LES study of wind pressure and flow characteristics of flat-roof-mounted solar arrays

2020 ◽  
Vol 198 ◽  
pp. 104096 ◽  
Author(s):  
Jingxue Wang ◽  
Pham Van Phuc ◽  
Qingshan Yang ◽  
Yukio Tamura
Keyword(s):  
Flow Characteristics ◽  
Wind Pressure ◽  
Solar Arrays ◽  
Flat Roof

Comparisons of design wind pressures on roof-mounted solar arrays between wind tunnel tests and codes and standards

2020 ◽  
pp. 136943322096527
Author(s):  
Jingxue Wang ◽  
Qingshan Yang ◽  
Yi Hui
Keyword(s):  
Wind Tunnel ◽  
Experimental Results ◽  
Solar Panels ◽  
Wind Tunnel Tests ◽  
Pressure Equalization ◽  
Solar Arrays ◽  
Side Ratio ◽  
Design Values ◽  
Wind Pressures ◽  
Flat Roof

The current codes and standards concerning wind loads on roof-mounted solar panels are discussed and summarized. Wind pressures on flat- and slope-roof-mounted solar arrays obtained from wind tunnel tests are compared with the recommended design values in ASCE 7-16 and JIS C 8955: 2017. Different parameters, including building side ratio, aspect ratio and parapet height, are examined. Results show that the largest wind pressures on flat-roof-mounted solar panels of all zones in ASCE 7-16 tend to be 10% to 26% smaller than the experimental results when normalized tributary area An is larger than 103. Uplift wind forces on flat-roof-mounted solar panels in downstream regions obtained from experiments can be larger than the recommended values in JIS C 8955: 2017 for adverse wind, but downward force coefficients are basically smaller than those in JIS C 8955: 2017 for fair wind. 40% to 60% increase on the pressure equalization factor for slope-roof-mounted solar panels is suggested for the potential refinement of ASCE 7-16 based on this study. Meanwhile, proposed pressures of slope-roof-mounted solar panels in JIS C 8955: 2017 might be too conservative according of experimental results.

scholarly journals Study of Pressure Distribution on an Irregular Octagonal Plan Oval-Shape Building Using CFD

2021 ◽  
Vol 7 (10) ◽  
pp. 1787-1805
Author(s):  
Arun Kumar ◽  
Ritu Raj
Keyword(s):  
Pressure Distribution ◽  
Natural Ventilation ◽  
Open Space ◽  
Flow Characteristics ◽  
Wind Pressure ◽  
Wind Flow ◽  
Steady State Flow ◽  
Building Model ◽  
Ansys Cfx ◽  
Oval Shape

This paper aims to study the wind flow characteristics and to analyze the wind pressure distribution on the surfaces around an irregular octagonal plan shape building model. There is a central open space in plan to provide more surface area around the building for natural ventilation. Plan area of the building is 300 m2(excluding the open space) and height is 50 m. Steady state flow of wind with 5% turbulence (moderate turbulence) under atmospheric boundary layer has been taken in the study. Numerical simulation with standard k-e model using ANSYS (CFX) software has been used for the purpose. Flow characteristics has been studied in terms of flow separation, reattachment of flow, creation of wakes and vortices. The surface pressure generated around the model has been studied in terms of coefficient of pressure. The model is symmetrical about both the axes in plan. Hence, study for different wind angle of attacks from 0° to 90° @ 30° interval has been conducted. The flow characteristics and unusual or critical coefficient of pressure on surfaces of the model observed have been discussed. Doi: 10.28991/cej-2021-03091760 Full Text: PDF

Analysis of Internal Flow Field for Centrifugal Fan in Series

2012 ◽  
Vol 233 ◽  
pp. 96-99
Author(s):  
Ya Jun Fan ◽  
Zhang Xu ◽  
Ding Wensi
Keyword(s):  
Velocity Distribution ◽  
Total Pressure ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Wind Pressure ◽  
Meridian Plane ◽  
Centrifugal Fan ◽  
Fan Performance ◽  
In Series ◽  
The Impact

Centrifugal fan in series with high wind pressure is the key facility of pneumatic transport equipment. To consider the impact of changed conditions on performance of centrifugal fan, internal flow of three-stage centrifugal fan at rated speed in different total pressure conditions is analyzed by CFD software FLUENT6.3 in this paper. Flow characteristics are obtained and the differences of total pressure and velocity distribution in each impeller are analyzed under different conditions, velocity distribution on the meridian plane and section of wind guide plates are compared. Finally, curves of P-Q and P-η at 4600 r/min are forecasted through the analysis of the data, which provide references for reducing impact that condition alteration on fan performance and improving the efficiency of the fan.

Simulation Study on the Wind Pressure of Village Flat Roof with Parapet Based on Different Wind Angles

2014 ◽  
Vol 638-640 ◽  
pp. 228-232 ◽  
Author(s):  
Jun Liu ◽  
Yuan Quan Yang ◽  
Yan Lei Sun ◽  
Bin He
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Pressure Fluctuation ◽  
Field Measurement ◽  
Pressure Coefficient ◽  
Air Pressure ◽  
Wind Pressure ◽  
Simulation Technology ◽  
Wind Tunnel Tests ◽  
Flat Roof

The main research methods to predict and research wind loads on buildings at home and abroad include wind tunnel tests, field measurement and numerical simulation. However, the wind tunnel tests and field measurement require big funds, long cycle and complicated measurement. Moreover, numerical simulation technology is quite mature. In this paper, based on fluid dynamics software CFD and criteria Reynolds k-ε turbulence model, wind field of the village flat roof with parapet is studied using the numerical simulation technology. Furthermore, the wind pressure data in different wind angles are processed and analyzed. The results show that wind angle has a significant impact on the wind pressure and its distribution. When the wind angle is 0 °, the air pressure-fluctuation in each node of the roof is small, and the pressure coefficient is steady between -1.50 and -2.00. When the wind angle is 45 °, the air pressure fluctuation in each node of the roof is large, and the pressure coefficient fluctuates between -0.8 and -3.0. When the wind angle is 90 °, the wind pressure-fluctuation in each node of the roof is equal to the fluctuation between 0 ° and 45 °wind direction angle, and the wind pressure coefficient fluctuates between -0.7 and -1.7. When incoming flow is along the asymmetric axis, the wind pressure-fluctuation is large, and the wind pressure is greater than that in the large negative pressure zone which is along the symmetry axis, which can bring serious damage on the roof.

scholarly journals On the Use of the Cubic Translation to Model Bimodal Wind Pressures

2019 ◽  
Vol 15 (2) ◽  
pp. 20-32
Author(s):  
François Rigo ◽  
Thomas Andrianne ◽  
Vincent Denoël
Keyword(s):  
Bimodal Distribution ◽  
Wind Pressure ◽  
Wind Engineering ◽  
Pressure Data ◽  
Direct Evaluation ◽  
Translation Model ◽  
Background Turbulence ◽  
Wind Pressures ◽  
Non Gaussian ◽  
Flat Roof

Abstract The cubic translation model is a well know tool in wind engineering, which provides a mathematical description of a non-Gaussian pressure as a cubic transformation of a Gaussian process. This simple model is widely used in practice since it offers a direct evaluation of the peak factors as a function of the statistics of the wind pressure data. This transformation is rather versatile but limited to processes which are said to be in the monotonic region. For processes falling outside this domain, this paper describes an alternative which is based on the physics of the wind flow. First, it is shown, with a classical example of a flow involving corner vortices on a flat roof, that the pressure data which does not meet the monotonic criterion is in fact associated with a bimodal distribution. Then, the proposed approach is to decompose this data into the two governing modes (slow background turbulence and fast corner vortices) and apply the usual translation model to each of them.

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