wind pressure
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Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 405
Author(s):  
Filip Lisowski ◽  
Edward Lisowski

The article presents the results of computational fluid dynamics (CFD) analysis of the wind action on liquefied natural gas (LNG) ambient air vaporizers (AAVs). A study concerning AAV with a 6 × 6 tubes array is presented to demonstrate how the distribution of longitudinal finned tubes and wind direction affect the average load and wind pressure acting on the vaporizer structure. The main goal of the study is to estimate the wind load on the structure and wind pressure on individual tubes depending on the pitch of the tubes arrangement. The above parameters are crucial for the strength analysis of the vaporizer structure. The derived analysis results provide important data on the variation of pressure on individual tubes, wind velocity inside AVV structure and indicate a significant increase in the average wind load acting on the structure for a wind direction of 45 degrees compared to a perpendicular direction.


Author(s):  
Gun Gun Maulana ◽  
Aris Budiyarto ◽  
Ridwan

Each production requires a system monitoring, so efficiency that the desired and productivity can be achieved and monitored in real time. This system is needed in the type of press machine production which is mainly influenced by based production lead time. The monitoring process is one of the factors that influences the time of production and manufacturing. Conventionally, the system is monitoring carried out manually by the operator on a piece of paper. This method tends to create errors and quite a long time. This paper aims to overcome the problems that occur by creating a system that is able to record and monitor the machine automatically. The solution is made by utilizing a sensor limit switch, infrared, pressure transmitter and Wi-Fi network based on Web Interface that is connected to the Firebase real time database. Equipped with PID control using the Ziegler Nichols 1 method to stabilize wind pressure on the system. Monitoring devices can be accessed on PCs, laptops, smartphones, connected to the internet, equipped with user-level operators, management, or engineers so that they can be used easily. All production data for each press is collected in a database. The data will be processed by the system to produce a value OEE machine. All data will be displayed on the Web Interface in real-time. The system output is the actual production, value OEE and wind pressure control. The test results show the system is running well, with 2s delay time and data accuracy of ± 0.2%.


2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Zi-hou Yuan ◽  
Ming-xiang ◽  
Yi-chen

The hyperbolic thin-shell cooling tower is a typical wind-sensitive structure. The full-size measurement is the most direct and important way to study the distribution of wind pressure on the surface of the cooling tower. Due to the limitations of engineering conditions and meteorological conditions, the field measured data are relatively lacking, and the field test data of ribbed cooling towers are less. In order to analyze the wind pressure distribution on the surface of the cooling tower, we chose a ribbed cooling tower in Toksun County, Xinjiang, China, where there are strong winds all year round, and field measurements were carried out to understand the wind load characteristics of the tower under the perennial dominant wind direction and the maximum wind direction. It was found that the absolute value of the negative pressure on the leeward side was larger than that in the code and the fluctuating wind pressure coefficient fluctuates greatly when the field measured wind speed was greater than 10m/s (15 meters above the ground). For circular section cooling tower, the Reynolds number (Re) has great influence on wind pressure. With the increase of Re, the absolute value of the average negative pressure of the tail wind pressure coefficient increases, which should be paid attention to in design. The regression curves of the average wind pressure coefficients measured on site under several typical working conditions are given by using the least square method, and its form is consistent with the standard (but the coefficients are different). In addition, Fluent software was used to calculate the external wind pressure of the cooling tower, and the field measured results were compared with the Chinese code, German code and numerical calculation, and the results were consistent.


2021 ◽  
Vol 13 (24) ◽  
pp. 13815
Author(s):  
Hyok Chu Choi ◽  
Koochul Ji ◽  
Kyungrok Kwon ◽  
Jung Sik Kong

Standing Seam Metal Roofs (SSMRs) are widely used in the construction of industrial buildings, and their structural characteristics are rapidly being changed in order to improve the parameters of heat insulation and waterproofness. However, newly employed SSMRs did not account for a potential structural instability under strong winds by considering the multi-function of SSMRs. In this study, three different types of new SSMRs were chosen as specimens and were used in full-scale experiments, which were performed using the cyclic wind uplift method based on ASTM E1592 regulations. In contrast to a previous study in which the ultimate failure of the roof under wind pressure corresponded to seam line failure due to panel deflection, in this study, the experimental results show that seam separation was induced by a mid-clip rupture. It is verified that the behavior of the mid-clip plays a significant role in the overall performance of SSMRs under wind uplift loading. The objectives of this study were to (i) understand the structural performance and failure mode of new SSMRs under wind uplift pressure, as this condition is closest to reality, and to (ii) quantify the structural sustainability, which can be applied to risk-management practices through the established performance evaluation. It is expected that the present research results may provide future directions for improving the test standards, design guidelines, and risk-management practices.


Author(s):  
Dehai Luo

Abstract A linear Ekman model in the stratified atmospheric boundary layer (ABL) is proposed based on the steady state version of the linearized three-dimensional primitive equations with the inclusion of the vertical diffusivity. Due to the inclusion of the potential temperature equation and hydrostatic equation, pressure and potential temperature couple with wind in the proposed model, and thus are not arbitrarily specified variables as in previous studies on the baroclinicity in the Ekman model. The extended thermal wind balance equation and the Ekman potential vorticity equation are derived to describe the coupling. The two equations, along with the equation describing the constraint on potential temperature, are employed to derive the analytical solutions of the proposed Ekman model. Because potential temperature is not a specified variable but part of the solution, the derived analytical solutions have very different forms from those derived in previous studies. The differences illustrate the impact of the inclusion of the potential temperature equation and hydrostatic equation on wind, pressure and potential temperature in the proposed Ekman model. It is found that the computed wind profiles based on the proposed model can capture some important features of the observed wind profiles.


2021 ◽  
Vol 12 (2) ◽  
pp. 1083-1092
Author(s):  
Guangjiu Qin ◽  
Shuohua Zhang ◽  
Hao Jing

Abstract. At present, the wind-induced vibration effects of super-high-rise buildings caused by wind loads can no longer be ignored. The wind-induced vibration effect of super-high-rise buildings will inevitably cause the vibration of ultra-high-speed elevators. However, for the study of the vibration characteristics of ultra-high-speed elevators, the wind-induced vibration effect of the ultra-high-speed elevator is often ignored. Based on Bernoulli–Euler theory, the forced vibration differential equation of elevator guide rail was established, and the vibration equation of elevator guide shoe and car was established by using the Darren Bell principle. The coupled vibration model of the guide rail, guide shoes, and car can be obtained through the relationship of force and relative displacement among these components. Based on the model, the effects of wind pressure and building height on the horizontal vibration of the ultra-high-speed guideway and passenger comfort were analyzed. The results showed that the influence of the wind load on the vibration of ultra-high-speed elevator can no longer be disregarded, and the maximum horizontal vibration acceleration of the guide rail is positively correlated with the height of building. The vibration acceleration of the same height rail increases with the increase in wind pressure. The vibration dose values (VDVs) increase with the increase in wind pressure and building height, respectively.


2021 ◽  
Author(s):  
Xiang Chen ◽  
Xiang Duan

In the architectural planning and design, the commonly used architectural layout forms are determinant, diagonal, etc. Because of its centralized and symmetrical layout form, determinant architecture has been widely used in urban architectural design. Due to the high density of multi span buildings, the ventilation effect is not good, so this paper mainly studies the influence of multi span building layout on the wind field of urban ordinary residence. In order to optimize the wind environment of the building, a 7-story residential area was modeled and calculated by CFD. Through the analysis of wind field characteristics at different building heights, the results show that the total wind speed in Z direction of the building is the smallest, about 3.354 m/s; At the same time, the overall wind pressure values are within 5Pa of the standard wind pressure difference, but we still need to pay close attention to the possible environmental impact at the outlet of the determinant residence.


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