scholarly journals Wind-tunnel estimation of mean and turbulent wind speeds within canopy layer for urban campus

Urban Climate ◽  
2022 ◽  
Vol 41 ◽  
pp. 101064
Author(s):  
Yin Mun H'ng ◽  
Naoki Ikegaya ◽  
Sheikh Ahmad Zaki ◽  
Aya Hagishima ◽  
Ahmad Faiz Mohammad
Keyword(s):  
Wind Tunnel ◽  
Canopy Layer ◽  
Turbulent Wind ◽  
Wind Speeds ◽  
Urban Campus

The Effect of Cross-Winds on Trains

1981 ◽  
Vol 103 (1) ◽  
pp. 170-178 ◽  
Author(s):  
R. K. Cooper
Keyword(s):  
Wind Tunnel ◽  
Model Experiment ◽  
High Speed ◽  
Wind Tunnel Tests ◽  
Turbulent Wind ◽  
Wind Speeds ◽  
High Speed Trains ◽  
Low Mass

Low mass, high speed trains may be in danger of being overturned by strong crosswinds. This paper examines the aerodynamic data required to estimate overturning wind speeds. The results of wind tunnel tests and a moving model experiment, including the effect of the turbulent wind, are described.

scholarly journals Influence of the near standing hall for wind flowing around group of circular cylinders

2020 ◽  
Vol 310 ◽  
pp. 00013 ◽  
Author(s):  
Ivana Veghova ◽  
Olga Hubova
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Circular Cylinders ◽  
Wind Flow ◽  
Force Coefficient ◽  
Turbulent Wind ◽  
Wind Speeds ◽  
Wind Pressure Coefficient

This article deals with experimental investigation of air flow around in – line standing circular cylinders and influence of nearby standing hall on external wind pressure distribution. The wind pressure distribution on the structures is an important parameter in terms of wind load calculation. For vertical circular cylinders in a row arrangement only wind force coefficient is possible find in Eurocode. 1991-1-4. External wind pressure coefficient depends on wind direction and the ratio of distance and diameter b. Influence of nearby standing structure is not possible find in Eurocode. The series of parametric wind tunnel studies was carried out in Boundary Layer Wind Tunnel (BLWT) STU to investigate the external wind pressure coefficient in turbulent wind flow. Experimental measurements were performed in BLWT for 2 reference wind speeds, which fulfilled flow similarity of prototype and model. We have compared the results of free in - line standing 3 circular cylinder and influence of hall on distribution of wind pressure at 3 height levels in turbulent wind flow and these results were compared with values in EN 1991-1-4.

Study on the Relation Between Side Ratios of Rectangular Cross Sections and Secondary Vortices at Trailing Edge in Motion-Induced Vortex Excitation

2017 ◽  
Author(s):  
Kazutoshi Matsuda ◽  
Kusuo Kato ◽  
Kouki Arise ◽  
Hajime Ishii
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Cross Sections ◽  
Leading Edge ◽  
Trailing Edge ◽  
Wind Speeds ◽  
Smoke Flow ◽  
Flow Visualizations ◽  
Institute Of Technology ◽  
Secondary Vortices

According to the results of conventional wind tunnel tests on rectangular cross sections with side ratios of B/D = 2–8 (B: along-wind length (m), D: cross-wind length (m)), motion-induced vortex excitation was confirmed. The generation of motion-induced vortex excitation is considered to be caused by the unification of separated vortices from the leading edge and secondary vortices at the trailing edge [1]. Spring-supported test for B/D = 1.18 was conducted in a closed circuit wind tunnel (cross section: 1.8 m high×0.9 m wide) at Kyushu Institute of Technology. Vibrations were confirmed in the neighborhoods of reduced wind speeds Vr = V/fD = 2 and Vr = 8 (V: wind speed (m/s), f: natural frequency (Hz)). Because the reduced wind speed in motion-induced vortex excitation is calculated as Vr = 1.67×B/D = 1.67×1.18 = 2.0 [1], vibrations around Vr = 2 were considered to be motion-induced vortex excitation. According to the smoke flow visualization result for B/D = 1.18 which was carried out by the authors, no secondary vortices at the trailing edge were formed, although separated vortices from the leading edge were formed at the time of oscillation at the onset wind speed of motion-induced vortex excitation, where aerodynamic vibrations considered to be motion-induced vortex excitation were confirmed. It was suggested that motion-induced vortex excitation might possibly occur in the range of low wind speeds, even in the case of side ratios where secondary vortices at trailing edge were not confirmed. In this study, smoke flow visualizations were performed for ratios of B/D = 0.5–2.0 in order to find out the relation between side ratios of rectangular cross sections and secondary vortices at trailing edge in motion-induced vortex excitation. The smoke flow visualizations around the model during oscillating condition were conducted in a small-sized wind tunnel at Kyushu Institute of Technology. Experimental Reynolds number was Re = VD/v = 1.6×103. For the forced-oscillating amplitude η, the non-dimensional double amplitudes were set as 2η/D = 0.02–0.15. Spring-supported tests were also carried out in order to obtain the response characteristics of the models.

Wind Tunnel Model Study of the Hot Exhaust Plume From the Compressor Research Facility at Wright-Patterson Air Force Base, OH

1979 ◽  
Author(s):  
G. R. Ludwig
Keyword(s):  
Wind Tunnel ◽  
Air Force ◽  
Research Facility ◽  
Wind Tunnel Model ◽  
Wind Speeds ◽  
Model Study ◽  
Tunnel Model ◽  
Concentration Measurements ◽  
Building Ventilation ◽  
Air Force Base

This paper presents the results of a wind tunnel model study to determine temperatures at various locations generated by the hot exhaust air from the Compressor Research Facility [CRF] which is being built at Wright-Patterson Air Force Base, Ohio. The study was designed to provide data at the inlet to the CRF and at other nearby locations where pedestrians, building ventilation systems, and vegetation might be affected. The test program, which was conducted in the Calspan Atmospheric Simulation Facility, included flow visualization studies and quantitative concentration measurements of a tracer gas from which full-scale temperature could be calculated. The concentration measurements were performed for a number of wind speeds at each of twelve different wind directions. Two exhaust flows and two exhaust stack configurations were studied.

An overview of experiments on the dynamic sensitivity of MAVs to turbulence

2010 ◽  
Vol 114 (1158) ◽  
pp. 485-492 ◽  
Author(s):  
A. Watkins ◽  
M. Thompson ◽  
M. Shortis ◽  
R. Segal ◽  
M. Abdulrahim ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Micro Air Vehicles ◽  
Rating System ◽  
Flight Tests ◽  
Wind Environment ◽  
Turbulent Wind ◽  
High Turbulence ◽  
Per Se ◽  
Rotary Wing ◽  
Large Wind

Abstract Aspects of the turbulent wind environment Micro Air Vehicles (MAVs) experience when flying outdoors were replicated in a large wind tunnel. An overview of the facility, instrumentation and initial flight tests is given. Piloting inputs and aircraft accelerations were recorded on fixed and rotary wing MAVs and for some tests, measurements of the approach flow (u,v,w sampled at 1,250Hz at four laterally disposed upstream locations) were made. The piloting aim was to hold straight and level flight in the 12m wide × 4m high × ~50m long test section, while flying in a range of turbulent conditions. The Cooper-Harper rating system showed that a rotary craft was less sensitive to the effects of turbulence compared to the fixed wing craft and that while the fixed wing aircraft was relatively easy to fly in smooth air, it became extremely difficult to fly under high turbulence conditions. The rotary craft, while more difficult to fly per. se., did not become significantly harder to fly in relatively high turbulence levels. However the rotary craft had a higher mass and MOI than the fixed wing craft and further work is planned to understand the effects of these differences.

Effect of Nozzle Angleson Spray Losses Reduction

2014 ◽  
Vol 564 ◽  
pp. 216-221
Author(s):  
Nasir S. Hassen ◽  
Nor Azwadi Che Sidik ◽  
Jamaluddin Md Sheriff
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Mean Value ◽  
The Other ◽  
Spray Drift ◽  
Spray Application ◽  
Application Process ◽  
Nozzle Height ◽  
Wind Speeds ◽  
Flat Fan Nozzle

Spray losses are the most important problem that is faced in the spray application process as result of spray drift to non target areas by the action of air flow.This paper investigated the spray drift for banding applicationusing even flat-fan nozzle TPEunder wind tunnel conditions.In addition, this paper also examined the effect of different spray fan angles 65°, 80° and 95° on spray drift particularly where there is need to make the nozzle operate at the optimum heights above the ground or plant level.In addition, three cross wind speeds 1, 2 and 3m/swere produced to determine the effect of wind speed on total spray drift.According to the results from this study, the nozzle anglehas a significant effect on the total spray drift. The nozzle angle 65° gave the highest drift reduction compared to the other nozzle angles. The maximum driftfor all nozzles was found at nozzle height of 60 cm. The minimum mean value of the drift was found at wind speed of 1 m/s. This study supports the use of nozzle angles of less than 95° on heights more than 0.5m and on wind speeds more than 1m/s as a means for minimizing spray drift.

scholarly journals Investigation of the Superposition Effect of Oil Vapor Leakage and Diffusion from External Floating-Roof Tanks Using CFD Numerical Simulations and Wind-Tunnel Experiments

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 299
Author(s):  
Jie Fang ◽  
Weiqiu Huang ◽  
Fengyu Huang ◽  
Lipei Fu ◽  
Gao Zhang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Simulation Method ◽  
Vapor Concentration ◽  
Monitoring And Control ◽  
Wind Tunnel Experiments ◽  
Ambient Wind ◽  
Wind Speeds ◽  
High Concentrations ◽  
And Control

Based on computational fluid dynamics (CFD) and Realizable k-ε turbulence model, we established a numerical simulation method for wind and vapor-concentration fields of various external floating-roof tanks (EFRTs) (single, two, and four) and verified its feasibility using wind-tunnel experiments. Subsequently, we analysed superposition effects of wind speed and concentration fields for different types of EFRTs. The results show that high concentrations of vapor are found near the rim gap of the floating deck and above the floating deck surface. At different ambient wind speeds, interference between tanks is different. When the ambient wind speed is greater than 2 m/s, vapor concentration in leeward area of the rear tank is greater than that between two tanks, which makes it easy to reach explosion limit. It is suggested that more monitoring should be conducted near the bottom area of the rear tank and upper area on the left of the floating deck. Superposition in a downwind direction from the EFRTs becomes more obvious with an increase in the number of EFRTs; vapor superposition occurs behind two leeward tanks after leakage from four large EFRTs. Considering safety, environmental protection, and personnel health, appropriate measures should be taken at these positions for timely monitoring, and control.

scholarly journals Potential of dust emission resources using small wind tunnel and GIS: case study of Bakhtegan playa, Iran

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Siroos Karimzadeh ◽  
Mohammad Mehdi Taghizadeh
Keyword(s):  
Wind Tunnel ◽  
Present Model ◽  
Low Cost ◽  
Dust Emission ◽  
High Potential ◽  
Wind Speeds ◽  
Desert Areas ◽  
Medium Potential

Abstract Determination of the high potential of dust emission is a requisite affair in the management of dusts emission and as well as avoiding its risks. Wind tunnel is among the most important approaches in the study of areas having high potential in emitting dusts. Extensive dried playas and desert areas require the making of low-cost, simple, and car-portable tunnels capable of presenting comparable data of various areas even supposing not having enough precision in the model of real wind motion. In this study, we first engaged in making a car-portable tunnel with a primarily semicircle section of 38 cm height, 50 cm diameter, and 110 cm length. A fan and key appliance with the ability to change speed were used along with a simple transformer launched with car battery. Then, concentration of the pm10 dusts was measured in the various wind speeds of 1, 2.5, 4, 5.5, and 7 m/s by the help of anemometer and digital equipments. The study of Bakhtegan playa was done, as the methodology of handling with this tunnel, in 35 positions, and zoning of the results was performed via ArcGIS software. Depending on the destructibility of the shell by wind, the areas under study were categorized as low potential (34%), medium potential (37%), and high potential (29%) in emitting dusts. The results of zoning spotted the high-potential areas on the map. The usage of small tunnels, as in the present model, may be applied in order for the low-cost and fast studies of vast areas to the purpose of playas management.

scholarly journals Scaled wind turbine setup in a turbulent wind tunnel

2018 ◽  
Vol 1104 ◽  
pp. 012026 ◽  
Author(s):  
Frederik Berger ◽  
Lars Kröger ◽  
David Onnen ◽  
Vlaho Petrović ◽  
Martin Kühn
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Turbulent Wind

Novel Controlled-Velocity Wind Turbine Testing Apparatus to Simulate Turbulent, Non-Return Flow

2014 ◽  
Author(s):  
Corey P. Ressler ◽  
James Hilbish ◽  
Jesse J. French
Keyword(s):  
Wind Tunnel ◽  
Vertical Axis ◽  
Test Method ◽  
Return Flow ◽  
Test Apparatus ◽  
Number Range ◽  
Wind Speeds ◽  
Valid Test ◽  
Flow Interference ◽  
Work Done

This paper presents the work done by the authors to analyze the method of performance characterization of a 100W scale vertical axis wind turbines using a controlled-velocity test apparatus. The design of the power transfer system containing a gearbox and generator requires test data to determine the peak and operating range of wind speed, corresponding to RPM and torque. Multiple methods of turbine testing were considered, including in situ, wind tunnel, and control-velocity. Controlled-velocity, a method where the turbine is moved through a fluid, was selected based on lack of test location wind speeds or access to a wind tunnel of sufficient size. The test apparatus is designed to be effective for VAWT turbines of a diameter range from 1.45 to 4.2 meters in a wind velocity range of 1 to 17 m/s. This covers a Reynolds number range between (2.5 × 10^5 < Re < 4.2 × 10^6). A change from previous control-velocity test apparatus is the use of a separate truck and trailer compared to a flatbed truck, which allows greater distance between the truck cab and the turbine, to decrease any flow interference of the cab. This previous work and testing has shown to be a valid test method in that the turbine is in similar turbulent conditions as near the ground and buildings which the turbine is designed for. The main advantage of this test apparatus is the ability to test turbines in a region with low average wind speeds and minimum infrastructure.

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