A Review of Flow-Induced Vibration of Two Circular Cylinders in Crossflow

1986 ◽  
Vol 108 (4) ◽  
pp. 382-393 ◽  
Author(s):  
S. S. Chen
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Dynamic Response ◽  
Flow Regimes ◽  
Circular Cylinders ◽  
Future Research ◽  
Research Needs ◽  
Flow Induced Vibration ◽  
Excited Vibration ◽  
Staggered Arrangement

The flow field around a pair of rigid circular cylinders is very complex and has been studied extensively. When either one or both cylinders vibrate, the flow field becomes significantly more complicated because of the interaction of the fluid flow and the cylinder motion. This paper presents an overview of the problem including different flow regimes, vortex-excited vibration, and fluidelastic instability for two cylinders in tandem, two cylinders side by side and two cylinders in staggered arrangement. A general formulation to study dynamic response under different conditions is outlined and future research needs are discussed.

Flow-Induced Vibration of Cross-Shaped Tube Bundle: The Effect of Tube Bundle Arrangement

2003 ◽  
Author(s):  
Fumio Inada ◽  
Takashi Nishihara ◽  
Akira Yasuo ◽  
Ryo Morita ◽  
Akihiro Sakashita ◽  
...  
Keyword(s):  
Correlation Length ◽  
Random Vibration ◽  
Tube Bundle ◽  
Cross Flow ◽  
Flow Induced Vibration ◽  
Power Spectral ◽  
Shaped Tube ◽  
Excited Vibration ◽  
Power Spectral Densities ◽  
Staggered Arrangement

A cross-shaped tube bundle is proposed for the lower plenum structure in the next-generation LWR. The effect of tube bundle arrangement on the flow-induced vibration characteristics of the cross-shaped tube bundle in cross flow was considered experimentally. Regarding random vibration, the power spectral density of the fluid force of the staggered arrangement as well as the correlation length was measured and those of the normal arrangement were compared with those of the staggered arrangement. Regarding self-excited vibration, vibration response was compared. The trend of the power spectral densities, correlation length, and the critical velocity of the normal arrangement were similar to those of the staggered arrangement.

Pulsating Flow Induced Vibration in the Seal System

2014 ◽  
Vol 602-605 ◽  
pp. 642-645
Author(s):  
Nan Zhang
Keyword(s):  
Fluid Flow ◽  
Nonlinear Models ◽  
Point Of View ◽  
The Self ◽  
Oscillating Flow ◽  
Nonlinear Phenomena ◽  
Flow Induced Vibration ◽  
Nonlinear Characteristics ◽  
Unbalanced Rotor ◽  
Excited Vibration

The oscillating flow is an important factor affecting the performance of the rotor–seal system. From the point of view of flow induced vibration, the nonlinear models of the rotor-seal system are presented for the analysis of the self-excited vibration, which is induced by interaction between the unstable seal fluid flow and the vibrating rotor. The nonlinear characteristics of flow induced vibration in the rotor-seal system are analyzed, and the nonlinear phenomena in the unbalanced rotor-seal system are investigated using the nonlinear model with the flow induced vibration.

Flow Induced Vibration in the Seal System

2014 ◽  
Vol 644-650 ◽  
pp. 390-393
Author(s):  
Nan Zhang
Keyword(s):  
Fluid Flow ◽  
Nonlinear Models ◽  
Point Of View ◽  
The Self ◽  
Oscillating Flow ◽  
Nonlinear Phenomena ◽  
Flow Induced Vibration ◽  
Nonlinear Characteristics ◽  
Unbalanced Rotor ◽  
Excited Vibration

The oscillating flow is an important factor affecting the performance of the rotor–seal system. From the point of view of flow induced vibration, the nonlinear models of the rotor-seal system are presented for the analysis of the self-excited vibration, which is induced by interaction between the unstable seal fluid flow and the vibrating rotor. The nonlinear characteristics of flow induced vibration in the rotor-seal system are analyzed, and the nonlinear phenomena in the unbalanced rotor-seal system are investigated using the nonlinear model with the flow induced vibration.

Oscillatory flow regimes around four cylinders in a square arrangement under small and conditions

2015 ◽  
Vol 769 ◽  
pp. 298-336 ◽  
Author(s):  
Feifei Tong ◽  
Liang Cheng ◽  
Ming Zhao ◽  
Hongwei An
Keyword(s):  
Flow Field ◽  
Oscillatory Flow ◽  
Flow Regimes ◽  
Reynolds Numbers ◽  
Flow Patterns ◽  
Hydrodynamic Forces ◽  
Circular Cylinders ◽  
Single Cylinder ◽  
Wake Interference ◽  
Spatio Temporal

Sinusoidally oscillatory flow around four circular cylinders in an in-line square arrangement is numerically investigated at Keulegan–Carpenter numbers ($\mathit{KC}$) ranging from 1 to 12 and at Reynolds numbers ($\mathit{Re}$) from 20 to 200. A set of flow patterns is observed and classified based on known oscillatory flow regimes around a single cylinder. These include six types of reflection symmetry regimes to the axis of flow oscillation, two types of spatio-temporal symmetry regimes and a series of symmetry-breaking flow patterns. In general, at small gap distances, the four structures behave more like a single body, and the flow fields therefore resemble those around a single cylinder with a large effective cylinder diameter. With increasing gap distance, flow structures around each individual cylinder in the array start to influence the overall flow patterns, and the flow field shows a variety of symmetry and asymmetry patterns as a result of vortex and shear layer interactions. The characteristics of hydrodynamic forces on individual cylinders as well as on the cylinder group are also examined. It is found that the hydrodynamic forces respond in a similar manner to the flow field to the cylinder proximity and wake interference.

Understanding Limited Use of Amplification in Infants and Children Who Are Hard of Hearing

2015 ◽  
Vol 25 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Ryan W. McCreery ◽  
Elizabeth A. Walker ◽  
Meredith Spratford
Keyword(s):  
Hard Of Hearing ◽  
Hearing Aid ◽  
Management Strategies ◽  
Infants And Children ◽  
Future Research ◽  
Research Needs ◽  
Case Examples ◽  
Hearing Aid Use ◽  
Wide Range ◽  
In Infants And Children

The effectiveness of amplification for infants and children can be mediated by how much the child uses the device. Existing research suggests that establishing hearing aid use can be challenging. A wide range of factors can influence hearing aid use in children, including the child's age, degree of hearing loss, and socioeconomic status. Audiological interventions, including using validated prescriptive approaches and verification, performing on-going training and orientation, and communicating with caregivers about hearing aid use can also increase hearing aid use by infants and children. Case examples are used to highlight the factors that influence hearing aid use. Potential management strategies and future research needs are also discussed.

Locus of Control, Safety Attitudes and Involvement in Hazardous Events in Indian Army Aviators

2013 ◽  
Vol 3 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Catherine Joseph ◽  
Suhasini Reddy ◽  
Kanwal Kashore Sharma
Keyword(s):  
Locus Of Control ◽  
Future Research ◽  
Research Needs ◽  
Negative Attitudes ◽  
Human Errors ◽  
Safety Attitudes ◽  
Positive Correlation ◽  
Self Confidence

Locus of control (LOC), safety attitudes, and involvement in hazardous events were studied in 205 Indian Army aviators using a questionnaire-based method. A positive correlation was found between external LOC and involvement in hazardous events. Higher impulsivity and anxiety, and decreased self-confidence, safety orientation, and denial were associated with a greater number of hazardous events. Higher external LOC was associated with higher impulsivity, anxiety, and weather anxiety and with lower self-confidence, safety orientation, and denial. Internal LOC was associated with increased self-confidence, safety orientation, and denial. Hazardous events and self-confidence were higher in those involved in accidents than those not involved in accidents. Future research needs to address whether training can effectively modify LOC and negative attitudes, and whether this would cause a reduction in, and better management of, human errors.

Collaborative Remembering in Dementia: A Focus on Joint Activities

2018 ◽  
Author(s):  
Lars-Christer Hydén ◽  
Mattias Forsblad
Keyword(s):  
Everyday Life ◽  
Past Research ◽  
Research Field ◽  
Future Research ◽  
Research Needs ◽  
Joint Activities ◽  
Do So ◽  
Dementia Diseases

In this chapter we consider collaborative remembering and joint activates in everyday life in the case of people living with dementia. First, we review past research of practices that scaffolds the participation of persons with dementia in everyday chores under different stages of dementia diseases. We do so by suggesting three analytical types of scaffolding: when the scaffolding practices (i) frame the activity, (ii) guide actions, or (iii) are part of repair activities. Second, we review two aspects of collaborative remembering that are especially important in the case of dementia: training of scaffolding practices, and the sustaining and presentation of identities through collaborative storytelling. Finally, theoretical and methodological tendencies of the research field are summarized and future research needs are formulated.

A Scoping Review of Resilience in Survivors of Human Trafficking

2021 ◽  
pp. 152483802098556
Author(s):  
Logan Knight ◽  
Yitong Xin ◽  
Cecilia Mengo
Keyword(s):  
Interpersonal Relationships ◽  
Scoping Review ◽  
National Origin ◽  
Future Research ◽  
Research Needs ◽  
Standardized Measures ◽  
Factors Associated ◽  
Current State ◽  
Case Files ◽  
Sexual Trafficking

Resilience is critical among survivors of trafficking as they are mostly vulnerable populations who face multiple adversities before, during, and after trafficking. However, resilience in survivors of trafficking is understudied. This scoping review aims to clarify the current state of knowledge, focusing on definitions of resilience, how resilience has been studied, and factors associated with resilience among survivors. Five databases were searched using key words related to trafficking and resilience. Studies were included if they were published in English between 2000 and 2019 and focused on resilience with the study design including at least one of these four features: (a) use of standardized measures of resilience, (b) qualitative descriptions of resilience, (c) participants were survivors or professionals serving survivors, and (d) data sources such as case files or program manuals directly pertained to survivors. Eighteen studies were identified. Findings indicated that resilience was primarily described as emergent from interactions between the survivor and the environment. Resilience in trafficking appeared largely similar to resilience in other kinds of victimization. Nonetheless, trafficking survivors also may display resilience in alternative ways such as refusing treatment. Positive interpersonal relationships were the most commonly mentioned resilience factor. In addition, current research lacks studies featuring longitudinal designs, interventions, participatory methods, types of trafficking other than sexual trafficking, and demographic characteristics such as age, gender, and national origin. Future research needs to establish definitions and measures of resilience that are culturally and contextually relevant to survivors and build knowledge necessary for designing and evaluating resilience-enhancing interventions.

scholarly journals Endocrine Disrupting Chemicals: Current Understanding, New Testing Strategies and Future Research Needs

2021 ◽  
Vol 22 (2) ◽  
pp. 933
Author(s):  
Maria E. Street ◽  
Karine Audouze ◽  
Juliette Legler ◽  
Hideko Sone ◽  
Paola Palanza
Keyword(s):  
Endocrine Disrupting Chemicals ◽  
Endocrine System ◽  
Current Understanding ◽  
Future Research ◽  
Developmental Origins ◽  
Research Needs ◽  
Important Class ◽  
Testing Strategies ◽  
Endocrine Disrupting ◽  
Health And Disease

Endocrine disrupting chemicals (EDCs) are exogenous chemicals which can disrupt any action of the endocrine system, and are an important class of substances which play a role in the Developmental Origins of Health and Disease (DOHaD) [...]

scholarly journals Risks of Covid-19 face masks to wildlife: Present and future research needs

2021 ◽  
pp. 148505
Author(s):  
Ana L. Patrício Silva ◽  
Joana C. Prata ◽  
Catherine Mouneyrac ◽  
Damià Barcelò ◽  
Armando C. Duarte ◽  
...  
Keyword(s):  
Future Research ◽  
Research Needs
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