Turbulent Wind Flow Research Articles

ИССЛЕДОВАНИЕ ОБОЛОЧКИ ТИПА ГИПЕРБОЛИЧЕСКОГО ПАРАБОЛОЇДА В АЭРОДИНАМИЧЕСКОЙ ТРУБЕ И СРАВНЕНИЕ С ЧИСЛЕННЫМ МОДЕЛИРОВАНИЕМ

There are different ways to determine aerodynamic parameters, using analytical and experimental data for analyzing the behavior of structures when exposed to wind load. To date, the most developed is considered a numerical method for determining the characteristics of the above methods, based on the numerical solution of the Navier-Stokes equations. The accuracy of the results obtained using such a calculation method and obtaining the values of aerodynamic forces has increased due to the revision of mathematical models and the development of software complexes for the discretization of object bodies. This article gives an analytical overview of the results of research in the field of study the impact of wind loads on hypar (shell square in plan with the form of a hyperbolic paraboloid). The features of the investigated forms a discretization surface depending on pressure coefficients obtained in foreign literatures. Particular attention is paid to the numerical determination of aerodynamic coefficients on the surfaces of a hyperbolic paraboloid. The results were discussed and the nature of the distribution of coefficients depending on the angle of attack of the wind. Achieved analytical comparison computer modeling turbulent wind flows, based on solving the Reynolds equations arising from the use of averaging the Navier-Stokes equations. The basic model of turbulence such as: k-ε Standard Model; MMK; DBN; Shear-Stress Transport k-ω model; Transition k-kl-ω model. The possibility of choosing one or another model depending on the properties and characteristics of the wind flow is analyzed, for application in numerical simulation of wind flow around hyperbolic shells. The same was done, a comparative analysis of the results of physical testing in a wind tunnel with a numerical simulation in Ansys Fluent.

Wind-induced responses of a tall chimney by aeroelastic wind tunnel test using a continuous model

This study aims to investigate wind-induced responses of a 300 m high chimney by using wind tunnel tests on an aeroelastic model. Due to the fact that it is unrealistic to simulate wind flow with a high Reynolds number as high as 1 × 108 for a chimney model in a wind tunnel, roughness paper strips were attached to the model surface to artificially achieve effective high Reynolds number flow in the full-scale condition. An optimal thickness of the roughness paper strips was determined via a series of pressure measurement tests on a rigid model of the chimney. To examine wind-induced responses of the chimney, a continuous aeroelastic chimney model was manufactured with the DEVCON plastic steel liquid. After roughening the aeroelastic model by the paper strips with the optimal thickness, a series of wind tunnel tests were conducted on the model to directly acquire the structural responses, for three different oncoming wind flow conditions. Results show that the response of the roughened model is much smaller than that for the model without roughness element, indicating that ignoring the Reynolds number effect will overestimate the response. The across-wind acceleration response of the chimney is more considerable than that in the along-wind direction, when the reduced wind velocity Vr is larger than 4. In addition, the across-wind acceleration response is usually larger in the more turbulent wind flow, although the lock-in phenomenon is more evident in uniform flow.

CFD prediction of dust pollution and impact on an isolated ground-mounted solar photovoltaic system

Abstract This paper numerically studied dust deposition behaviors and their influences on an isolated ground-mounted solar PV system. The shear stress transport k-ω turbulence model with user-defined function inlet profiles was established to predict turbulent air flow around solar PV system. Moreover, discrete particle model was employed to predict dust deposition rates on PV panel. After grid independent study and numerical validation with related experimental data, turbulent wind flow fields around solar PV system, dust deposition rates on PV panel with different dust diameters and wind velocities as well as their influences on the output efficiency for different types of PV modules were predicted and analyzed carefully. The results showed that dust deposition rate on PV panel first increases and then decreases when dust diameter increases. However, the dust deposition profiles are similar for different wind velocities. The highest deposition rate is 13.71% for 100 μm particles when UHp = 1.3 m/s (UHp is wind velocity at solar PV panel height) while is 14.28% for 150 μm particles when UHp = 2.6 m/s. The effects of interception, gravitation and mass inertia are the main mechanisms for dust deposition. Furthermore, dust deposition effect on PV output efficiency was predicted by a simplified model based on present computational fluid dynamics simulation and experimental measurement.

Evolutionary power spectral density of recorded typhoons at Sutong Bridge using harmonic wavelets

The rapid development of structural health monitoring system (SHMS) over last decades makes the accurate monitoring of structural responses and surrounding environments possible. The obtained wind speed data during recorded typhoons typically show significant non-stationary features. Run-test method was employed to verify the stationarity of the recorded wind speed data. To investigate the non-stationary characteristics of recorded typhoons, the evolutionary power spectral densities (EPSDs) of four typhoons at Sutong Bridge site were estimated based on the wavelet transform (WT). A numerical experiment was conducted to identify the proper wavelet bases in the estimation of the EPSDs for non-stationary turbulent wind flows. Specifically, recorded data of typhoons Fung-wong, Meari, Damrey, and Matmo from the SHMS on Sutong Bridge were utilized to calculate the EPSDs using the generalized harmonic wavelet (GHW) and the filtered harmonic wavelet (FHW). The EPSDs estimated by GHW and FHW were comparatively investigated. The normalized Kaimal EPSDs were also compared with the normalized recorded EPSDs of the four typhoons. Results show that the HW-based EPSD estimations for the recorded typhoon data are accurate and reliable. The EPSDs estimated by FHW show the optimum time resolution in comparison with GHW and Morlet wavelet. The energy of the recorded wind speed data mainly concentrates in low-frequency band. The Kaimal EPSDs may be not appropriate to depict the evolutionary features of recorded data during typhoons Fung-wong and Matmo in this study. This observation may provide reference values for wind effect analysis on the long-span bridges with low natural frequencies.

Numerical simulation of the effect of wind barrier openings on high-speed wind flow around a heliostat field

• A two-dimensional numerical simulation was conducted. • We investigated the effect of varying the wind barrier opening size on wind flow. • We analyzed the vertical profile of wind velocity and turbulence kinetic energy in the domain considered. • We proposed the recommended wind barrier opening size for reduction of wind velocity and turbulence kinetic energy. The application of heliostats for solar power tower plants has increased in recent years. Most of the solar power tower plants installed are on flat terrain, and they may be subjected to wind loads. In the present study, a two-dimensional numerical simulation of turbulent high-speed wind flow around a heliostat field was analyzed and the wind barrier effect on the flow was investigated with use of the computational fluid dynamics commercial code COMSOL ( k - ε turbulence model). The calculation was performed for different configurations of wind barriers with opening sizes of 0 m, 0.2 m, 0.5 m, and 1 m, respectively, and four heliostat orientations in each case: 0°, 30°, 60°, and 90°. The results show that the use of wind barriers reduces wind velocity in a solar power tower plant. We found that wind barriers with small openings (0.2 m and 0.5 m) are effective in reducing wind speed below 10 m from the ground and create, at the same time, less turbulence kinetic energy than the other configurations (0 m and 1 m).

Numerical Investigation of the Turbulent Wind Flow Through Elevated Windbreak

Analysis of airflow through elevated windbreaks is presented in this paper. Permeable nets and impermeable film increases considerable wind forces on the windbreaks which is susceptible to damage during high wind. A comprehensive numerical investigation has been carried out to analyze the effects of wind on standalone elevated windbreak clad with various permeable nets and an impermeable film. The variation of airflow behavior around and through permeable nets and airflow behavior around impermeable film were also been investigated. Computational fluid dynamics techniques using Reynolds Averaged Navier–Stokes equations has been used to predict the wind force coefficient and thus wind forces on panels supporting permeable nets and impermeable film for turbulent wind flow. Elevated windbreak panels were analyzed for seven different permeable nets having various solidity ratio, specific permeability and aerodynamic resistant coefficients. The permeable nets were modelled as porous jump media obeying Forchheimer’s law and an impermeable film modelled as rigid wall.

Unsteady galloping of a rectangular cylinder in turbulent flow

Slender structures with a bluff non-axisymmetric cross-section are prone to both vortex-induced vibration (VIV) and transverse galloping. When the mass-damping parameter of the system is low, the two phenomena can interfere giving rise to a peculiar type of instability, for which the quasi-steady theory does not apply, and therefore which one may call “unsteady galloping”. Since for large structures (such as high-rise towers or bridge pylons) this phenomenon seems to be potentially an issue, rather than the quasi-steady galloping, it is particularly important to verify whether the former also occurs in realistic turbulent wind flows, and to understand its specific features. With this aim in mind, static and dynamic wind tunnel tests have been carried out on a two-dimensional rectangular cylinder with a side ratio of 1.5 (having the short side perpendicular to the flow) immersed in various grid-induced homogeneous isotropic turbulent flows. From a quasi-steady perspective, the static tests showed the proneness to galloping instability of the considered cross-section even in highly turbulent flow, though strongly dependent on the integral length scale of turbulence. In addition, they revealed an attenuation of the strength of vortex shedding, but suggested an increased tendency of VIV and galloping to interfere as compared to the smooth-flow case. The dynamic tests confirmed this tendency and highlighted a complicated behavior of the model in turbulent flow, with some features that still remain unexplained. In particular, even larger values of the mass-damping parameter of the system are necessary for the quasi-steady theory to be able to predict correctly the galloping instability threshold. Another important result is that the integral scale of turbulence was found to play a key role also in the unsteady galloping behavior of the considered rectangular cylinder.

Aerodynamic admittances of bridge deck sections: Issues and wind field dependence

Two types of aerodynamic admittance function (AAF) that have been adopted in bridge aerodynamics are addressed. The first type is based on a group of supposed relations between flutter derivatives and AAFs. In so doing, the aero-elastic properties of a section could be used to determine AAFs. It is found that the supposed relations hold only for cases when the gust frequencies are within a very low range. Predominant frequencies of long-span bridges are, however, far away from this range. In this sense, the AAFs determined this way are of little practical significance. Another type of AAFs is based on the relation between the Theodorsen circulation function and the Sears function, which holds for thin airfoil theories. It is found, however, that an obvious illogicality exists in this methodology either. In this article, a viewpoint is put forward that AAFs of bluff bridge deck sections are inherently dependent on oncoming turbulent properties. This kind of dependence is investigated with a thin plate and a double-girder bluff section via computational fluid dynamics method. Two types of wind fluctuations are used for identification of AAFs. One is turbulent wind flow while the other is harmonic. The numerical results indicate that AAFs of the thin plate agree well with the Sears AAF, and show no obvious dependence on the oncoming wind fields. In contrast, for the case of bluff double-girder section, AAFs identified from the turbulent and harmonic flows of different amplitudes differ among each other, exhibiting obvious dependence on the oncoming wind field properties.

Detached eddy simulation of pedestrian-level wind and gust around an elevated building

Wind flow turbulence is known to have a major influence on the pedestrian-level wind (PLW) environments, particularly around a building. The elevated design of a building, as a special feature, proved to improve pedestrian-level weak wind conditions in high-density cities. The present study aims to assess three turbulence models, the detached eddy simulation (DES), the steady-state RANS (SRANS), and the unsteady-state RANS (URANS), in their simulation of the PLW flow turbulence concerning wind gust. The simulated mean wind velocities around isolated buildings with and without an elevated design were compared with those obtained from a wind tunnel experiment. The effects of mesh resolution and inflow fluctuating algorithm on the performance of the DES model were thoroughly evaluated. The DES model can better reproduce the mean flow fields than the other two models. Finally, the unsteady fluctuations of wind flow around the buildings with and without the elevated design are analyzed in terms of instantaneous wind velocity, lift coefficient, energy spectral density, and turbulence intensity. The predicted lift coefficient and Strouhal number are approximately 0.01 and 0.09, respectively, which is consistent with what are reported in the literature. Modifications of the frequency of vortex shedding, periodical wind flow pattern, and the normalized wind gust flow fields around the two types of buildings are compared in detail. The work reveals that transient turbulent flow pattern can be reasonably obtained with the DES model, indicating the potential of using the DES for PLW gust assessments in urban planning.

Adaptation of Aircraft’s Wings Elements in Turbulent Flows by Local Voting Protocol

Miniaturization and increased performance calculators, sensors and actuators are opening up the new possibilities of intelligent control complex mechatronic systems under the transient and turbulent conditions. Earlier adaptive control in a changing environment and with time-varying structure of the state space explored slightly due to the limited possibilities of practical implementation. The paper considers the model of an aircraft with a large number of sensors and actuators, distributed over surfaces of wings. In turbulent wind flows, it is shown that the multi-agent Local Voting Protocol with non-decreasing to zero step size allows equalization effects of disturbing forces acting on the different elements of wings.

A semi-empirical model for vortex-induced vertical forces on a twin-box deck under turbulent wind flow

Long-span cable-supported bridges with twin-box decks have been constructed in recent years to enhance the stability of the bridges against flutter, but some of these bridges suffer large-amplitude vortex-induced vibration (VIV). Large-amplitude VIV can cause fatigue damage accumulation in structural components and reduce safety and comfort levels of road vehicles, trains, and pedestrians. Therefore, in the design of long-span bridges with twin-box decks, it is essential to know vortex-induced forces (VIF) and predict vortex-induced responses (VIR). Currently, there are several semi-empirical models for the estimation of VIF but most of them are established based on measured VIR for single-box decks and without considering turbulent wind effects.This paper presents a semi-empirical model for vertical VIF on a twin-box deck with and without turbulent wind flow. First, the two existing semi-empirical single-degree-of-freedom (SDOF) VIF models are discussed, and a refined SDOF model for VIF under smooth wind flow is proposed. The proposed SDOF VIF model includes all the non-conservative motion-induced force terms. An approximate analytical solution for the maximum amplitude of VIR is then deduced based on the proposed VIF model. Second, based on quasi-static assumption, the proposed VIF model is further extended to take account of turbulence wind effects by introducing a turbulence-induced positive damping term into the model. Finally, the validity of the proposed VIF model with and without turbulent wind effects is examined using a newly-developed wind tunnel test technique for an elastically-mounted twin-box section model. The comparative results show that the proposed VIF model can effectively predict the maximum VIR of a twin-box deck under different turbulent fields with different structural damping ratios. It is also found that the maximum VIR decreases nonlinearly with the increase of turbulence intensity.

Pedestrian Level Turbulent Wind Flow around an Elevated Building

Wind flow turbulence plays a critical role in the pedestrian level wind environment, particularly for the airflow around buildings with specific architectural features. The elevated design, a feature was proved to improve the pedestrian level weak wind conditions in high-density cities in our earlier study. This present study aims to further investigate the pedestrian level wind flow turbulence in an elevated building surrounding. The predictions were conducted by comparing the CFD simulation and a wind tunnel experiment. Specifically, the Detached Eddy Simulation (DES), the Steady-state and the Unsteady-state RANS (SRANS and URANS), were assessed. The effects of mesh resolutions and inflow fluctuating algorithms on the performance of the DES model were thoroughly evaluated. DES can better reproduce the mean flow fields than the other two models. The unsteady flow fluctuations around the elevated building are analyzed with energy spectral density. Meanwhile, the periodical wind flow fields around the elevated building are accurately obtained.

Wind effect on full-scale design of heliostat with torque tube

Despite the importance of designing support structures for solar collectors, very little reliable work has been done to investigate the forces of the wind on heliostats of solar tower at real scale. Wind loads on heliostats are usually determined at low-speed wind tunnels scale, where the design full-scale Reynolds number cannot be reached. In the present study, measured data are used to validate the simulations at wind tunnel scale. Thereafter, by using the same method, three-dimensional numerical simulations of turbulent wind flow around a big heliostat of solar tower are performed. The obtained numerical results are presented for several elevation angles at normal operation and stow position. The results revealed that the known stow position (when the backside of the heliostat is facing the ground) is not the optimum position (other optimum elevation angles are discovered) especially with high wind speed, and the effect of torque tube is significant on heliostat mean wind loads.

Computational bridge aeroelasticity using turbulence models

AbstractLong‐span bridges may collapse due to the interaction of turbulent wind flow and structural motion. The investigation of the fluid‐structure interaction requires appropriate models for the structure, the wind flow and the coupling between them. Modeling and simulation of the wind flow is still a challenging aspect. The aim of this paper is to show the application of Reynolds Averaged Navier‐Stokes (RANS) equations with a turbulence model in the context of bridge aeroelasticity. (© 2016 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Performance and dynamic characteristics of a multi stages vertical axis wind turbine

Vertical axis wind turbines (VAWTs) are used to convert wind energy to mechanical output or electricity. Vertical axis wind turbines are favorable at buildings as it can receive wind from any direction, have a design that can be integrated simply with building architecture and they have better response in turbulent wind flow which is common in urban areas. Using a calculation code based on the Double Multiple Stream Tube theory, symmetrical straight-bladed NACA0012 wind turbine performance was evaluated. The induction factor for both upwind and downwind zone is determined with the aid of a root-finding algorithm. This numerical analysis highlighted how turbine performance is strongly influenced by the wind speed (Reynolds number) and rotor solidity (turbine radius and blade chord length). Also a dimensional analysis is introduced and is to be considered in such a way to generalize the design for different turbine specifications. One of the qualities provided by dimensional analysis is that geometrically similar turbines will produce the same non-dimensional results. This allows one to make comparison between different sizes wind turbines in terms of power output and other related variables. One of the main problems affecting the turbine performance and dynamics is the torque ripple phenomena. So in this paper a turbine design configuration is introduced in order to decrease the turbine torque fluctuation. This design is carried out by constructing more similar turbine units (stages) on the vertical axis on top of each other with different orientation phase angles. The results showed that using even number of turbine assembly is better than odd number to avoid torque fluctuation and mechanical vibrations acting on the turbine. Also it is preferred to use four turbine stages as the eight stages will have no sensible effect on decreasing the torque fluctuation.

Dynamics of skimming flow in the wake of a vegetation patch

Abstract Dryland vegetation is often spatially patchy, and so affects wind flow in complex ways. Theoretical models and wind tunnel testing have shown that skimming flow develops above vegetation patches at high plant densities, resulting in little or no wind erosion in these zones. Understanding the dynamics of skimming flow is therefore important for predicting sediment transport and bedform development in dryland areas. However, no field-based data are available describing turbulent airflow dynamics in the wake of vegetation patches. In this study, turbulent wind flow was examined using high-frequency (10 Hz) sonic anemometry at four measurement heights (0.30 m, 0.55 m, 1.10 m and 1.65 m) along a transect in the lee of an extensive patch of shrubs (z = 1.10 m height) in Namibia. Spatial variations in mean wind velocity, horizontal Reynolds stresses and coherent turbulent structures were analysed. We found that wind velocity in the wake of the patch effectively recovered over ∼12 patch heights (h) downwind, which is 2–5 h longer than previously reported recovery lengths for individual vegetation elements and two-dimensional wind fences. This longer recovery can be attributed to a lack of flow moving around the obstacle in the patch case. The step-change in roughness between the patch canopy and the bare surface in its wake resulted in an initial peak in resultant horizontal shear stress ( τ r ) followed by significant decrease downwind. In contrast to τ r , horizontal normal Reynolds stress ( u ′ 2 ‾ ) progressively increased along the patch wake. A separation of the upper shear layer at the leeside edge of the patch was observed, and a convergence of τ r curves implies the formation of a constant stress layer by ∼20 h downwind. The use of τ r at multiple heights is found to be a useful tool for identifying flow equilibration in complex aerodynamic regimes. Quadrant analysis revealed elevated frequencies of Q2 (ejection) and Q4 (sweep) events in the immediate lee of the patch, which contributed to the observed high levels of shear stress. The increasing downwind contribution of Q1 (outward interaction) events, which coincides with greater u ′ 2 ‾ and wind velocity, suggests that sediment transport potential increases with greater distance from the patch edge. Determining realistic, field-derived constraints on turbulent airflow dynamics in the wakes of vegetation patches is crucial for accurately parameterising sediment transport potential in larger-scale dryland landscape models. This will help to improve our understanding of how semi-vegetated desert surfaces might react to future environmental and anthropogenic stresses.

Fluid mechanical dispersion of airborne pollutants inside urban street canyons subjecting to multi-component ventilation and unstable thermal stratifications

The pedestrian level pollutant transport in street canyons with multiple aspect ratios (H/W) is numerically investigated in the present work, regarding of various unstable thermal stratification scenarios and plain surrounding. Non-isothermal turbulent wind flow, temperature field and pollutant spread within and above the street canyons are solved by the realizable k-ε turbulence model along with the enhanced wall treatment. One-vortex flow regime is observed for shallow canyons with H/W=0.5, whereas multi-vortex flow regime is observed for deep canyons with H/W=2.0. Both one-vortex and multi-vortex regimes could be observed for the street canyons with H/W=1.0, where the secondary vortex could be initiated by the flow separation and intensified by unstable thermal stratification. Air exchange rate (AER) and pollutant retention time are adopted to respectively evaluate the street canyon ventilation and pollutant removal performance. A second-order polynomial functional relationship is established between AER and Richardson number (Ri). Similar functional relationship could be established between retention time and Ri, and it is only valid for canyons with one-vortex flow regime. In addition, retention time could be prolonged abruptly for canyons with multi-vortex flow regime. Very weak secondary vortex is presented at the ground level of deep canyons with mild stratification, where pollutants are highly accumulated. However, with the decrease of Ri, pollutant concentration adjacent to the ground reduces accordingly. Present research could be applied to guide the urban design and city planning for enhancing pedestrian environment.

The Influence of the Wind Flow Around the Free Ends of High-Rise Building on the Values of External Wind Pressure Coefficients

The external wind pressure coefficients are based on the measurements on the structures without free-end flow near the top of vertical structures. The end-effect factor takes into account reduction of the pressures due to specific flow around the top of atypical building. The article is based on the experimental measurements in BLWT tunnel in Bratislava on the model of building with cross section of the quarter circle. The model was tested in two spaces - in steady and turbulent wind flow, by changing of wind direction and wind velocity. The end-effect factor depending on the wind direction is shown in the graphs.

Characterizing turbulent wind flow around dryland vegetation

AbstractWind flow has been studied in situations where it encounters porous and solid windbreaks, but there has been a lack of research exploring turbulent wind dynamics around and in the lee of real vegetation elements. In dryland contexts, sparse vegetation plays an important role in modulating both the erosivity of the wind and the erodibility of surfaces. Therefore, understanding the interactions between wind and vegetation is key for improving wind erosion modelling in desert landscapes. In this study, turbulent wind flow around three typical dryland vegetation elements (a grass clump, a shrub, and a tree) was examined in Namibia using high‐frequency (10 Hz) sonic anemometry. Spatial variations in mean wind velocity, as well as Reynolds stresses and coherent turbulent structures in the flow, were compared and related to the porosities and configurations of the study elements. A shelter parameter, originally proposed by Gandemer (, Journal of Wind Engineering and Industrial Aerodynamic 4: 371–389), was derived to describe the combined impact of the different elements on the energy and variability of horizontal wind flow. Wind velocity was reduced by 70% in the immediate lee of the grass and 40% in the lee of the shrub, but velocity recovered exponentially to equilibrium over the same relative distance in both cases (~9 element heights downwind). Quadrant analysis of the high‐frequency wind flow data revealed that the grass clump induced a small recirculation zone in its lee, whereas the shrub did not. Also, higher Reynolds shear stress and higher ‘flow positivity magnitude’ [ratio of Q1 (outward interaction) and Q4 (sweep) quadrants to Q2 (ejection) and Q3 (inward interaction) quadrants] was generally observed in the wake of the grass. These differences arose because the porosity of the grass clump (53%) was lower than the porosity of the shrub (69%), and thus bleed flow through the shrub was more significant. The bluff‐body behaviour of the grass resulted in a more intense and more extensive sheltering effect than the shrub, which implies that overall sediment transport potential is lower in the wake of the grass. The tree displayed a different wake structure to the grass and shrub, owing to the elevation of its crown. A ‘bottom gap’ effect was observed, whereby wind velocities increased possibly due to streamline compression in the gap between the ground and the underside of the tree crown. Differences in flow momentum between the bottom gap and the low‐pressure leeward region of the crown are a probable explanation for the formation of a large recirculation vortex. The bottom gap effect led to decreased sheltering up to three tree heights downwind, but the surface became increasingly protected by the frontal impact of the crown over a further eight tree heights downwind (~30 m). The extraction of momentum from the air by the tree therefore resulted in a far more extensive sheltering effect compared to the grass and shrub. This study represents an important investigation of the impact of different vegetation types on turbulent wind flow, and results can be integrated as parameterizations into spatial sediment transport models that explore landscape‐scale change on semi‐vegetated desert surfaces. Copyright © 2016 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.

Scale-resolving simulation to predict the updraught regions over buildings for MAV orographic lift soaring

Birds have been observed to soar over ridges, mountains and cliffs to extend their flight duration with minimal energy expenditure. There is an opportunity to replicate this behavior to enhance the flight duration of Micro Aerial Vehicles (MAVs) which operate in urban environments by exploiting the vertical flow component (orographic lift) of flow over buildings. This paper therefore studies the flow field in a representative urban environments to enhance the operational capability of MAV platforms by increasing range and endurance. The feasibility and benefits of employing Computational Fluid Dynamics (CFD) are investigated, to simulate the turbulent wind flow conditions around a building configuration. A three-dimensional, scale-resolving simulation, utilizing a derivative of the Detached Eddy Simulation approach was considered. The atmospheric boundary layer velocity and turbulent intensity profiles were calibrated at the inlet boundary of the computational domain, to replicate nominal operating conditions. Recent validation of the Improved Delayed Detached Eddy Simulation (IDDES) approach has shown excellent agreement for a number of relevant flows. This provided the motivation for the study of a full-scale multi-building configuration, and suggests that the use of high-fidelity turbulence modeling is able to predict updraught regions of buildings in an urban environment.