodynamic Effects ◽  
Selection Of

Abstract Capturing the propagation of green water events on in ships and other marine structures is of importance when studying the hydrodynamic effects on their motion and the structure’s behavior. Analytical models used to predict green water elevations, such as dam-break models, have been considered to represent time series of water elevations of single green water events. This paper presents the use of a convolution approach to represent the time series of water elevations of two consecutive green water events on deck of a fixed structure. The procedure is described considering green water events, generated with regular waves, on a barge-type fixed structure. Its application is compared with results available elsewhere in the literature. With the assumptions related with the selection of input parameters of the convolution model, and considering only the first green water event, the results show that this methodology allows two consecutive green water events to be captured acceptably. It is hoped that this methodology will be useful in further time-domain applications which study the dynamic behavior of structures subjected to green water.

scholarly journals Green Water on A Fixed Structure Due to Incident Bores: Guidelines and Database for Model Validations Regarding Flow Evolution

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2584 ◽  
Author(s):  
Jassiel V. Hernández-Fontes ◽  
Paulo de Tarso T. Esperança ◽  
Juan F. Bárcenas Graniel ◽  
Sergio H. Sphaier ◽  
Rodolfo Silva
Keyword(s):  
High Speed ◽  
Temporal Distribution ◽  
Dam Break ◽  
Green Water ◽  
Two Dimensional ◽  
High Resolution Data ◽  
Water Elevations ◽  
Fixed Structure ◽  
Flow Propagation ◽  
Air Cavities

This paper presents a two-dimensional experimental study of the interaction of wet dam-break bores with a fixed structure, regarding the evolution of the incident flows and the resultant green water events on the deck. The study employs image-based techniques to analyse flow propagation from videos taken by high-speed cameras, considering five different shipping water cases. The features of small air-cavities formed in some green water events of the plunging-dam-break type were analysed. Then, the spatial and temporal distribution of water elevations of the incident bores and green water were investigated, providing a database to be used for model validations. Some guidelines for the selection of the freeboard exceedance, which is of relevance for green water simulations, were provided. Finally, the relationship between the incident bore and water-on-deck kinematics was discussed. The proposed study can be used as a reference for performing simplified and systematic analyses of green water in a different two-dimensional setup, giving high-resolution data that visually capture the flow patterns and allow model validations to be performed.

Influence of hydrodynamic effects on iceberg collisions

1990 ◽  
Vol 17 (3) ◽  
pp. 329-337 ◽  
Author(s):  
Michael Isaacson ◽  
Kevin McTaggart
Keyword(s):  
Added Mass ◽  
Offshore Structures ◽  
Ocean Engineering ◽  
Iceberg Drift ◽  
Added Masses ◽  
Waves And Currents ◽  
Fixed Structure ◽  
Wave Induced ◽  
Hydrodynamic Effects ◽  
Selection Of

This paper examines various hydrodynamic effects which should be considered when analyzing iceberg collisions with a fixed structure. Iceberg added mass is among the hydrodynamic parameters that must be known to evaluate collision severity. Effective added mass is shown to vary with collision duration and recommendations are made for the selection of added masses to be used in iceberg collision design. Iceberg impact velocities are influenced by waves and currents, which can both be significantly influenced by the presence of a large structure. Wave-driven iceberg drift motions are shown to be more sensitive than current-driven motions to the presence of a structure. The contribution of wave-induced oscillatory motions to impact velocity is also discussed. Key words: added mass, hydrodynamics, ice impact, icebergs, ocean engineering, offshore structures.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

Slamming and green water loads on a ship sailing in regular waves predicted by a coupled CFD–FEA approach

2021 ◽  
Vol 241 ◽  
pp. 110107
Author(s):  
Jialong Jiao ◽  
Songxing Huang ◽  
Tahsin Tezdogan ◽  
Momchil Terziev ◽  
C. Guedes Soares
Keyword(s):  
Green Water ◽  
Regular Waves

Selection of Neural Network for Crime Time Series Prediction by Virtual Leave-One-Out Tests

2019 ◽  
pp. 117-133
Author(s):  
Stanisław Jankowski ◽  
Zbigniew Szymański ◽  
Zbigniew Wawrzyniak ◽  
Paweł Cichosz ◽  
Eliza Szczechla ◽  
...  
Keyword(s):  
Neural Network ◽  
Time Series ◽  
Time Series Prediction ◽  
Virtual Leave One Out ◽  
Leave One Out ◽  
Selection Of

A Process Planning Method for Improving the Build Performance in Stereolithography

1999 ◽  
Author(s):  
Aaron P. West ◽  
David W. Rosen
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Analytical Models ◽  
Multi Objective Optimization ◽  
Process Variables ◽  
Build Time ◽  
Insight Into ◽  
Conflicting Goals ◽  
Selection Of

Abstract A process planning method is presented in this paper to aid stereolithography users in the selection of appropriate values of build process variables in order to achieve specific goals and characteristics that are desirable in the end prototype. To accomplish this, user-defined input in the form of goal preferences and feature tolerances are used to control how the prototype will be built by way of process planning. The user inputs will be used to drive the creation of the process plan so that a prototype is produced, which reflects the intent of the operator. The process planning method is adapted from multi-objective optimization and utilizes empirical data, analytical models, and heuristics to quantitatively relate build process variables to goals of surface finish, accuracy, and build time. The objective is to render decision support by handling tradeoffs among conflicting goals quantitatively and give the user some degree of insight into what quality of prototype may ultimately be produced. The process planning method is demonstrated on a part with non-trivial geometric features.

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