scholarly journals Effect of architectural adjustments on pedestrian flow at bottleneck

2020 ◽  
Vol 5 ◽  
Author(s):  
Jianyu Wang ◽  
Jian Ma ◽  
Peng Lin
Keyword(s):  
Flow Rate ◽  
Average Velocity ◽  
Effective Width ◽  
Pedestrian Flow ◽  
Density Condition ◽  
Fundamental Diagram ◽  
Literature Reviews ◽  
Crowd Evacuation ◽  
Series Of Experiments ◽  
Pedestrian Crowd

In the last decades, a series of terrible accidents happened within pedestrian crowds, which makes crowd dynamic a significant issue to be investigated. Literature reviews show that pedestrian flow presents different features within different architectural layout. In this paper, pedestrian movement properties at bottleneck are studied by carrying out series of experiments under laboratory condition. The influence of door sizes and exit locations on pedestrian crowd flow is investigated. It was found that larger door width resulted in shorter evacuation time and faster flow rate. By comparing the fundamental diagram among crowd evacuation, the average velocity increases as the width increases under the same density condition. Interestingly, the influence of the boundary layer, as well as the effective width on pedestrian crowd dynamic, was clearly observed. Our results suggest that the combination of exit width and location resulted in a synergistic effect, but the exit widths gradually became the most important factor influencing the flow rate.

Effect of speed matching on fundamental diagram of pedestrian flow

2016 ◽  
Vol 458 ◽  
pp. 31-42 ◽  
Author(s):  
Zhijian Fu ◽  
Lin Luo ◽  
Yue Yang ◽  
Yifan Zhuang ◽  
Peitong Zhang ◽  
...  
Keyword(s):  
Pedestrian Flow ◽  
Fundamental Diagram

scholarly journals Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column

2020 ◽  
Vol 10 (13) ◽  
pp. 4617
Author(s):  
Adel Almoslh ◽  
Falah Alobaid ◽  
Christian Heinze ◽  
Bernd Epple
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volumetric Flow Rate ◽  
Interfacial Area ◽  
Gas Flow Rate ◽  
Test Rig ◽  
Flow Rates ◽  
Waste Gas ◽  
Simulated Waste ◽  
Series Of Experiments

The influence of pressure on the gas/liquid interfacial area is investigated in the pressure range of 0.2–0.3 MPa by using a tray column test rig. A simulated waste gas, which consisted of 30% CO2 and 70% air, was used in this study. Distilled water was employed as an absorbent. The temperature of the inlet water was 19 °C. The inlet volumetric flow rate of water was 0.17 m3/h. Two series of experiments were performed; the first series was performed at inlet gas flow rate 15 Nm3/h, whereas the second series was at 20 Nm3/h of inlet gas flow rate. The results showed that the gas/liquid interfacial area decreases when the total pressure is increased. The effect of pressure on the gas/liquid interfacial area at high inlet volumetric gas flow rates is more significant than at low inlet volumetric gas flow rates. The authors studied the effect of decreasing the interfacial area on the performance of a tray column for CO2 capture.

Modelling of Pedestrian Speed-Density and Volume-Density Relationships in Outdoor Walkways

2015 ◽  
Vol 73 (4) ◽  
Author(s):  
Hashim Mohammed Alhassan ◽  
Nordiana Mashros
Keyword(s):  
Adult Female ◽  
Flow Rate ◽  
Adult Male ◽  
Young Male ◽  
The United States ◽  
Young Female ◽  
Pedestrian Flow ◽  
Flow Parameters ◽  
City District ◽  
The City

The aim of this study was to model pedestrian flow parameters needed in the design of pedestrian facilities. The study also characterized the flow with a view to understanding pedestrian interaction problems especially with regards to their congestion. Twenty-five locations across Kano metropolis were selected for study, thirteen locations from the city district while twelve sites were chosen from the Waje district. All the sites were high flow pedestrian locations that met the study objectives. The data was categorized into four; young male, adult male, young female and adult female. The results indicated that adult women walked faster than their male counterparts in the City district while young males were faster than the female. The adult female recorded an average speed of 73.90 m/min against the speed of 71.30 m/min for the adult male. The average characteristics of the pedestrian in the city district are speed 67.30 m/min; density 11.23 Ped/m2 and volume 33.60 Ped/m/min. In the Waje district, however, the male pedestrian whether adult or young walked faster than their corresponding female counterparts with speed of 71.45 m/min for the adult male and 59.90 m/min for the adult female. The young male was faster than the young female by 17.9%. The average pedestrian flow parameters for the Waje district indicated a combine speed of 60.21 m/min; density of 8.72 Ped/m2 and volume of 30.92 Ped/m/min. The pedestrians in the city district had a higher flow rate, higher density and higher speed than those of the Waje district. This means the city district is a little more concentrated than the Waje district in terms of pedestrian flow. The aggregate average flow parameters of pedestrians in the metropolitan area gave the following parameters: speed 68.92 m/min; density 10.03 Ped/m2 and volume 32.33 Ped/m/min. The predictive models for Kano showed a free flow speed of 59.55 m/min and a maximum flow rate of 73.0 Ped/m/min. Comparing the Kano pedestrian model with other countries it was found that the Kano pedestrian walked slower than pedestrians from Singapore and the United States

Design and Testing of a Linear-Driven Electro-Hydrostatic Actuator

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Zimeng Wang ◽  
Zongxia Jiao ◽  
Xinglu Li
Keyword(s):  
Flow Rate ◽  
Rate Equation ◽  
High Frequency ◽  
Reciprocating Motion ◽  
Series Of Experiments ◽  
Spool Valves ◽  
Design And Testing

Abstract This paper presents a novel hydrostatic actuator, which is named as linear-driven electro-hydrostatic actuator (LEHA). In an LEHA, the actuator is driven by a novel collaborative rectification pump (CRP), which incorporates two miniature cylinders and two spool valves. Specifically, the CRP is driven by two linear oscillating motors, which are designed and optimized to generate reciprocating motion at high frequency with adequate stroke. CRP offers a highly novel linear fluid pump with flexibility in bi-directionally driving. In this paper, schematic of LEHA is first presented and its kinematic flow rate equation is derived. Then the design of CRP, linear oscillating motor, as well as the whole LEHA prototype is introduced. Performance of the LEHA is demonstrated through a series of experiments and simulation, and analysis of the results is also included.

Study about influence of doors’ opening degree on crowd evacuation based on simulation

2019 ◽  
Vol 30 (11) ◽  
pp. 1950096
Author(s):  
Yuanchun Ding ◽  
Falu Weng ◽  
Lizhong Yang
Keyword(s):  
Linear Relationship ◽  
Flow Rate ◽  
Saving Rate ◽  
Mean Square ◽  
Mean Flow ◽  
Time Saving ◽  
Evacuation Time ◽  
Crowd Evacuation ◽  
The Mean ◽  
Simulation Results

Based on simulation, the influence of the doors’ opening degree (DOD) on crowd evacuation is investigated in this paper. First of all, an evacuation model, which has one exit with two doors, is established by utilizing the software Pathfinder. Then, based on the obtained model, some evacuation scenarios are considered. The simulation results indicate, when the DOD is within 115∘–135∘, the time saving rate is more than 13%, and the maximum time saving rate is achieved when the DOD is 125∘. Furthermore, there is a linear relationship between the mean square error and the number of the evacuees. For a small number of evacuees, the total evacuation time is mainly influenced by the distributions of the evacuees, however, as the number of the evacuees increases, it is mainly influenced by the number of the evacuees. Moreover, when the DOD is 125∘, the mean flow rate per unit width (MFRPUW) decreases along with the increasing of exit’s width, however, it increases along with the increasing of exit’s width while the DOD is 180∘. Compared with the 180∘ DOD, the 125∘ DOD can always achieve a higher MFRPUW, and the narrower the exit is, the higher MFRPUW the 125∘ DOD achieves.

A study of group effects in pedestrian crowd evacuation: Experiments, modelling and simulation

2021 ◽  
Vol 133 ◽  
pp. 105029
Author(s):  
Wei Xie ◽  
Eric Wai Ming Lee ◽  
Tao Li ◽  
Meng Shi ◽  
Ruifeng Cao ◽  
...  
Keyword(s):  
Modelling And Simulation ◽  
Crowd Evacuation ◽  
Pedestrian Crowd ◽  
Group Effects

Recent Knowledge From an Experimental Investigation on Self-Leveling Behavior of Debris Bed

2013 ◽  
Author(s):  
Songbai Cheng ◽  
Hidemasa Yamano ◽  
Tohru Suzuki ◽  
Yoshiharu Tobita ◽  
Yuya Nakamura ◽  
...  
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Gas Flow ◽  
Particle Density ◽  
The Self ◽  
Gas Flow Rate ◽  
Energy Agency ◽  
Experimental Parameters ◽  
The Status ◽  
Series Of Experiments

Studies on the self-leveling behavior of debris bed are crucial in the assessment of core-disruptive accident (CDA) that could occur in sodium-cooled fast reactors (SFR). To clarify the mechanisms of this behavior, several series of experiments were elaborately designed and performed in recent years under the collaboration between Japan Atomic Energy Agency (JAEA) and Kyushu University (Japan). This paper presents the recent knowledge obtained from the newly developed large-scale experiments using gas-injection to simulate coolant boiling. Compared to previous investigations, it can cover a much wider range of gas velocities (presently up to a flow rate of around 300L/min). Based on the experimental data obtained, influence of various experimental parameters, including gas flow rate (∼ 300 L/min), water depth (180 mm and 400mm), bed volume (5L, 7L), particle size (2 ∼ 6 mm), particle density (beads of alumina, zirconia and stainless steel) along with particle shape (spherical and irregularly-shaped) on the leveling was checked and compared. In addition, the status of developing empirical model to predict the self-leveling over current setup was also presented. This work, which gives a large palette of favorable data for a better understanding and an improved estimation of CDAs in SFRs, is expected to benefit future analyses and verifications of computer models developed in advanced fast reactor safety analysis codes.

scholarly journals Interruption of machine milking in dairy cows: effects on intramammary pressure and milking characteristics

1995 ◽  
Vol 62 (4) ◽  
pp. 559-566 ◽  
Author(s):  
Hans-Ulrich Pfeilsticker ◽  
Rupert M. Bruckmaier ◽  
Jürg W. Blum
Keyword(s):  
Milk Yield ◽  
Flow Rate ◽  
Removal Rate ◽  
Total Yield ◽  
Machine Milking ◽  
Ejection Rate ◽  
Milk Flow ◽  
Total Milk ◽  
Series Of Experiments ◽  
Milking Machine

SUMMARYExperiments were designed to test the hypothesis that milk ejection rate decreases during milking, thereby causing insufficient refill of the cistern and decreasing milk flow rate towards the end of milking. In a first series of experiments machine milking of the left front quarters of 11 cows was interrupted for 2 min after removal of 25, 50 or 75% of expected total milk yield, while milking was continued in the other three quarters. Milk flow was recorded during machine-on times. Intramammary pressure (IMP) was recorded during premilking teat stimulation and during interruption of milking. IMP during interruption of milking decreased with decreasing amounts of milk remaining in the udder. The IMP did not change during these interruptions when they occurred after 25 and 50% of expected total milk yield was removed. Thus, the ejection rate could keep up with the milk flow or removal rate. However, IMP increased during interruption of milking following removal of 75% of total yield, although significantly so only in cows with a high milk flow rate. Obviously, more milk was removed than was transported to the cisternal cavity. It is likely that a reduced ejection rate caused the decreased milk flow rate. In a second series of experiments the pulsation ratio of the milking machine was changed from the usual 70:30 to 50:50 with the aim of reducing the milk flow rate and thus adapting to the ejection rate at the end of milking. The changed pulsation ratio caused a reduced peak flow rate and a prolonged high milk flow period, whereas the main flow rate did not change significantly.

scholarly journals THE HYDRAULICS OF NATURE-LIKE FISHWAYS

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Xi Mao ◽  
Sheng Huang ◽  
Yuchen Xu ◽  
Zhong Cheng ◽  
Jiehao Zhang
Keyword(s):  
Flow Rate ◽  
Average Velocity ◽  
Head Loss ◽  
Main Flow ◽  
Physical Models ◽  
Hydraulic Structures ◽  
Type I ◽  
Type Ii ◽  
Periodic Fluctuations ◽  
Natural Rivers

Nature-like fishway arrangements are commonly used because these structures imitate the characteristics of natural rivers and effectively allow fish to migrate past river sections blocked by hydraulic structures. In this paper, physical models were analyzed, and the velocity distributions of two different fishway structures (Types I and II) were compared. Results showed that the maximum mainstream velocity of the Type I structure was 5.3% lower than that of the Type II structure. However, the average mainstream velocity of the Type I structure was 21.1% greater than that of the Type II structure. The total per-cycle length of the mainstream path in the Type II structure was 2.1 times greater than that of the Type I structure, which indicated that the length of the mainstream path was somewhat proportional to the average velocity of the mainstream. When the flow rate was kept constant, increases in the velocity of the main flow associated with changes in the internal structure of the fishway decreased the average velocity of the main flow, while decreases in the total length of the flow path led to increases in the average velocity of the main flow. Due to frictional head loss along the fishway and local head loss, as well as the overlaps between these factors, the overall flow rate gradually decreased every cycle, despite periodic fluctuations.

scholarly journals A new framework for high-resolution pedestrian data processing using rule-based algorithms and real-time alarm systems

2020 ◽  
Vol 5 ◽  
pp. A99
Author(s):  
Michael Moos ◽  
Basil Vitins ◽  
Mirwais Tayebi ◽  
Lukas Gamper ◽  
Julia Wysling ◽  
...  
Keyword(s):  
Data Processing ◽  
Real Time ◽  
Safety Evaluation ◽  
Processing System ◽  
Strategic Communication ◽  
Sensor Data ◽  
Shopping Centers ◽  
Pedestrian Flow ◽  
Fundamental Diagram ◽  
Technological Advances

Pedestrian flows and densities have increased in recent years within transport-related public facilities such as train stations, as well as in private buildings such as shopping centers, event halls or convention centers. Increasing flows and high densities often raise comfort, safety, operational and delay issues; and therefore, require pedestrian flow optimization, intervention or even revised regulation. Recent technological advances enhanced pedestrian sensing; however, they disregard adaptive data capture, processing, and strategic communication within reasonable time, or real-time, such as tactic occupancy or density alarms trigger rules. Content of this research is twofold. First, new data capturing and processing advances of recent technological developments are combined in an integral software and hardware-based framework. Second, applied methods highlight projects and experiences on both pedestrian research and on existing and operating pedestrian facilities. Based on the described, two-sided approach, proposed framework is able to fulfil high safety and comfort standards of facilities such as train stations, retail facilities or event halls. In this research, past semi-automatic video analysis processing of pedestrian behavioral studies is replaced with combined sensor and data processing system within proposed framework. In train stations of major operators, real-time pedestrian observation increases safety levels on station platforms. Tactic algorithms and alarm trigger schemes enable on-time surveillance, e.g. at overcrowded floor levels in shopping centers for escalator or door closure. Sensor data is used to train models for underpass pedestrian flow regarding path choice and fundamental diagram. In retail, queue length, trajectory analysis and floor occupancy are determined for economic, comfort as well as safety evaluation. Using trajectory classification, movement and dwell time is analyzed for staff and visitors separately (see Figure 1).

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