scholarly journals Experimental investigation of the aerodynamics of a large industrial building with parapet

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Aly Mousaad Aly ◽  
Matthew Thomas ◽  
Hamzeh Gol-Zaroudi
Keyword(s):  
Flow Pattern ◽  
Separation Bubble ◽  
Industrial Building ◽  
Pressure Coefficients ◽  
Industrial Buildings ◽  
Straight Line ◽  
Mean Pressure ◽  
The Mean ◽  
Wind Pressures ◽  
Peak Pressures

AbstractThe aerodynamic performance of a roof depends significantly on its shape and size, among other factors. For instance, large roofs of industrial low-rise buildings may behave differently compared to those of residential homes. The main objective of this study is to experimentally investigate how perimeter solid parapets can alter the flow pattern around a low-rise building with a large aspect ratio of width/height of about 7.6, the case of industrial buildings/shopping centers. Solid parapets of varied sizes are added to the roof and tested in an open-jet simulator in a comparative study to understand their impact on roof pressure coefficients. Roof pressures were measured in the laboratory for cases with and without parapets under different wind direction angles (representative of straight-line winds under open terrain conditions). The results show that using a parapet can alter wind pressures on large roofs. Parapets can modify the flow pattern around buildings and change the mean and peak pressures. The mean pressure pattern shows a reduction in the length of the separation bubble due to the parapet. The parapet of 14% of the building’s roof height is the most efficient at reducing mean and peak pressures compared to other parapet heights.

Reattachment of a Two-Dimensional, Incompressible Jet to an Adjacent Flat Plate

1960 ◽  
Vol 11 (3) ◽  
pp. 201-232 ◽  
Author(s):  
C. Bourque ◽  
B. G. Newman
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Separation Bubble ◽  
Volume Flow ◽  
Turbulent Jet ◽  
Two Dimensional ◽  
General Investigation ◽  
Mean Pressure ◽  
The Mean ◽  
Coandǎ Effect

SummaryAs part of a general investigation into Coanda effect, a study has been made of the reattachment of a two-dimensional, incompressible, turbulent jet to an adjacent, inclined, flat plate. The jet separates from the boundaries at the slot lips and reattaches to the plate downstream, a phenomenon which is associated with the lowering of the pressure between the jet and the plate accompanying the entrainment of fluid there. It is found that the flow becomes independent of both the length of the plate and the Reynolds number when these parameters are sufficiently large: the flow, scaled with respect to the width of the slot, is then uniquely determined by the plate inclination. Two approximate theories are developed for the mean pressure within the separation bubble, the position of reattachment and the increase in volume flow from the slot: the agreement with experiment is fairly satisfactory. These theories are a development of Dodds's analysis for the reattachment of a jet to a plate offset from, and parallel to, the axis of the slot and, for the purpose of comparison, a limited study is also made of this flow.

Experimental Investigation of Wind Loads on Fish-Shaped Roof Structures

2013 ◽  
Vol 639-640 ◽  
pp. 434-443
Author(s):  
Ming Liang Zhang ◽  
Qiu Sheng Li
Keyword(s):  
Experimental Investigation ◽  
Lower Surface ◽  
Shape Coefficient ◽  
Pressure Coefficients ◽  
Minimum Pressure ◽  
Mean Pressure ◽  
Wind Actions ◽  
Rigid Model ◽  
The Mean ◽  
Two Sides

Wind tunnel tests of 1:100 rigid model of fish-shaped roof structures were carried out. The mean, fluctuating (RMS) and peak pressure coefficients, the local shape coefficient distributions on fish-shaped roofs were presented and discussed. It was found that negative pressures (suctions) occurred on the most areas on the roofs, and high negative pressure coefficients occurred on the eaves and cantilevered roof parts. When wind flows blew along the corridors under the roofs, the flows enhanced suctions on the surfaces of the roofs, and the suctions on the lower surface were greater than those on the upper surfaces, positive pressures occurred on that area after superposition of wind actions on the two sides. The roof eaves and regions above the corridors experienced the worst RMS pressure coefficients and the worst minimum pressure coefficients. The distribution characteristics of the worst RMS and minimum pressure coefficients were found to be quite similar to those of the mean pressure coefficients. The results obtained from the experimental investigation are expected to be useful in the wind-resistant design of complex roof structures in typhoon-prone regions.

WIND PRESSURE DISTRIBUTION ON NORTH-LIGHT INDUSTRIAL BUILDING ROOF STUDY

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Astha Verma ◽  
Ashok Kumar Ahuja
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Wind Pressure ◽  
Closed Circuit ◽  
Industrial Building ◽  
Building Roof ◽  
Pressure Coefficients ◽  
Wind Pressures

Present paper describes details of the experimental study carried out on the models of industrial building with north-light roof in order to generate the information about wind pressure distribution on it. The models are tested in a closed circuit boundary layer wind tunnel to measure values of wind pressures on roof surface. Four cases namely one, two, three and four spans are considered. The side of Perspex sheet model in case of multi-span study places plywood models. Wind is made to hit the models at 13 wind incidence angles from 0° to 180° at an interval of 15°. Values of mean wind pressure coefficients are evaluated from the measured values of wind pressures and contours are plotted.

Effects of the Playing Surface on Plantar Pressures During the First Serve in Tennis

2010 ◽  
Vol 5 (3) ◽  
pp. 384-393 ◽  
Author(s):  
O. Girard ◽  
J.-P. Micallef ◽  
G.P. Millet
Keyword(s):  
Contact Area ◽  
Significant Interaction ◽  
Tennis Players ◽  
Relative Load ◽  
Plantar Pressures ◽  
Loading Patterns ◽  
Force Peak ◽  
Mean Pressure ◽  
The Mean ◽  
Peak Pressures

Purpose:This study aimed at examining the influence of different playing surfaces on in-shoe loading patterns in each foot (back and front) separately during the first serve in tennis.Methods:Ten competitive tennis players completed randomly five frst (ie, fat) serves on two different playing surfaces: clay vs GreenSet. Maximum and mean force, peak and mean pressure, mean area, contact area and relative load were recorded by Pedar insoles divided into 9 areas for analysis.Results:Mean pressure was significantly lower (123 ± 30 vs 98 ± 26 kPa; -18.5%; P < .05) on clay than on GreenSet when examining the entire back foot. GreenSet induced higher mean pressures under the medial forefoot, lateral forefoot and hallux of the back foot (+9.9%, +3.5% and +15.9%, respectively; both P < .01) in conjunction with a trend toward higher maximal forces in the back hallux (+15.1%, P = .08). Peak pressures recorded under the central and lateral forefoot (+21.8% and +25.1%; P < .05) of the front foot but also the mean area values measured on the back medial and lateral midfoot were higher (P < .05) on clay. No significant interaction between foot region and playing surface on relative load was found.Conclusions:It is suggested that in-shoe loading parameters characterizing the first serve in tennis are adjusted according to the ground type surface. A lesser asymmetry in peak (P < .01) and mean (P < .001) pressures between the two feet was found on clay, suggesting a greater need for stability on this surface.

The effects of turbulence on a separated and reattaching flow

1987 ◽  
Vol 178 ◽  
pp. 477-490 ◽  
Author(s):  
Yasuharu Nakamura ◽  
Shigehira Ozono
Keyword(s):  
Pressure Distribution ◽  
Turbulence Intensity ◽  
Free Stream ◽  
Separation Bubble ◽  
Plate Thickness ◽  
Turbulence Scale ◽  
Free Stream Turbulence ◽  
Mean Pressure ◽  
Scale Ratio ◽  
The Mean

The effect of free-stream turbulence on the mean pressure distribution along the separation bubble formed on a flat plate with rectangular leading-edge geometry is investigated experimentally in a wind tunnel using turbulence-producing grids. Emphasis is placed on finding the effect of turbulence scale. The ratio of turbulence scale to plate thickness investigated was about 0.5 to 24 for two values of turbulence intensity of about 7 and 11%. The Reynolds number based on plate thickness was approximately (1.4–4.2) × 104.It is found that the main effect of free-stream turbulence is to shorten the separation bubble. It is progressively shortened with increasing turbulence intensity. The mean pressure distribution along the shortened separation bubble is insensitive to changing turbulence scale up to a scale ratio of about 2. With further increase in the scale ratio it asymptotes towards the smooth-flow distribution. There is no trace of interaction between turbulence and vortex shedding (the impinging-shear-layer instability) in the mean pressure distribution.

Effects of Geometrical Factors on Wind Pressure Characteristics of Cylindrical Roofs with Wind Tunnel Tests

2013 ◽  
Vol 351-352 ◽  
pp. 284-289 ◽  
Author(s):  
Bo Chen ◽  
Qing Shan Yang
Keyword(s):  
Wind Tunnel ◽  
Probability Distributions ◽  
Wind Pressure ◽  
Wind Tunnel Tests ◽  
Pressure Coefficients ◽  
High Rise ◽  
Mean Pressure ◽  
The Mean ◽  
Geometrical Factors ◽  
Pressure Characteristics

With wind tunnel tests, simultaneous pressure measurements are made on 4 cylindrical roof models with different rise-span ratios and roof inclinations. Effects of these geometrical factors on wind pressure characteristics of the roofs are investigated, including mean pressure coefficients, RMS pressure coefficients, skewness, kurtosis, and probability distributions of wind pressure. Results show that the mean vertical wind force coefficient of high rise-span ratio roof is larger than that of the low rise-span ration roof; the mean pressure coefficient distribution of the low rise-span ratio roof is similar to that of RMS pressure coefficients and the skewness (or the kurtosis); the vortex center line occurs at the windward edge for the low rise-span ratio roof with inclination 0°, which occurs at the roof apex for the high rise-span ratio roof. The roof inclination has more effects on the low rise-span ratio roof, the vortex moves from the windward edge to the apex for the roof with inclination 7.2°when the wind flows from the low eave to the high eave. The distribution of the skewness is strongly correlative to that of the kurtosis. The probability distributions of the roof edges and corners deviate obviously from the Guass distribution. If this point is ignored, the peak suction pressure will be underestimated.

Wind Loading on Catenary Domes

2019 ◽  
Author(s):  
Richard M. van Gool ◽  
Ryan A. Bradley ◽  
Mitchell Gohnert
Keyword(s):  
Pressure Coefficient ◽  
Wind Loading ◽  
Pressure Coefficients ◽  
Hemispherical Dome ◽  
Circular Profile ◽  
Mean Pressure ◽  
Efficient Alternative ◽  
Base Radius ◽  
The Mean ◽  
Layer Flow

<p>Catenary domes are a less conventional, but structurally efficient, alternative to traditional circular-profile domes. Unlike the more common circular forms, there is a dearth of wind loading information for catenary structures. This paper aims to provide some insight in this regard. A series of wind tunnel tests were undertaken to investigate the effects of geometry and Reynolds number on the mean pressure coefficient distributions over catenary domes in a turbulent boundary layer flow. A hemispherical dome was also assessed, and the results compared with that for the catenary shapes. These parameters were evaluated to elucidate their influence on the loading on these structures. Only the results relating to mean pressure coefficients are reported in this paper. An important finding was that the height to base radius (H/R) of the catenary dome had a substantial influence on the mean pressure coefficient distributions over the structure. Finally, the results of the investigation and their implications on the design of catenary domes are discussed. This may be of value to designers because at present no wind loading information exists for catenary domes</p><p>– at least to the author’s knowledge.</p>

Functional and aesthetic transformation of industrial into housing spaces

2019 ◽  
Vol 17 (4) ◽  
pp. 401-416 ◽  
Author(s):  
Ana Stanojevic ◽  
Aleksandar Kekovic
Keyword(s):  
Urban Areas ◽  
Physical Structure ◽  
Industrial Building ◽  
Single Family ◽  
Industrial Heritage ◽  
Industrial Buildings ◽  
Industrial Architecture ◽  
Research Goal ◽  
The Aesthetic ◽  
Xix Century

Buildings preservation by the conversion of their function has become a domain of interest in the field of industrial heritage. Due to the need to expand existing housing capacities in urban areas, a large number of industrial buildings are nowadays converted into multi-family and single-family housing. The paper deals with the analysis of the functional and aesthetic internal transformation of industrial into housing spaces. The research goal is to determine the principles of conceptualization of housing functional plan within the framework of the original physical structure of the industrial building, at the architectonic composition level and housing unit (dwelling) level. Besides, the paper aims to check the existence of common patterns of the aesthetic transformation of converted spaces, examined through three epochs of the development of industrial architecture: the second half of the XIX century, the first half of the XX century and the post-WWII period.

scholarly journals Weighted statistical binary patterns for facial feature representation

2021 ◽  
Author(s):  
Hung Phuoc Truong ◽  
Thanh Phuong Nguyen ◽  
Yong-Guk Kim
Keyword(s):  
Comprehensive Evaluation ◽  
Facial Feature ◽  
Input Image ◽  
Feature Representation ◽  
Illumination Variation ◽  
Straight Line ◽  
Mean And Variance ◽  
The Mean ◽  
Face Datasets ◽  
Degraded Images

AbstractWe present a novel framework for efficient and robust facial feature representation based upon Local Binary Pattern (LBP), called Weighted Statistical Binary Pattern, wherein the descriptors utilize the straight-line topology along with different directions. The input image is initially divided into mean and variance moments. A new variance moment, which contains distinctive facial features, is prepared by extracting root k-th. Then, when Sign and Magnitude components along four different directions using the mean moment are constructed, a weighting approach according to the new variance is applied to each component. Finally, the weighted histograms of Sign and Magnitude components are concatenated to build a novel histogram of Complementary LBP along with different directions. A comprehensive evaluation using six public face datasets suggests that the present framework outperforms the state-of-the-art methods and achieves 98.51% for ORL, 98.72% for YALE, 98.83% for Caltech, 99.52% for AR, 94.78% for FERET, and 99.07% for KDEF in terms of accuracy, respectively. The influence of color spaces and the issue of degraded images are also analyzed with our descriptors. Such a result with theoretical underpinning confirms that our descriptors are robust against noise, illumination variation, diverse facial expressions, and head poses.

scholarly journals Probability Characteristics, Area Reduction, and Wind Directionality Effects of Extreme Pressure Coefficients of High-Rise Buildings

2021 ◽  
Vol 11 (15) ◽  
pp. 7121
Author(s):  
Shouke Li ◽  
Feipeng Xiao ◽  
Yunfeng Zou ◽  
Shouying Li ◽  
Shucheng Yang ◽  
...  
Keyword(s):  
Probability Distribution ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Extreme Pressure ◽  
Distribution Law ◽  
Distribution Fitting ◽  
Pressure Coefficients ◽  
High Rise ◽  
Area Reduction ◽  
The Mean

Wind tunnel tests are carried out for the Commonwealth Advisory Aeronautical Research Council (CAARC) high-rise building with a scale of 1:400 in exposure categories D. The distribution law of extreme pressure coefficients under different conditions is studied. Probability distribution fitting is performed on the measured area-averaged extreme pressure coefficients. The general extreme value (GEV) distribution is preferred for probability distribution fitting of extreme pressure coefficients. From the comparison between the area-averaged coefficients and the value from GB50009-2012, it is indicated that the wind load coefficients from GB50009-2012 may be non-conservative for the CAARC building. The area reduction effect on the extreme wind pressure is smaller than that on the mean wind pressure from the code. The recommended formula of the area reduction factor for the extreme pressure coefficient is proposed in this study. It is found that the mean and the coefficient of variation (COV) for the directionality factors are 0.85 and 0.04, respectively, when the orientation of the building is given. If the uniform distribution is given for the building’s orientation, the mean value of the directionality factors is 0.88, which is close to the directionality factor of 0.90 given in the Chinese specifications.

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