BOREAL- A fixed-wing unmanned aerial system for the measurement of wind and turbulence in the atmospheric boundary layer

2022 ◽  
Author(s):  
Pierre Durand ◽  
Patrice Medina ◽  
Philippe Pastor ◽  
Michel Gavart ◽  
Sergio Pizziol
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Dynamic Pressure ◽  
Weather Conditions ◽  
Cfd Simulations ◽  
Dynamic Pressure Measurement ◽  
Aerial Vehicle ◽  
Computational Fluid Dynamics Cfd ◽  
The Mean ◽  
Self Consistency

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GPS-IMU platform measures the three components of the groundspeed a well as the attitude angles; the airplane nose has been replaced by a five-hole probe in order to measure the angles of attack and sideslip, according to the so-called radome technique.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.

scholarly journals Numerical Investigation of the Effect of Tower Dam and Rotor Misalignment on Performance and Loads of a Large Wind Turbine in the Atmospheric Boundary Layer

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1208
Author(s):  
Gilberto Santo ◽  
Mathijs Peeters ◽  
Wim Van Paepegem ◽  
Joris Degroote
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Wind Turbine ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Horizontal Axis Wind Turbine ◽  
Cfd Simulations ◽  
Wall Functions ◽  
Computational Fluid Dynamics Cfd ◽  
Large Wind

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.

scholarly journals Diurnal variability of the atmospheric boundary layer height over a tropical station in the Indian monsoon region

2017 ◽  
Vol 17 (1) ◽  
pp. 531-549 ◽  
Author(s):  
Sanjay Kumar Mehta ◽  
Madineni Venkat Ratnam ◽  
Sukumarapillai V. Sunilkumar ◽  
Daggumati Narayana Rao ◽  
Boddapaty V. Krishna Murthy
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Diurnal Variation ◽  
Indian Monsoon ◽  
Winter Season ◽  
Monsoon Region ◽  
Diurnal Variability ◽  
The Mean ◽  
Indian Monsoon Region ◽  
Tropical Station

Abstract. The diurnal variation of atmospheric boundary layer (ABL) height is studied using high-resolution radiosonde observations available at 3 h intervals for 3 days continuously from 34 intensive campaigns conducted during the period December 2010–March 2014 over a tropical station Gadanki (13.5° N, 79.2° E; 375 m), in the Indian monsoon region. The heights of the ABL during the different stages of its diurnal evolution, namely, the convective boundary layer (CBL), the stable boundary layer (SBL), and the residual layer (RL) are obtained to study the diurnal variabilities. A clear diurnal variation is observed in 9 campaigns out of the 34 campaigns. In 7 campaigns the SBL did not form in the entire day and in the remaining 18 campaigns the SBL formed intermittently. The SBL forms for 33–55 % of the time during nighttime and 9 and 25 % during the evening and morning hours, respectively. The mean SBL height is within 0.3 km above the surface which increases slightly just after midnight (02:00 IST) and remains almost constant until the morning. The mean CBL height is within 3.0 km above the surface, which generally increases from morning to evening. The mean RL height is within 2 km above the surface which generally decreases slowly as the night progresses. The diurnal variation of the ABL height over the Indian region is stronger during the pre-monsoon and weaker during winter season. The CBL is higher during the summer monsoon and lower during the winter season while the RL is higher during the winter season and lower during the summer season. During all the seasons, the ABL height peaks during the afternoon (∼ 14:00 IST) and remains elevated until evening (∼ 17:00 IST). The ABL suddenly collapses at 20:00 IST and increases slightly in the night. Interestingly, it is found that the low level clouds have an effect on the ABL height variability, but the deep convective clouds do not. The lifting condensation level (LCL) is generally found to occur below the ABL for the majority of the database and they are randomly related.

scholarly journals Development of an unmanned aerial vehicle to study atmospheric boundary-layer turbulent structure

2021 ◽  
Vol 1925 (1) ◽  
pp. 012068
Author(s):  
D G Chechin ◽  
A Yu Artamonov ◽  
N Ye Bodunkov ◽  
M Yu Kalyagin ◽  
A M Shevchenko ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Turbulent Structure ◽  
Aerial Vehicle

scholarly journals A pressure-driven atmospheric boundary layer model satisfying Rossby and Reynolds number similarity

2021 ◽  
Vol 6 (3) ◽  
pp. 777-790
Author(s):  
Maarten Paul van der Laan ◽  
Mark Kelly ◽  
Mads Baungaard
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Atmospheric Boundary Layer ◽  
Wind Farm ◽  
Three Dimensional ◽  
Computation Time ◽  
Wind Farms ◽  
The Mean ◽  
The Impact ◽  
Pressure Driven

Abstract. Idealized models of the atmospheric boundary layer (ABL) can be used to leverage understanding of the interaction between the ABL and wind farms towards the improvement of wind farm flow modeling. We propose a pressure-driven one-dimensional ABL model without wind veer, which can be used as an inflow model for three-dimensional wind farm simulations to separately demonstrate the impact of wind veer and ABL depth. The model is derived from the horizontal momentum equations and follows both Rossby and Reynolds number similarity; use of such similarity reduces computation time and allows rational comparison between different conditions. The proposed ABL model compares well with solutions of the mean momentum equations that include wind veer if the forcing variable is employed as a free parameter.

Atmospheric Boundary Layer Wind Tunnel of Slovak University of Technology in Bratislava

2019 ◽  
Vol 887 ◽  
pp. 419-427
Author(s):  
Dagmara Čeheľová ◽  
Michal Franek ◽  
Boris Bielek
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Atmospheric Boundary Layer ◽  
Slovak Republic ◽  
Scientific Discipline ◽  
National Standards ◽  
Cfd Simulations ◽  
Advantages And Disadvantages ◽  
University Of Technology ◽  
Measuring Space

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.

scholarly journals Continuous Daily Observation of the Marine Atmospheric Boundary Layer over the Kuroshio by a Helicopter Shuttle Service

2015 ◽  
Vol 32 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Youichi Tanimoto ◽  
Kou Shimoyama ◽  
Shoichi Mori
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Dynamic Pressure ◽  
Japan Meteorological Agency ◽  
Observation System ◽  
Vertical Profiles ◽  
Marine Atmospheric Boundary Layer ◽  
Near Surface ◽  
Ocean Front ◽  
Observation Method

AbstractThis paper describes a new initiative in which in situ observations of the marine atmospheric boundary layer (MABL) are made by a helicopter shuttle connecting six islands south of Tokyo. This observation method aims to make frequent measurements of temperature and moisture in the MABL across an ocean front, where direct measurements of the MABL have been limited. An onboard observation system to meet flight regulations was developed. Observed temperature and moisture as a function of pressure at 1-s intervals provided vertical profiles up to the 900-hPa level above each of the islands, from 24 December 2010 to 6 April 2011, with the exception of an accidental power down in mid-February 2011. The observed values are validated by intercomparison with surface measurements from weather stations, atmospheric soundings, and mesoscale weather analysis provided by the Japan Meteorological Agency. Temperature and moisture values obtained using the system described here at the surface are significantly correlated with those from the weather station. The meridional changes revealed by the observed vertical profiles depict rich MABL structures, such as a cold-air intrusion and a strong near-surface inversion, that are not captured by the mesoscale weather analysis. However, this discrepancy is probably due to insufficient treatment in the mesoscale numerical model rather than observational errors. Additional intercomparisons indicate no influence from either artificial mixing by the helicopter rotor or by dynamic pressure caused by the fast-moving helicopter when obtaining the vertical profiles. Following these validations, the continuation of the initiative will allow for examining the influence of the ocean front on the overlying MABL on a synoptic time scale.

scholarly journals Diurnal variability of the Atmospheric Boundary Layer height over a tropical station in the Indian Monsoon Region

2016 ◽  
Author(s):  
Sanjay Kumar Mehta ◽  
Madineni Venkat Ratnam ◽  
Sukumarapillai V. Sunilkumar ◽  
Daggumati Narayana Rao ◽  
Boddapati V. Krishna Murthy
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Diurnal Variation ◽  
Indian Monsoon ◽  
Winter Season ◽  
Monsoon Region ◽  
Diurnal Variability ◽  
The Mean ◽  
Indian Monsoon Region ◽  
Tropical Station

Abstract. The diurnal variation of atmospheric boundary layer (ABL) height is studied using high resolutions radiosonde observations available every 3-h intervals for 3 days continuously from 34 intensive campaigns conducted during the period December 2010–March 2014 over a tropical station Gadanki (13.5° N, 79.2° E), in the Indian monsoon region. The heights of the ABL during the different stages of its diurnal evolution, namely, the convective boundary layer (CBL), the stable boundary layer (SBL), and the residual layer (RL) are obtained to study the diurnal variability. A clear diurnal variability in 9 campaigns is observed while in 7 campaigns the SBL does not form for the entire day and in the remaining 18 campaigns the SBL form intermittently. The SBL forms 33 %–55 % during nighttime and 9 % and 25 % during the evening and morning hours, respectively. The mean SBL height is within 0.3 km above the surface which increases slightly just after midnight (0200 IST) and remain almost steady till morning. The mean CBL height is within 3.0 km above the surface which generally increases from morning to evening. The mean RL height is within 2 km above the surface which generally decreases slowly as the night progresses. Diurnal variation of the ABL height over the Indian region is stronger during the pre-monsoon and weaker during winter season. The CBL is higher during the summer monsoon and lower during the winter season while the RL is higher during winter season and lower during summer season. During all the seasons, the ABL height peaks during the afternoon (~ 1400 IST) and remains elevated till evening (~ 1700 IST). The ABL suddenly collapses at 2000 IST due to cooling after the sunset and increases slightly over night. Interestingly, it is found that the low level clouds have an effect on the ABL height variability, but not the deep convective clouds.

scholarly journals Development of an Unmanned Aerial Vehicle for the Measurement of Turbulence in the Atmospheric Boundary Layer

Atmosphere ◽  
2017 ◽  
Vol 8 (10) ◽  
pp. 195 ◽  
Author(s):  
Brandon Witte ◽  
Robert Singler ◽  
Sean Bailey
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Sensor Data ◽  
Velocity Sensor ◽  
Aerial Vehicle ◽  
Probe Velocity ◽  
Convective State ◽  
Using Data

This paper describes the components and usage of an unmanned aerial vehicle developed for measuring turbulence in the atmospheric boundary layer. A method of computing the time-dependent wind speed from a moving velocity sensor data is provided. The physical system built to implement this method using a five-hole probe velocity sensor is described along with the approach used to combine data from the different on-board sensors to allow for extraction of the wind speed as a function of time and position. The approach is demonstrated using data from three flights of two unmanned aerial vehicles (UAVs) measuring the lower atmospheric boundary layer during transition from a stable to convective state. Several quantities are presented and show the potential for extracting a range of atmospheric boundary layer statistics.

scholarly journals Advances and limitations of atmospheric boundary layer observations with GPS occultation over southeast Pacific Ocean

2012 ◽  
Vol 12 (2) ◽  
pp. 903-918 ◽  
Author(s):  
F. Xie ◽  
D. L. Wu ◽  
C. O. Ao ◽  
A. J. Mannucci ◽  
E. R. Kursinski
Keyword(s):  
Boundary Layer ◽  
Pacific Ocean ◽  
Atmospheric Boundary Layer ◽  
Temperature Inversion ◽  
Lower Percentage ◽  
Trade Wind ◽  
Sampling Errors ◽  
Wide Range ◽  
The Mean ◽  
The Difference

Abstract. The typical atmospheric boundary layer (ABL) over the southeast (SE) Pacific Ocean is featured with a strong temperature inversion and a sharp moisture gradient across the ABL top. The strong moisture and temperature gradients result in a sharp refractivity gradient that can be precisely detected by the Global Positioning System (GPS) radio occultation (RO) measurements. In this paper, the Constellation Observing System for Meteorology, Ionosphere & Climate (COSMIC) GPS RO soundings, radiosondes and the high-resolution ECMWF analysis over the SE Pacific are analyzed. COSMIC RO is able to detect a wide range of ABL height variations (1–2 km) as observed from the radiosondes. However, the ECMWF analysis systematically underestimates the ABL heights. The sharp refractivity gradient at the ABL top frequently exceeds the critical refraction (e.g., −157 N-unit km−1) and becomes the so-called ducting condition, which results in a systematic RO refractivity bias (or called N-bias) inside the ABL. Simulation study based on radiosonde profiles reveals the magnitudes of the N-biases are vertical resolution dependent. The $N$-bias is also the primary cause of the systematically smaller refractivity gradient (rarely exceeding −110 N-unit km−1) at the ABL top from RO measurement. However, the N-bias seems not affect the ABL height detection. Instead, the very large RO bending angle and the sharp refractivity gradient due to ducting allow reliable detection of the ABL height from GPS RO. The seasonal mean climatology of ABL heights derived from a nine-month composite of COSMIC RO soundings over the SE Pacific reveals significant differences from the ECMWF analysis. Both show an increase of ABL height from the shallow stratocumulus near the coast to a much higher trade wind inversion further off the coast. However, COSMIC RO shows an overall deeper ABL and reveals different locations of the minimum and maximum ABL heights as compared to the ECMWF analysis. At low latitudes, despite the decreasing number of COSMIC RO soundings and the lower percentage of soundings that penetrate into the lowest 500-m above the mean-sea-level, there are small sampling errors in the mean ABL height climatology. The difference of ABL height climatology between COSMIC RO and ECMWF analysis over SE Pacific is significant and requires further studies.

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