Numerical Analysis of Fluid-Structure Interaction of Frame Structure Considering the Impact of Turbulent Wind Load

2011 ◽  
Vol 94-96 ◽  
pp. 2130-2133
Author(s):  
Wen Bin Sun
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Coupling Effect ◽  
Frame Structure ◽  
Vortex Induced Vibration ◽  
Vibration Effect ◽  
Control Principle ◽  
And Control ◽  
Wind Induced Vibration ◽  
The Impact

According to the basic principle of CFD simulation and methods, a framework structure was studied for its vortex-induced vibration and control principle of around the flow field, it revealed the characteristics of vortex-induced vibration and rules, systematically studied frame structure fluid-solid coupling effect and the flow field active control methods and mechanism. Results provide the theory basis for the frame structure around the flow field and the wind induced vibration effect.

Axial Load on the Submarine Pipeline Suspended Law of Vortex Induced Vibration

2011 ◽  
Vol 94-96 ◽  
pp. 1511-1514
Author(s):  
Yi Fei Yan
Keyword(s):  
Natural Frequency ◽  
Axial Force ◽  
Scientific Basis ◽  
Oil Field ◽  
Span Length ◽  
Submarine Pipeline ◽  
Vortex Induced Vibration ◽  
Vibration Effect ◽  
Pipeline Vibration ◽  
The Impact

The study is about submarine pipeline. Considering the impact of different axial force, The reduced velocity is introduced as the pipeline vibration effect of vortex trail releasing. The vibration parameters of the span pipeline are analyzed and vibration control formula is built. The natural span length of the submarine pipeline is calculated according to the DNV-OS-F101 rule. The natural frequency of the span pipeline and the allowable span length are solved. The case study of submarine pipeline in Chengdao oil field is made and the variation law of natural frequency of span pipeline is got. The stream reduced velocity decreases as the axial force increase. The theory analysis of the vortex induced vibration can provide the scientific basis for the safety design of offshore submarine pipeline.

scholarly journals CFD Simulation and Performance Investigation on a Novel Bionic Spider-Web-Type Flow Field for PEM Fuel Cells

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1526
Author(s):  
Qizhen Xie ◽  
Minggang Zheng
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Cfd Simulation ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Cathode Side ◽  
Spider Web ◽  
Polygonal Structure ◽  
Type Flow ◽  
The Impact

The products generated by the electrochemical reaction in the PEM fuel cell (PEMFC) are mainly concentrated in the flow field on the cathode side of the bipolar plate, and the oxygen introduced on the cathode has higher requirements to improve its diffusion performance by using the flow field structure. For this reason, the optimization of the cathode flow field of the PEMFC is essential. Inspired by the structure of a spider web, this paper proposes a novel spider-web-type flow field. In this kind of flow field, the shape of a polygonal structure and the number of layers of spiral flow channels are the two most crucial variables. In order to explore the impact of these two variables on the cathode flow field, complete three-dimensional PEMFC models with different values of the two variables were established, and the models were simulated by the method of CFD. By observing the results of oxygen distribution, the water removal performance and fuel cell output performance of different schemes, the optimal scheme of the polygonal structure and layer number are determined. Compared with the traditional flow field, it is proved that the optimization scheme is desirable in improving the performance of the cathode flow field in PEMFC.

Flow Field Characteristics Simulation of the Exhaust Hood

2012 ◽  
Vol 557-559 ◽  
pp. 2261-2265
Author(s):  
Ru Shan Ren ◽  
Da Hua Jiang ◽  
Fa En Shi ◽  
Yun Chao Zhao
Keyword(s):  
Mathematical Model ◽  
Flow Field ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Exhaust Hood ◽  
Indoor Temperature ◽  
Conditioning Treatment ◽  
Cooking Fume ◽  
Flow Field Characteristics ◽  
And Control

Cooking fume(CF) with harmful pollutants and heat is paid more attention to by many peple. Physical and mathematical model are established on the basis of standard kitchen, and flow field characteristics(FFC) of the exhaust hood(EH) is simulated by CFD. Simulation of flow field of the EH indicates that, reasonable air exhaust rate(AER) is made for emissions of pollutants in kitchen; the effect of grille on flow field of the EH is obvious; the EH height selected correctly is beneficial to enhance the capture efficiency, and the exhaust effect will be strengthened. Air conditioning treatment should be applied in the kitchen and will be beneficial to decrease the indoor temperature of the kitchen and control pollutant concentration.

scholarly journals A 2–D Mathematical Model of Vortex Induced Vibration Driven Bladeless Wind Turbine

2019 ◽  
Vol 291 ◽  
pp. 02007
Author(s):  
Sirada Saengsaen ◽  
Chawin Chantharasenawong ◽  
Tsung-Liang Wu
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Structural Vibration ◽  
Detached Eddy Simulation ◽  
Vortex Induced Vibration ◽  
Cylindrical Structures ◽  
Shear Stress Transport

Bladeless wind turbine (BWT) is a flexible cylindrical structure that extracts energy from wind by utilising vortex-induced vibration (VIV) - aerodynamic forces and the resulting structural vibration. This work focuses on taking possible advantage of the increase in lift forces in the similar fashion to birds flying in a V-formation. The purposes of the present study are 1) to study the flow pattern and characteristic around two BWTs which are cylindrical structures in the same flow field and 2) to study the extra lift force generation of the system. 2–D CFD models are used to simulate flow of stationary cylinder of BWTs at Re = 105. The two different turbulent models, Reynolds Averaged Navier-Stokes shear-stress transport k(RANS–SST k) and Detached Eddy Simulation shear-stress transport k(DES–SST k) are investigated. The results show that only DES–SST kgives converged results, therefore, DES–SST kis selected for the additional studies of two cylindrical structures. From 2–D CFD simulation, the one BWT in flow field case produces lift coefficient 0.851. In the case of two BTWs in same flow field (BWT no.2 is located at x = 3D, y = 0D, directly downstream of two cylinders), BTW no.1 and BWT no.2 show greater lift coefficients of 0.893 and 1.841, respectively. This result indicates that the kinetic energy generation of the downstream BWT in the two BWTs system in this study is greater than the baseline BWT with an increase of 116% of lift. Further work is needed to determine the optimum location of the behind wind turbine for greater lift and result to increasing of energy produce of the system.

The Impact of Water Distribution System on the Internal Flow Field of EGSB by Using CFD Simulation

2014 ◽  
Vol 614 ◽  
pp. 596-604 ◽  
Author(s):  
Hua Wang ◽  
Jie Ding ◽  
Xian Shu Liu ◽  
Nan Qi Ren
Keyword(s):  
Flow Field ◽  
Distribution System ◽  
Water Distribution ◽  
Cfd Simulation ◽  
Water Distribution System ◽  
Fluid Model ◽  
Internal Flow ◽  
Granular Sludge ◽  
Flow State ◽  
The Impact

The internal flow field of EGSB (Expanded Granular Sludge Bed) reactor was investigated by using CFD simulation. A three-dimensional Eulerian–Eulerian two phase (sewage-granular sludge) fluid model was applied to investigate the impact of water distribution system on the internal flow field by considering the ratio α of hole area to reactor area. Results showed that the flow state of sludge granules changed periodically when the sludge bed reached a stabilization stage, and every cycle included two periods (U period and D period), where U stands for up-flow of the granular sludge and D represents down-flow. Keeping the upward-flow velocity of reactor at 3 m/h and reducing ratio α from 1.44% to 0.25%, the flow state of the two periods changed differently and was closely related to the height of reactor. Besides, the ratio α could affect the homogeneity of sludge granules, which could further influence the performance of the reactor. In addition, a validation experiment was conducted to verify the practical applicability of the fluid model, a good relationship between simulation and experiment was discovered, which further confirmed that the ratio α of water distribution system has significant impact on the internal flow field of EGSB.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

Research Participation Experiences of Informants of Suicide and Control Cases

Crisis ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. 238-246 ◽  
Author(s):  
Paul W. C. Wong ◽  
Wincy S. C. Chan ◽  
Philip S. L. Beh ◽  
Fiona W. S. Yau ◽  
Paul S. F. Yip ◽  
...  
Keyword(s):  
Ethical Issues ◽  
Research Participation ◽  
Self Report ◽  
Initial Contact ◽  
Psychological Autopsy ◽  
Autopsy Study ◽  
The People ◽  
And Control ◽  
The Impact

Background: Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. Aims: (1) To investigate whether informants of suicide cases recruited by two approaches (coroners’ court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. Methods: A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. Results: The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. Limitations: The acceptance rate for our original psychological autopsy study was modest. Conclusions: The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

Using Work Domain Analysis to Evaluate the Impact of Digitization on Command and Control

2008 ◽  
Author(s):  
Daniel P. Jenkins ◽  
Neville A. Stanton ◽  
Paul M. Salmon ◽  
Guy H. Walker
Keyword(s):  
Command And Control ◽  
Domain Analysis ◽  
Work Domain Analysis ◽  
And Control ◽  
The Impact ◽  
Work Domain

Experimental Study of the Impact of Alisma plantago-aquatica Secretions on Pathogenic Bacteria

2014 ◽  
Vol 1 (3) ◽  
pp. 3-7
Author(s):  
O. Zhukorskyy ◽  
O. Hulay
Keyword(s):  
Pathogenic Bacteria ◽  
Initial Density ◽  
Biologically Active ◽  
Erysipelothrix Rhusiopathiae ◽  
Natural Focus ◽  
Test Species ◽  
Popula Tions ◽  
And Control ◽  
The Impact

Aim. To estimate the impact of in vivo secretions of water plantain (Alisma plantago-aquatica) on the popula- tions of pathogenic bacteria Erysipelothrix rhusiopathiae. Methods. The plants were isolated from their natural conditions, the roots were washed from the substrate residues and cultivated in laboratory conditions for 10 days to heal the damage. Then the water was changed; seven days later the selected samples were sterilized using fi lters with 0.2 μm pore diameter. The dilution of water plantain root diffusates in the experimental samples was 1:10–1:10,000. The initial density of E. rhusiopathiae bacteria populations was the same for both experimental and control samples. The estimation of the results was conducted 48 hours later. Results. When the dilution of root diffusates was 1:10, the density of erysipelothrixes in the experimental samples was 11.26 times higher than that of the control, on average, the dilution of 1:100 − 6.16 times higher, 1:1000 – 3.22 times higher, 1:10,000 – 1.81 times higher, respectively. Conclusions. The plants of A. plantago-aquatica species are capable of affecting the populations of E. rhusiopathiae pathogenic bacteria via the secretion of biologically active substances into the environment. The consequences of this interaction are positive for the abovementioned bacteria, which is demon- strated by the increase in the density of their populations in the experiment compared to the control. The intensity of the stimulating effect on the populations of E. rhusiopathiae in the root diffusates of A. plantago-aquatica is re- ciprocally dependent on the degree of their dilution. The investigated impact of water plantain on erysipelothrixes should be related to the topical type of biocenotic connections, the formation of which between the test species in the ecosystems might promote maintaining the potential of natural focus of rabies. Keywords: Alisma plantago-aquatica, in vivo secretions, Erysipelothrix rhusiopathiae, population density, topical type of connections.

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