scholarly journals Field measurement and numerical simulation of the relationship between the vertical wind environment and building morphology in residential areas in Xi’an, China

2021 ◽  
Author(s):  
Wei Feng ◽  
Meng Zhen ◽  
Wei Ding ◽  
Qishu Zou
Keyword(s):  
Numerical Simulation ◽  
Field Measurement ◽  
Vertical Wind ◽  
Residential Areas ◽  
Wind Environment ◽  
The Relationship

scholarly journals Field Measurement and Numerical Simulation of the Relationship Between Vertical Wind Environment and Building Morphology in Residential Areas in Xi’an, China

2021 ◽  
Author(s):  
Wei Feng ◽  
Meng Zhen ◽  
Wei Ding ◽  
Qishu Zou
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Residential Buildings ◽  
Residential Area ◽  
Vertical Wind ◽  
Residential Areas ◽  
Building Height ◽  
Ventilation Efficiency ◽  
Morphological Index ◽  
The Impact

Abstract The inadequate consideration of the impact of building morphology on ventilation efficiency in many urban residential areas has resulted in a series of environmental problems that threaten human health. The purpose of this paper is to establish a prediction model between ventilation efficiency and building forms in residential areas. Firstly, the characteristics of vertical wind profile in residential areas are measured through unmanned aerial vehicle (UAV); secondly, the wind speed ratio (WSR) at different height levels under the impact of morphological index (floor area ratio, building density, average building height, enclosure degree, height fall and maximum building height) in the residential area is simulated by ENVI-met; finally, two kinds of prediction formulas are obtained: (1) the average ventilation efficiency at the pedestrian level and (2) the prediction formula of WSR at different heights. The results show that the wind speed (WS) in residential area below 35 m is about 0.6 m/s lower than that in park. The results of numerical simulation show that the mean WSR at the pedestrian level is negatively correlated with each index and the height fall morphological index has the greatest impact on the WSR at different heights. The research can provide a reference for the optimal planning and design of ventilation efficiency of residential buildings, especially those in static wind areas.

scholarly journals A Field Measurement Based Wind Characteristics Analysis of a Typhoon in Near-Ground Boundary Layer

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 873
Author(s):  
Dandan Xia ◽  
Liming Dai ◽  
Li Lin ◽  
Huaifeng Wang ◽  
Haitao Hu
Keyword(s):  
Turbulence Intensity ◽  
Field Measurement ◽  
Three Dimensional ◽  
Wind Data ◽  
Statistical Characteristics ◽  
Gust Factor ◽  
Characteristics Analysis ◽  
Wind Characteristics ◽  
The Mean ◽  
The Relationship

The field measurement was conducted to observe the wind field data of West Pacific typhoon “Maria” in this research. With the application of ultrasonic anemometers installed in different heights (10 m, 80 m, 100 m) of the tower, the three dimensional wind speed data of typhoon “Maria” was acquired. In addition, vane-type anemometers were installed to validate the accuracy of the wind data from ultrasonic anemometers. Wind characteristics such as the mean wind profile, turbulence intensity, integral length scale, and wind spectrum are studied in detail using the collected wind data. The relationship between the gust factor and turbulence intensity was also studied and compared with the existing literature to demonstrate the characteristics of Maria. The statistical characteristics of the turbulence intensity and gust factor are presented. The corresponding conclusion remarks are expected to provide a useful reference for designing wind-resistant buildings and structures.

Some Relationship between Safety Factor of Earthquake Slope and Related Parameters

2011 ◽  
Vol 422 ◽  
pp. 688-692
Author(s):  
Xiao Hei He ◽  
Geng You Han ◽  
Rui Hua Xiao
Keyword(s):  
Numerical Simulation ◽  
Rock Mechanics ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Static Method ◽  
Acceleration Coefficient ◽  
The Wenchuan Earthquake ◽  
Stability Of Slope ◽  
The Stability ◽  
The Relationship

Abstract:Since the Wenchuan earthquake happened, the slope stability had been paid much more attention. The safety factor is an important parameter that can be used to evaluate the stability of slope. The pseudo-static method that based on limit equilibrium and the method of numerical simulation can calculate the safety factor accurately, but the velocity that gets the result is slow. If we can establish the relationship between safety factor and some other parameters, then we can calculate the safety factor by using the relationship more quickly. This paper establishes much relationship, such as the relationship between the rock mechanics parameters and the average danymic safety factor, the relationship between the rock mechanics parameters and the ratio of average danymic safety factor to static safety factor, the relationship between the rock mechanics parameters and the average earthquake acceleration coefficient, the relationship between the average earthquake acceleration coefficient and the ratio of average danymic safety factor to static safety factor, and the relationship between the earthquake acceleration coefficient and the ratio of danymic safety factor to static safety factor on the condition of different rock mass.

On the Friction Coefficient in the Numerical Simulation of Tidal Wave Propagation

2010 ◽  
Author(s):  
Z. Y. Song ◽  
C. Cheng ◽  
F. M. Xu ◽  
J. Kong
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Friction Factor ◽  
Tidal Wave ◽  
Computational Time ◽  
Numerical Dissipation ◽  
Courant Number ◽  
Time Step ◽  
Large Time Step ◽  
The Relationship

Based on the analytical solution of one-dimensional simplified equation of damping tidal wave and Heuristic stability analysis, the precision of numerical solution, computational time and the relationship between the numerical dissipation and the friction dissipation are discussed with different numerical schemes in this paper. The results show that (1) when Courant number is less than unity, the explicit solution of tidal wave propagation has higher precision and requires less computational time than the implicit one; (2) large time step is allowed in the implicit scheme in order to reduce the computational time, but the precision of the solution also reduce and the calculation precision should be guaranteed by reducing the friction factor: (3) the friction factor in the implicit solution is related to Courant number, presented as the determined friction factor is smaller than the natural value when Courant number is larger than unity, and their relationship formula is given from the theoretical analysis and the numerical experiments. These results have important application value for the numerical simulation of the tidal wave.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals Bioecology of Manggabai Fish (Glossogobius giuris) in Limboto Lake

2020 ◽  
Vol 4 (2) ◽  
pp. 89
Author(s):  
Dewi Nuryanti Fazrin ◽  
Hasim Hasim ◽  
Juliana Juliana
Keyword(s):  
Fishing Gear ◽  
Residential Areas ◽  
Chemical Parameters ◽  
Fish Traps ◽  
Physical And Chemical Parameters ◽  
Glossogobius Giuris ◽  
Net Cages ◽  
Physical And Chemical ◽  
Traditional Fishing ◽  
The Relationship

The purpose of this study was to determine the relationship between the length and weight of Manggabai fish (Glossogobius giuris) and to know the relationship between the presence of Manggabai fish (Glossogobius giuris) and water quality in Limboto Lake. This research was conducted in February 2019, located in the waters of Lake Limboto, Gorontalo Province. The method used in determining the location of sampling is Purposive Sampling. Fish sampling is determined by considering fishing locations, litoral areas, the presence of residential areas, agricultural and plantation areas, the existence of floating net cages and in the middle of the lake. The study was conducted at 20 observation stations using fish traps in the form of bamboo and used motorcycle tires that have been modified and become traditional fishing gear. The results showed that the physical and chemical parameters in Lake Limboto and showed temperature values ​​ranged from 29.77 to 31.630C, dissolved oxygen levels ranged from 2.1 to 5.48 ppm, pH ranged from 7.09 to 8.94, TDS ranging from 0.251 to 0.369, Nitrite Levels 0.04-0.08 ppm, Nitrate Levels 1.2-4.7 ppm, BOD ranges from 2.5-57 ppm and phosphate levels 0.1-1.14 ppm. The relationship between length and body weight of fish are allometric, where W = 0.8769 L10,023 and constant b (10,023)> 3.

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