scholarly journals On the Use of a Domain Decomposition Strategy in Obtaining Response Statistics in Non-Gaussian Seas

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 28
Author(s):  
Griet Decorte ◽  
Alessandro Toffoli ◽  
Geert Lombaert ◽  
Jaak Monbaliu
Keyword(s):  
Domain Decomposition ◽  
Wave Interaction ◽  
Wave Structure ◽  
Offshore Structures ◽  
Short Term ◽  
Cfd Models ◽  
Highly Nonlinear ◽  
Non Gaussian ◽  
The Impact ◽  
Interaction Phenomena

During recent years, thorough experimental and numerical investigations have led to an improved understanding of dynamic phenomena affecting the fatigue life and survivability of offshore structures, e.g., ringing and springing and extreme wave impacts. However, most of these efforts have focused on modeling either selected extreme events or sequences of highly nonlinear waves impacting offshore structures, possibly overestimating the actual load to be experienced by the structure. Overall, not much has been done regarding short-term statistics. Although clear non-Gaussian statistics and therefore higher probabilities of extreme waves have been observed in random seas due to wave–wave interaction phenomena, which can impact short-term statistics for the structural load, they have not been studied extensively regarding the assessment of the dynamic behavior of offshore structures. Computational fluid dynamics (CFD) models have shown their viability for studying wave–structure interaction phenomena. Despite the continuously increasing computational resources, these models remain too computationally demanding for applications to the large spatial domains and long periods of time necessary for studying short-term statistics of non-Gaussian seas. Higher-order spectral (HOS) models, on the other hand, have been proven to be efficient and adequate in studying non-Gaussian seas. We therefore propose a one-way domain decomposition strategy, which takes full advantage of the recent advances in CFD and of the computational benefits of HOS. When applying this domain decomposition strategy, it appeared to be possible to deduce response statistics regarding the impact of nonlinear wave–wave interactions.

A New Coupled Model for the Assessment of Offshore Structures in Non-Gaussian Seas

2020 ◽  
Author(s):  
Griet Decorte ◽  
Alessandro Toffoli ◽  
Geert Lombaert ◽  
Jaak Monbaliu
Keyword(s):  
Coupled Model ◽  
Wave Interaction ◽  
Wave Structure ◽  
Offshore Structures ◽  
Higher Order ◽  
Structure Interaction ◽  
Cfd Models ◽  
Non Gaussian ◽  
Wave Structure Interaction ◽  
Interaction Phenomena

Abstract Although wave-wave interaction phenomena in random seas have shown to lead to a departure from Gaussian statistics and therefore to a higher occurrence of extreme waves, they are usually not taken along in the assessment of the dynamic behaviour of offshore structures. Supported by a rapid increase of computational resources, the use of Computational Fluid Dynamics (CFD) models has become viable for studying the above mentioned wave-structure interaction phenomena. Still, these models remain computationally expensive, which impedes their use for the large domains and the long periods of time necessary for studying non-Gaussian seas. Therefore, a one-way domain decomposition strategy is proposed, which takes advantage of the recent advances in CFD as well as of the computational benefits of the higher-order spectral (HOS) models previously used to assess non-Gaussian seas. The unidirectional non-Gaussian sea obtained by this coupled HOS-CFD model shows excellent agreement with the target wave field generated by the higher-order spectral numerical wave tank. In addition, the wave-structure interaction for a simplified monopile, which is excited by a non-Gaussian sea, seems to be captured well.

Wave Interaction With an Infinite Long Horizontal Elliptical Cylinder

2011 ◽  
Author(s):  
Hao Song ◽  
Longbin Tao
Keyword(s):  
Wave Interaction ◽  
Wave Structure ◽  
Offshore Structures ◽  
Elliptical Cylinder ◽  
Ocean Engineering ◽  
Parallel Side ◽  
Matrix Differential Equations ◽  
Unsteady Loading ◽  
Matrix Differential ◽  
Wave Structure Interaction

Wave-structure interaction in ocean engineering is a major source of unsteady loading and vibration of offshore structures including platforms, risers and long cables. Many efforts focus on vertical structures in which solution procedures can usually be simplified in the plane of mean free surface as the variable in the direction of gravity can be separated. In this paper, wave interaction with an infinite long horizontal elliptical cylinder is solved by a semi-analytical method, namely, the scaled boundary finite-element method (SBFEM). The solution domain is divided into two bounded domains and two unbounded domains with parallel side-faces. The governing partial differential equation (Helmholtz equation) is weakened and transformed to ordinary matrix differential equations in radial direction and are then solved analytically by SBFEM.

One-dimensional analyses of striker impact on bar with different general impedance

2019 ◽  
Vol 234 (2) ◽  
pp. 589-608 ◽  
Author(s):  
Hyunho Shin ◽  
Daesung Kim
Keyword(s):  
Particle Velocity ◽  
Wave Interaction ◽  
One Dimensional ◽  
Release Wave ◽  
Impact Surface ◽  
Impact System ◽  
Multiple Impact ◽  
The Impact ◽  
Primary Pulse ◽  
Interaction Phenomena

The particle velocity and stress in the striker and bar generated by the striker impact on a bar with different general impedance are formulated based on one-dimensional assumptions. Departure of the impact-generated stress wave towards the rear end of the striker and arrival of the release wave from the rear to the front of the striker constitute one impact cycle. In cases where Zs ≤  Zb ( Z is the general impedance, and subscripts ‘s’ and ‘b’ denote striker and bar, respectively), only one impact cycle takes place because the striker is stationary or separated from the impact surface after the first impact cycle. As a result, only a single (primary) pulse is observed in the bar and striker. In the case where Zs >  Zb, however, multiple impact cycles take place because the striker is compressing the bar continually after the first cycle. As a result, a series of step-wise residual pulses follow the primary pulse in the bar and striker. The magnitudes of the stress and particle velocity in the bar and striker calculated using the formulated equations are quantitatively consistent with the results of the numerical simulations, verifying the formulated one-dimensional equations. The equations formulated in this study may be useful for better understanding the various wave interaction phenomena that take place in a pseudo-one-dimensional impact system and for modifying/designing an impact system.

A Newspaper’s Effect on the Strength of Automatic Associations in Memory

2012 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Florian Arendt
Keyword(s):  
Treatment Group ◽  
Term Effect ◽  
Control Group ◽  
Implicit Measure ◽  
Short Term ◽  
Short Term Treatment ◽  
Short Term Effect ◽  
Automatic Associations ◽  
Foreign Nationality ◽  
The Impact

A test was done to see if reading a newspaper which consistently overrepresents foreigners as criminals strengthens the automatic association between foreign country and criminal in memory (i.e., implicit cultivation). Further, an investigation was done to find out if reading articles from the same newspaper produces a short-term effect on the same measure and if (1) emotionalization of the newspaper texts, (2) emotional reactions of the reader (indicated by arousal), and (3) attributed text credibility moderate the short-term treatment effect. Eighty-five participants were assigned to one of three experimental conditions. Participants in the control group received short factual crime texts, where the nationality of the offender was not mentioned. Participants in the factual treatment group received the same texts, but the foreign nationality was mentioned. Participants in the emotionalized treatment group received emotionalized articles (i.e., texts which are high in vividness and frequency) covering the same crimes, with the foreign nationality mentioned. Supporting empirical evidence for implicit cultivation and a short-term effect was found. However, only emotionalized articles produced a short-term effect on the strength of the automatic association, indicating that newspaper texts must have a minimum of stimulus intensity to overcome an effect threshold. There were no moderating effects of arousal or credibility pertaining to the impact on the implicit measure. However, credibility moderated the short-term effect on a first-order judgment (i.e., estimated frequency of foreigners of all criminals). This indicates that a newspaper’s effect on the strength of automatic associations is relatively independent from processes of propositional reasoning.

Diatoms in the Amur Bay sediments (Sea of Japan) and the impact of typhoons on their accumulation over the last 2000 years

2019 ◽  
pp. 252-256
Author(s):  
Irina A. Prushkovskaya ◽  
Ira B. Tsoy
Keyword(s):  
Sea Of Japan ◽  
Short Term ◽  
Catastrophic Events ◽  
Bromine Content ◽  
Amur Bay ◽  
The Impact

The study of diatoms in the sediments of the Amur Bay (Sea of Japan), formed over the last 2000 years, showed that the sharp short-term drops in the concentration of diatoms coincide with the minima of bromine content, which can be explained by the influence of typhoons or other catastrophic events leading to floods and used later in paleoreconstructions.

PENERAPAN CORPORATE SOCIAL RESPONSIBILITY DALAM PENGELOLAAN WAKAF PRODUKTIF

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Masruchin Masruchin
Keyword(s):  
Environmental Impacts ◽  
Infrastructure Development ◽  
Religious Activities ◽  
Short Term ◽  
Local Society ◽  
Business Units ◽  
Corporate Social ◽  
The Impact ◽  
A Company ◽  
Social And Environmental Impacts

Corporate Social Responsibilityis a concept that a company has various forms of responsibility to all stakeholders including consumers, employees, shareholders, communities and the environment in all aspects of the company's operations that include economic, social, and environmental aspects. Therefore CSR is closely related to "sustainable development", in which a company, in carrying out its activities must base its decisions not only on the impact on economic aspects, such as the level of profits or dividends (profits), but also must consider the social and environmental impacts that arise from that decision, both for the short term and the longer term.Pondok Modern Darussalam Gontor (PMDG), in managing its Productive Waqf by establishing business units which mostly involve workers from the local society around PMDG. They are employed according to their skills. This is a form of implementing CSR in order to help advance and improve the welfare of the local society. The existence of these various business units is one of the educational facilities and as a form of CSR application which is actually intended to educate in the fields of independence, entrepreneurship, sincerity and sacrifice.PMDG involvement in social activities that are useful for the local society such as infrastructure development and village facilities, regeneration of students who are from around PMDG to be able to get higher education with funding from the PMDG, doing guidance to the local society through various religious activities, educational and economic activities is a form of PMDG responsibility to the local society environment and also to all stakeholders such as students, Ustadz, employees, so as to provide social and environmental impacts for the short term and the longer term.Keywords: Corporate Social Responsibilityandproductive waqf.

SUMBER-SUMBER RESILIENSI PADA REMAJA AKHIR YANG MENGALAMI KEKERASAN DARI ORANGTUA PADA MASA KANAK-KANAK

Psibernetika ◽  
2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Devina Calista ◽  
Garvin Garvin
Keyword(s):  
Late Adolescents ◽  
Long Term Effects ◽  
Short Term ◽  
Parental Affection ◽  
Resilience Factors ◽  
Childhood Violence ◽  
Past Experiences ◽  
The Impact ◽  
Depth Interviews

<p><em>Child abuse by parents is common in households. The impact of violence on children will bring short-term effects and long-term effects that can be attributed to their various emotional, behavioral and social problems in the future; especially in late adolescence that will enter adulthood. Resilience factors increase the likelihood that adolescents who are victims of childhood violence recover from their past experiences</em><em>,</em><em> become more powerful individuals and have a better life. The purpose of this study was to determine the source of resilience in late adolescents who experienced violence from parents in their childhood. This research uses qualitative research methods with in-depth interviews as a method of data collection. The result shows that the three research participants have the aspects of "I Have", "I Am", and "I Can"; a participant has "I Can" aspects as a source of resilience, and one other subject has no source of resilience. The study concluded that parental affection and acceptance of the past experience have role to the three sources of resilience (I Have, I Am, and I Can)</em></p><p><em> </em></p><p><strong><em>Keyword : </em></strong><em>Resilience, adolescence, violence, parents</em></p>

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