On the Horizontal Homogeneity of the Atmospheric Boundary Layer Profile in CFD Simulations

2018 ◽  
Vol 12 (4) ◽  
pp. 825-829 ◽  
Author(s):  
Islam Abohela
2019 ◽  
Vol 887 ◽  
pp. 419-427
Author(s):  
Dagmara Čeheľová ◽  
Michal Franek ◽  
Boris Bielek

Aerodynamics is a relatively young scientific discipline, which started developing in the 50´s of last century. There are known several methods for calculating and measuring of the aerodynamic variables – in-situ measurements, wind tunnel measurements, CFD simulations and calculations according to national standards. Each method has its advantages and disadvantages. Nowadays a large focus is on experimental verifying the findings achieved with calculations help and CFD simulations. One of the verification possibilities are measurements in wind tunnels. The submitted paper deals with construction and using of the wind tunnel by the Slovak University of Technology in Bratislava. This device was put into operation after experimental verification in 2012, so this wind tunnel is one of the newest of its kind in Europe. The concept of the construction of individual structural elements and the wind tunnel parts has been designed in collaboration with the Aeronautical Research and Test Institute (Czech Republic) and was based on previous made analysis of aerodynamic tunnels. Its structure was designed and realized by Konštrukta Industry (Slovak Republic). We could it characterized as atmospheric boundary layer wind tunnel with open test section. It is unique with two test sections – front and back measuring space, where the front measuring space is used for uniform flow and the back measuring space is used for turbulent flow. That is why it is not only usable in the civil engineering sector (buildings, bridges, chimneys etc.), but also in city urbanism (pedestrian wind comfort and wind safety, dispersion of air pollutants), aircraft and automotive industries.


Author(s):  
Pollyana de Lima Massari ◽  
Marcos de Paula Gomes ◽  
Maria Helena Farias ◽  
Renan de Souza Teixeira

Author(s):  
Thomas G. Ivanco ◽  
Donald F. Keller ◽  
Jennifer L. Pinkerton ◽  
Kevin J. Disotell ◽  
Jesse G. Collins ◽  
...  

Author(s):  
Pierre Durand ◽  
Patrice Medina ◽  
Philippe Pastor ◽  
Michel Gavart ◽  
Sergio Pizziol

Abstract An instrumentation package for wind and turbulence observations in the atmospheric boundary layer on an unmanned aerial vehicle (UAV) called BOREAL has been developed. BOREAL is a fixed wing UAV built by BOREAL company which weighs up to 25kg (5kg of payload) and has a wingspan of 4.2m. With a light payload and optimal weather conditions, it has a flight endurance of nine hours. The instrumental payload was designed in order to measure every parameter required for the computation of the three wind components, at a rate of 100 s−1 which is fast enough to capture turbulence fluctuations: a GPS-IMU platform measures the three components of the groundspeed a well as the attitude angles; the airplane nose has been replaced by a five-hole probe in order to measure the angles of attack and sideslip, according to the so-called radome technique. This probe was calibrated using computational fluid dynamics (CFD) simulations and wind tunnel tests. The remaining instruments are a Pitot tube for static and dynamic pressure measurement, and temperature/humidity sensors in dedicated housings. The optimal airspeed at which the vibrations are significantly reduced to an acceptable level was defined from qualification flights. With appropriate flight patterns, the reliability of the mean wind estimates, through self-consistency and comparison with observations performed at 60m on an instrumented tower could be assessed. Promising first observations of turbulence up to frequencies around 10Hz and corresponding to a spatial resolution to the order of 3m, are hereby presented.


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1208
Author(s):  
Gilberto Santo ◽  
Mathijs Peeters ◽  
Wim Van Paepegem ◽  
Joris Degroote

A modern horizontal axis wind turbine was simulated by means of computational fluid dynamics (CFD) simulations. The analyzed machine has a diameter of 100 m and is immersed in the atmospheric boundary layer (ABL). The velocity and turbulence stratification of the ABL is correctly preserved along the domain by the adoption of modified wall functions. An overset technique is employed to handle the rotation of the turbine rotor throughout the operation of the machine. The ABL induces periodically oscillating loads and generated torque on the rotor blades. Several configurations are analyzed. First, the results of a rotor-only simulation are compared to the ones obtained from the simulation of the full machine in order to evaluate the effect of the supporting structures on the produced torque and on the loads acting on the blades. Then, a tilt angle is introduced on the analyzed rotor and its effect on the oscillating loads of each blade is highlighted by comparing the results to the untilted configuration. Lastly, a yaw misalignment is also introduced and the results are compared to the unyawed configuration.


Heliyon ◽  
2020 ◽  
Vol 6 (7) ◽  
pp. e04274
Author(s):  
Yousef Abu-Zidan ◽  
Priyan Mendis ◽  
Tharaka Gunawardena

2007 ◽  
Vol 25 ◽  
pp. 49-55 ◽  
Author(s):  
S. Argentini ◽  
I. Pietroni ◽  
G. Mastrantonio ◽  
A. Viola ◽  
S. Zilitinchevich

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