Wind Profiles Research Articles

Extrapolation is not enough: impacts of extreme land use change on wind profiles and wind energy according to regional climate models

Abstract. Humans change climate in many ways. In addition to greenhouse gases, climate models must therefore incorporate a range of other forcings, such as land use change. While studies typically investigate the joint effects of all forcings, here we isolate the impact of afforestation and deforestation on winds in the lowermost 350 m of the atmosphere to assess the relevance of land use change for large-scale wind energy assessments. We use vertically resolved sub-daily output from two regional climate models instead of extrapolating near-surface winds with simplified profiles. Comparing two extreme scenarios, we report that afforestation reduces wind speeds by more than 1 m s−1 in many locations across Europe, even 300 m above ground, underscoring its relevance at hub heights of current and future wind turbines. We show that standard extrapolation with modified parameters approximates long-term means well but fails to capture essential spatio-temporal details, such as changes in the daily cycle, and it is thus insufficient to estimate wind energy potentials. Using adjacent climate model levels to account for spatio-temporal wind profile complexity, we report that wind energy capacity factors are strongly impacted by afforestation and deforestation: they differ by more than 0.1 in absolute terms and up to 50 % in relative terms. Our results confirm earlier studies showing that land use change impacts on wind energy can be severe and that they are generally misrepresented with common extrapolation techniques.

High‐Frequency Gravity Waves and Kelvin‐Helmholtz Billows in the Tropical UTLS, as Seen From Radar Observations of Vertical Wind

AbstractThe present study analyzes novel observations of vertical wind in the tropical upper troposphere‐lower stratosphere obtained from a radar wind profiler in Cochin, India. Between December 2022 and April 2023, 63 consecutive 4 hr curtains of were measured with a vertical spacing of 180 m and a sampling time step of 44 s, thus resolving almost the whole spectrum of vertical motions. Spectra of strongly vary with altitude. They are generally flat up to the local Brunt‐Väisälä frequency (BVF), but sometimes exhibit a peak of variance closer to BVF, a feature which may be attributed to trapped gravity waves. At other times and locations, the profiles reveal Kelvin‐Helmholtz billows. Finally, the variability of variance over the 4 month campaign period is investigated. Using brightness temperature from geostationary satellites as a convective proxy, it is found that variance is highly correlated with fluctuations in convective activity.

Retrieving Estimates of the Storm‐Relative Wind Profile From the Vertical Variation of Hydrometeor Size Sorting Signatures

AbstractRaindrop fall speed increases with raindrop size. Because larger raindrops fall through a given layer of the atmosphere more quickly compared to smaller raindrops, they spend less time in the layer and, therefore, have less time to be acted on and advected by the storm‐relative winds. This results in hydrometeor size sorting which impacts the polarimetric radar variables such as differential reflectivity and specific differential phase . Previous work has shown a strong correlation between the mean storm‐relative wind in the sorting layer and the separation between regions of enhanced and at the bottom of the sorting layer. This study leverages this finding, along with a simple size sorting model, to construct radar‐derived estimates of the storm‐relative wind profile. The radar‐derived “pseudo‐hodographs” are well‐correlated with the magnitude and direction of the corresponding storm‐relative wind profiles. Further, these radar‐derived estimates of the storm‐relative winds are used to calculate estimates of shear and storm‐relative helicity, which also exhibit a strong correlation.

Ultra-Short-Term Wind Power Forecasting in Complex Terrain: A Physics-Based Approach

This paper proposes a method based on Computational Fluid Dynamics (CFD) and the detection of Wind Energy Extraction Latency for a given wind turbine (WT) designed for ultra-short-term (UST) wind energy forecasting over complex terrain. The core of the suggested modeling approach is the Wind Spatial Extrapolation model (WiSpEx). Measured vertical wind profile data are used as the inlet for stationary CFD simulations to reconstruct the wind flow over a wind farm (WF). This wind field reconstruction helps operators obtain the wind speed and available wind energy at the hub height of the installed WTs, enabling the estimation of their energy production. WT power output is calculated by accounting for the average time it takes for the turbine to adjust its power output in response to changes in wind speed. The proposed method is evaluated with data from two WTs (E40-500, NM 750/48). The wind speed dataset used for this study contains ramp events and wind speeds that range in magnitude from 3 m/s to 18 m/s. The results show that the proposed method can achieve a Symmetric Mean Absolute Percentage Error (SMAPE) of 8.44% for E40-500 and 9.26% for NM 750/48, even with significant simplifications, while the SMAPE of the persistence model is above 15.03% for E40-500 and 16.12% for NM 750/48. Each forecast requires less than two minutes of computational time on a low-cost commercial platform. This performance is comparable to state-of-the-art methods and significantly faster than time-dependent simulations. Such simulations necessitate excessive computational resources, making them impractical for online forecasting.

Flow observations using nacelle lidars: A study on the University of Stavanger campus

Abstract This study deals with wind measurements on the campus of the University of Stavanger, using two continuous-wave nacelle lidars and a vertical continuous-wave profiler. Wind data is further acquired by 2-D sonic anemometers fixed to the lidars. The emphasis of the analysis is on the data gathered by the nacelle lidars. The horizontal wind speeds reconstructed from the radial velocities are compared to the recordings of the sonic anemometers and analysed in terms of mean wind profiles over the extent of the scanning circle. Standard logarithmic and power laws are fitted to the profiles to estimate site-specific parameters such as wind shear exponent and surface roughness. Turbulence characteristics in the mean wind direction, such as spectra and variances, are estimated and compared to those from the sonic anemometer. The study demonstrates the overall potential of remote sensing for wind monitoring in an urban environment. The wind velocities acquired in the individual measurement points along the nacelle lidars’ scanning circles are found to capture the flow in the monitored regions around the buildings in a realistic way. Together with the information from the vertically pointing wind profiler, the measurement data represents a valuable source for validation of related numerical models for flow in an urban area.

Wind stress modification by offshore wind turbines: A numerical study of wave blocking impacts

Offshore wind energy, as a clean and renewable resource, offers numerous advantages over onshore wind energy due to higher wind speeds and greater turbine capacity. However, the inadequate representation of wave-atmosphere interaction within the marine-atmospheric boundary layer may constrain wind resource assessments and, consequently, the design and layout of offshore wind turbines. By using the third-generation spectral wave model WAVEWATCH III, high-resolution numerical experiments which are capable of resolving the wind turbine foundation have been conducted to explore the blocking impact of wind turbine foundation on downstream wind stress. The findings provided significant insights into the factors influencing this effect, including foundation diameter, sea state, water depth, and wave directional spreading. Specifically, higher model resolution enables a more detailed characterization of wind stress distribution behind wind turbines. Increasing the foundation diameter resulted in a reduction of downstream wind stress. Notably, changes in wind stress exhibit a strong dependence on the sea state. The use of double periodic boundary conditions for the simulation domain enables an approximate representation of the entire wind farm by using a single turbine. Model results indicate that after waves pass through 20 turbines, domain-averaged wind stress decreases by approximately 3%, a figure that increases to 6% after passing through 50 turbines. The findings suggest the need to explore to what extent the changes in wind stress can alter wind profiles and how to parameterize the blocking impact of turbine foundations in wave models. This could have significant implications for wind farm site selection and layout design.

Effects of oncoming wind speed and turbulence intensity on wind characteristics of a simplified hill and ridge

Supertall buildings and long-span bridges are significantly affected by wind-induced vibrations, and the wind fields in mountainous areas are highly complex and influenced by the oncoming wind speed and turbulence intensity. To accurately determine the variation patterns of wind characteristics in mountainous areas under different oncoming wind speeds and turbulence intensities, large eddy simulation (LES) was employed to analyze wind fields over simplified hill and ridge models. By setting different basic wind speeds (5, 10, 15, and 20 m/s) and turbulence intensities (1%, 3%, 5%, and 10%) at the inlet, the variation patterns of wind characteristics over the simplified hill and ridge under atmospheric boundary layer inflow were studied, revealing wind field flow mechanisms. The results indicate that the wind characteristics on the leeward side of the simplified hill and ridge are significantly influenced by the oncoming wind speed and turbulence intensity. Increasing the oncoming wind speed and turbulence intensity leads to decreased wind profile deceleration, reduced changes in wind direction and attack angles, and increased wind speed amplification factor. In addition, the turbulence fluctuations, power spectra, and coherence function between two points on the leeward side increase with the oncoming wind speed and turbulence intensity. The turbulent integral scale decreases with an increase in the oncoming wind speed and turbulence intensity. As the wind speed and turbulence increase, the size of the recirculation bubble gradually decreases, with its center moving closer to the wall surface. In the vorticity field, the number of smaller-scale three-dimensional turbulent vortices near the hill and ridge increases. These differences in flow characteristics are the fundamental causes of the changes in wind characteristics. High wind speeds and turbulence intensities typically result in higher kurtosis and skewness, with significant non-Gaussian characteristics in the fluctuating wind. Traditional wind load design specifications for building architecture based on a Gaussian distribution may not be applicable to mountainous terrain. In practical engineering, the influences of the oncoming wind speed and turbulence intensity on wind characteristics should be fully considered.

A Rare Tropical Cyclone Associated With Southwest Monsoon Over the Northern Part of the South China Sea—Tropical Storm Maliksi

AbstractThis study examines the characteristics and development of Tropical Storm Maliksi, which is a special case of tropical cyclone developed in the northwestern part of the South China Sea during a southwest monsoon outbreak. Detailed analyses were conducted using observational data and forecast products. Surface observations, radar wind profilers, aircraft data, and satellite products were used to evaluate Maliksi's wind structure, revealing multiple circulation centers and gale force winds. Vertical wind profiles, warm core structure, wind waves, and the influence of sea temperatures and salinity on Maliksi's intensification were investigated. Regarding forecasting, AI‐based models outperformed conventional numerical weather prediction (NWP) models in predicting Maliksi's initial development, though both struggled to capture the persistence of strong winds as the system moved inland. High‐resolution NWP simulations were employed to examine terrain‐induced wind variability around Hong Kong International Airport, revealing the mountain wake effect and uneven wind and turbulence distribution. These findings provide insights into the challenges of forecasting and monitoring such tropical cyclones, and highlight the need for enhanced observational platforms and forecasting tools along coastlines vulnerable to these systems.

Catch the wind: Optimizing wind turbine power generation by addressing wind veer effects.

Wind direction variability with height, known as "wind veer," results in power losses for wind turbines (WTs) that rely on single-point wind measurements at the turbine nacelles. To address this challenge, we introduce a yaw control strategy designed to optimize turbine alignment by adjusting the yaw angle based on specific wind veer conditions, thereby boosting power generation efficiency. This strategy integrates modest yaw offset angles into the existing turbine control systems via a yaw-bias-look-up table, which correlates the adjustments with wind speed, and wind veer data. We evaluated the effectiveness of this control strategy through extensive month-long field campaigns for an individual utility-scale WT and at a commercial wind farm. This included controlling one turbine using our strategy against nine others in the vicinity using standard controls with LiDAR-derived wind veer data and a separate 2.5 MW instrumented research turbine continuously managed using our method with wind profiles provided by meteorological towers. Results from these campaigns demonstrated notable energy gains, with potential net gains exceeding 10% during extreme veering conditions. Our economic analysis, factoring in various elements, suggests an annual net gain of up to approximately $700 K for a 100-MW wind farm, requiring minimal additional investment, with potential for even larger gains in offshore settings with the power of individual turbines exceeding 10 MW nowadays. Overall, our findings underscore the considerable opportunities to improve individual turbine performance under realistic atmospheric conditions through advanced, cost-effective control strategies.

Comparative analysis of multiple observation data during two typhoons affecting Hainan Island

Based on different observation data, the wind and rain processes of two typhoons that continuously affected Hainan Island in October 2021 were compared and analyzed. The analysis shows that the two typhoons are similar in weather conditions, water vapor transport conditions, cold air intrusion, sea surface temperature providing energy, and so on. The spatial distribution of rainfall and wind field exhibits an evidently asymmetrical structure. Before the typhoon landed, the gale area was located mainly in the northeast of the typhoon center. Furthermore, different detection data have advantages and disadvantages, which should be verified and used each other. For example, there are also differences between radar echo reflectivity, wind profile radar data and MTCSWA data. By means of analysis and research, the ability to analyze and articulate the typhoon impact process with high spatial-temporal resolution data is further enhanced, thereby aiding in the forecast and service work during the typhoon period.

Using Adjoint-Based Forecast Sensitivity to Observation to Evaluate a Wind Profiler Data Assimilation Strategy and the Impact of Data on Short-Term Forecasts

A wind profiler radar detects fine spatiotemporal resolution dynamical information, enabling the capture of meso- and micro-scale systems. Experience gained from observing system experiments (OSEs) studies confirms that reasonable profiler assimilation techniques can achieve improved short-term forecasts. This study further applies the adjoint-based forecast sensitivity to observation (FSO) method to investigate the quantitative impact of a profiler data assimilation strategy on short-term forecasts, and the results are consistent with those obtained from OSEs, further demonstrating that FSO and OSEs can be used to evaluate the effect of data assimilation techniques from different perspectives. Considering the unique advantage that the FSO can quantify the interactions between various observing systems and the impact on improving the model forecasts according to specific needs without costly additional calculations, we further diagnose in detail the observation impacts from multiple perspectives, including the observation platform, observation variables, and spatial distribution. And the results show that dynamical variables are more significant in improving forecasts compared to the other observed variables. Meanwhile, the dense profiler observations resulted in a more significant impact when radiosonde observations were not detected. The upper-level single winds monitored by profiler radars play a more important role in improving forecast skill. The FSO method measures the impact of an individual observing system, which can be used to enrich the evaluation of data assimilation schemes, efficiently calculate the impacts of multisource observations, and contribute to future development in adaptive observation, observation quality control, and observation error optimization.

Effects of Inflow Turbulent Coherent Structures on a Small-Scale Wind Turbine in the Atmospheric Boundary Layer of Long Corridor Terrains: An Example Study in the Hexi Corridor

Considering its Venturi effect, long corridor terrain is considered as one of the outstanding wind-energy resources, but has not been developed due to unclear inflow turbulence effects on wind turbines. To advance the wind-power technology in long corridors and reveal the physics behind it, we conducted a series of data-fusion analyses combining field measurements in the Hexi Corridor, Gansu, China, and numerical simulations and summarize the effort here. In this study, the classical spectrum for the atmospheric boundary layer for wind-energy research, the IEC Kaimal spectrum (also known as IECKwind, International Elector technical Commission 61400-1) cannot describe the wind profile in corridors. Here, we proposed a new spectrum to describe the wind in the Hexi Corridor by modifying the IEC Kaimal spectrum, and we call it the IECK-HX spectrum. The results demonstrate that it preferentially resides at lower frequencies (larger spatial scales) compared with IECKwind. Large-scale motions (LSMs) and very large-scale motions (VLSMs) coexist in the Hexi Corridor atmospheric boundary layer, which can be well described by the IECK-HX spectrum, and these two dominate the large fluctuations in the power, thrust, and blade root flapwise moment of wind turbines, while the high-frequency small-scale coherent structures mainly cause high-frequency fluctuations in wind-turbine load. Furthermore, IEC Kaimal spectrum can not describe the VLSMs, and the generated flow presents significant fluctuations and thereby reduces the power output in high wind-speed regions. This study provides fundamental support for wind-energy scientists and engineers who are interested in wind energy in corridor terrains. Published by the American Physical Society 2024

Characterizing surface pressure and wind fields of typhoons approaching Hong Kong

In this paper, 17 severe typhoons that have affected Hong Kong are simulated using an advanced numerical atmospheric simulation system - Weather Research and Forecasting model (WRF). The simulated surface pressure and wind fields of these typhoons are validated against a wide range of field observations. Then azimuth-dependent models for the radius of maximum winds and the Holland parameter are established statistically at the surface level. It is observed that the shape parameter of the Holland pressure model is smaller at the surface than that at the gradient level. And the Holland wind field model cannot well reproduce the simulated radial wind profiles due to the complexities of nonuniform surface conditions and typhoon dynamics. It is found that the modified Rankine model provides satisfactory estimates of typhoon wind speeds in Hong Kong. Additionally, wind field asymmetries of typhoons approaching Hong Kong are highly correlated with the typhoon track velocity, vertical wind shear and the angle between them. The proposed statistical models and identified characteristics of wind field asymmetries of typhoons will provide useful information for rapidly assessing typhoon wind hazards.

Simulation of the Neutral Atmospheric Flow Using Multiscale Modeling: Comparative Studies for SimpleFoam and Fluent Solver

The reproduced planetary boundary layer (PBL) wind is commonly applied in downscaled simulations using commercial CFD codes with Reynolds-averaged Navier–Stokes (RANS) turbulence modeling. When using the turbulent inlets calculated by numerical weather prediction models (NWP), adjustments of the turbulence eddy viscosity closures and wall function formulations are concerned with maintaining the fully developed wind profiles specified at the inlet of CFD domains. The impact of these related configurations is worth discussing in engineering applications, especially when commercial codes restrict the internal modifications. This study evaluates the numerical performances of open-source OpenFOAM 2.3.0 and commercial Fluent 17.2 codes as supplementary scientific comparisons. This contribution focuses on the modified turbulence closures to incorporate turbulent profiles produced from mesoscale PBL parameterizations and the modified wall treatments relating to the roughness length. The near-ground flow features are evaluated by selecting the flat terrains and the classical Askervein benchmark case. The improvement in near-ground wind flow under the downscaled framework shows satisfactory performance in the open-source CFD platform. This contributes to engineers realizing the micro-siting of wind turbines and quantifying terrain-induced speed-up phenomena under the scope of wind-resistant design.

Propagation of untwisting solar jets from the low-beta corona into the super-Alfvénic wind: testing a solar origin scenario for switchbacks

Parker Solar Probe's (PSP) discovery of the prevalence of switchbacks (SBs), localised magnetic deflections in the nascent solar wind, has sparked interest in uncovering their origins. A prominent theory suggests these SBs originate in the lower corona through magnetic reconnection processes, closely linked to solar jet phenomena. Jets are impulsive phenomena, observed at various scales in different solar atmosphere layers, associated with the release of magnetic twist and helicity. This study examines whether self-consistent jets can form and propagate into the super-Alfvénic wind, assesses the impact of different Parker solar wind profiles on jet dynamics, and determines if jet-induced magnetic untwisting waves display signatures typical of SBs. We employed parametric 3D numerical magnetohydrodynamics (MHD) simulations using the Adaptively Refined Magnetohydrodynamics Solver (ARMS) code to model the self-consistent generation of solar jets. Our study focuses on the propagation of solar jets in distinct atmospheric plasma beta and Alfvén velocity profiles, including a Parker solar wind. We explored the influence of different atmospheric properties thanks to analysis techniques such as radius-time diagrams and synthetic in situ velocity and magnetic field measurements, akin to those observed by PSP or Solar Orbiter. Our findings demonstrate that self-consistent coronal jets can form and then propagate into the super-Alfvénic wind. Notable structures such as the leading Alfvénic wave and trailing dense-jet region were consistently observed across different plasma beta atmospheres. The jet propagation dynamics are significantly influenced by atmospheric variations, with changes in Alfvén velocity profiles affecting the group velocity and propagation ratio of the leading and trailing structures. U-loops, which are prevalent at jet onset, do not persist in the low-beta corona but magnetic untwisting waves associated with jets exhibit SB-like signatures. However, full-reversal SBs were not observed. These findings may explain the absence of full reversal SBs in the sub-Alfvénic wind and illustrate the propagation of magnetic deflections through jet-like events, shedding light on possible SB formation processes.

Aspect sensitivity measurement of backscattering radar echoes from 205 MHz Stratosphere–Troposphere radar at a tropical coastal station

Aspect sensitivity in VHF radar refers to the extent to which the power and spectrum width of echoes vary with changes in the zenith angle, which is related to the backscattering process. The scattering of clear air signals is primarily caused by Fresnel reflection, anisotropic scattering, and isotropic scattering. The aspect sensitivity and accuracy of moment and wind estimation in clear air radars are influenced by the beam width, beam pointing angle from zenith, and atmospheric conditions. This study proposes a method to determine the sensitivity of the recently developed Stratosphere–Troposphere (ST) wind profile Radar in Cochin, India (10.04°N, 76.33°E). The radar operates at a distinct frequency of 205 MHz in the far VHF band. The experiment is conducted at an altitude of 5 to 20 km above the ground by adjusting the beam’s orientation with a resolution of 2°in both the east–west and north-south directions. The estimation of wind components is subject to uncertainty due to the varying aspect angles caused by the distinct dispersion properties in this height range. The study found that power variance is lowest between 6 and 12 km in both north-south and east–west directions, while daily fluctuations in aspect-sensitive echoes complicate wind component estimation. Correlation length (ζ) ranges from 0.5 to 15 m, indicating various air scattering processes. Notably, θs is smaller near the zenith and increases with tilt angles, exceeding 20°up to 14 km before declining at higher altitudes, indicating significant anisotropy at elevated levels. The wide range of R factor values (0.1 to 0.9) across different heights causes significant ambiguity in wind estimation. In this study, the impact of various aspect sensitivity parameters on wind estimation on days with clear air has been analyzed.

Low‐Level Jet and Its Effect on the Onset of Summertime Nocturnal Rainfall in Beijing

AbstractLow‐level Jets (LLJs) play a critical role in triggering nocturnal rainfall in many areas on our planet. Nevertheless, little is known regarding the vertically resolved evolution of LLJs preceding rainfall. Here, the high‐resolution wind measurements from a radar wind profiler network in Beijing are used to monitor the continuous evolution of boundary‐layer jets (BLJs) and synoptic‐system‐related LLJs (SLLJs) before nocturnal rainfall under the southwesterlies synoptic pattern for the summers of 2020–2023. The results show that inertial oscillations precede LLJ‐induced nocturnal rainfall. The typical northward propagation of LLJ is driven primarily by horizontal advection. Starting 48 min before rainfall, the BLJ nose rapidly strengthens and moves downward from 0.8 km above ground level (AGL), while the SLLJ nose moves upward to 2.4 km AGL. This leads to enhanced moisture transport and convergence, which triggers nocturnal rainfall. The findings are of great significance for improving the forecast skill of nocturnal rainfall.

Noise propagation variations over long distances over water

This paper investigates the short temporal variations of noise propagation over a water surface for long distances. Analysis is formed on the results of a measurement campaign for downwind noise propagation over water for elevated sound sources. Noise propagation over water for elevated noise sources is specifically relevant for offshore wind turbines, near shore wind turbines or wind turbines on land close to large water bodies. The measurement setup is a height-adjustable sound source placed at three different heights 81 m, 50 m and 30 m above ground and microphones positioned downwind at shore and ~100 m inland at three different distances over water from the sound source ~3 km, ~5 km and ~7 km. The meteorological conditions wind speed, wind direction, atmospheric stability, temperature, humidity, etc. were monitored continuously at both ends of the setup, utilizing both a tall met mast, a wind profiler and sonic anemometers at multiple heights. The results are used for improving auralisations of noise from offshore wind turbines and offshore wind farms. In addition to this a semi-analytical model for propagation over water is tested.

Development and distribution of an in situ experimental wind turbine noise database

The PIBE project is the first French collaborative research project on wind turbine noise. One of its objectives is to quantify the experimental dispersion observed in situ on acoustic quantities/metrics and influencing parameters, and to compare it with the numerical dispersion estimated using acoustic propagation models. A long-term experimental campaign was carried out over consecutive 410 days around a wind farm comprising eight 80-metre-high and 90-metre diameter turbines. Acoustic sensors (five Class I sound level meters) were deployed on site, recording third-octave spectra and overall A- and Z-weighted values of the Leq indicator and fractile indices (L10, L50 and L90), at distances from 325 m to 1400 m from the wind turbines row. In addition, three 3D ultrasonic anemometers and a Lidar system were used to measure meteorological variables influencing long-range sound propagation (e.g. wind and temperature verical profiles). Besides, train and aircraft passing close to the site were inventoried to identify periods of high background noise. All experimental data have been processed into an ElasticSearch database. An interactive web application has been developed in R Shiny to facilitate processing, visualization and analysis of the experimental database.

Modeling of a moving point source in inhomogeneous and turbulent media - Application to aircraft noise

Engineering solutions for the modeling of aircraft noise often rely on simplified approaches that consider quasi-static sources and homogenous propagation conditions. These hypothesis may lead to significant inaccuracies on sound pressure level predictions in certain configurations, especially for source traveling at high mach number and at several hundred meters from the receiver. In order to overcome these limitations, an efficient numerical model based on the coupling of a heuristic formulation and a ray-tracing model is proposed. The modeling takes into account source motion effect (Doppler effect and convective amplification), as well as the sound propagation phenomena in inhomogeneous media (waves refraction and scattering by atmospheric turbulence). Several case study related to aircraft noise are presented, for which wind and temperature profiles correspond to experimental measurements. The influence of atmospheric turbulence for such configuration is finally discussed. This work is part of the program MAMBO (Advanced methods for engine and aicraft noise modelling" coordinated by Airbus SAS and supported by the Direction Générale de l'Aviation Civile (DGAC).