Atmospheric Boundary Layer Flow Research Articles

Distributed wind measurements with multiple quadrotor unmanned aerial vehicles in the atmospheric boundary layer

Abstract. In this study, a fleet of quadrotor unmanned aerial vehicles (UAVs) is presented as a system to measure the spatial distribution of atmospheric boundary layer flow. The big advantage of this approach is that multiple and flexible measurement points in space can be sampled synchronously. The algorithm to obtain horizontal wind speed and direction is designed for hovering flight phases and is based on the principle of aerodynamic drag and the related quadrotor dynamics. During the FESST@MOL campaign at the boundary layer field site (Grenzschichtmessfeld, GM) Falkenberg of the Lindenberg Meteorological Observatory – Richard Assmann Observatory (MOL-RAO), 76 calibration and validation flights were performed. The 99 m tower equipped with cup and sonic anemometers at the site is used as the reference for the calibration of the wind measurements. The validation with an independent dataset against the tower anemometers reveals that an average accuracy of σrms<0.3 m s−1 for the wind speed and σrms,ψ<8∘ for the wind direction was achieved. Furthermore, we compare the spatial distribution of wind measurements with the fleet of quadrotors to the tower vertical profiles and Doppler wind lidar scans. We show that the observed shear in the vertical profiles matches well with the tower and the fluctuations on short timescales agree between the systems. Flow structures that appear in the time series of a line-of-sight measurement and a two-dimensional vertical scan of the lidar can be observed with the fleet of quadrotors and are even sampled with a higher resolution than the deployed lidar can provide.

Large-Eddy Simulations of Stability-Varying Atmospheric Boundary Layer Flow over Isolated Buildings

AbstractThis study explores the response of flow around isolated cuboid buildings to variations in the incoming turbulence arising from changes in atmospheric boundary layer (ABL) stability using a building-resolving large-eddy simulation (LES) technique with explicit representation of building effects through an immersed body force method. An extensive suite of LES for a neutral ABL with different model resolution and advection scheme configurations reveals that at least 6, 12, and 24 grid points per building side are required in order to resolve building-induced vortex shedding, mean-flow features, and turbulence statistics, respectively, with an advection scheme of a minimum of third order. Using model resolutions that meet this requirement, 21 building-resolving simulations are performed under varying atmospheric stability conditions, from weakly stable to convective ABLs, and for different building sizes (H), resulting inLABL/H≈ 0.1–10, whereLABLis the integral length scale of the incoming ABL turbulence. The building-induced flow features observed in the canonical neutral ABL simulation, e.g., the upstream horseshoe vortex and the downstream arch vortex, gradually weaken with increasing surface-driven convective instability due to the enhancement of background turbulent mixing. As a result, two local turbulence kinetic energy peaks on the lateral side of the building in nonconvective cases are merged into a single peak in strong convective cases. By considering the ABL turbulence scale and building size altogether, it is shown that the building impact decreases with increasingLABL/H, as coherent turbulent structures in the ABL become more dominant over a building-induced flow response forLABL/H> 1.

On the suitability of second-order accurate finite-volume solvers for the simulation of atmospheric boundary layer flow

Abstract. The present work analyzes the quality and reliability of an important class of general-purpose, second-order accurate finite-volume (FV) solvers for the large-eddy simulation of a neutrally stratified atmospheric boundary layer (ABL) flow. The analysis is carried out within the OpenFOAM® framework, which is based on a colocated grid arrangement. A series of open-channel flow simulations are carried out using a static Smagorinsky model for subgrid scale momentum fluxes in combination with an algebraic equilibrium wall-layer model. The sensitivity of the solution to variations in numerical parameters such as grid resolution (up to 1603 control volumes), numerical solvers, and interpolation schemes for the discretization of nonlinear terms is evaluated and results are contrasted against those from a well-established mixed pseudospectral–finite-difference code. Considered flow statistics include mean streamwise velocity, resolved Reynolds stresses, velocity skewness and kurtosis, velocity spectra, and two-point autocorrelations. A quadrant analysis along with the examination of the conditionally averaged flow field are performed to investigate the mechanisms responsible for momentum transfer in the flow. It is found that at the selected grid resolutions, the considered class of FV-based solvers yields a poorly correlated flow field and is not able to accurately capture the dominant mechanisms responsible for momentum transport in the ABL. Specifically, the predicted flow field lacks the well-known sweep and ejection pairs organized side by side along the cross-stream direction, which are representative of a streamwise roll mode. This is especially true when using linear interpolation schemes for the discretization of nonlinear terms. This shortcoming leads to a misprediction of flow statistics that are relevant for ABL flow applications and to an enhanced sensitivity of the solution to variations in grid resolution, thus calling for future research aimed at reducing the impact of modeling and discretization errors.

A divergence-free inflow turbulence generator using spectral representation method for large-eddy simulation of ABL flows

The generation of inflow turbulence is the first necessary step to conduct a successful large-eddy simulation (LES) of atmospheric boundary layer (ABL) flows. It is required that the generated inflow turbulence is divergence-free and satisfies essential target statistical properties, including the two-point statistics of the flow described by the coherency function and the spatial correlation. In this paper, a computationally efficient synthetic inflow turbulence generation technique with explicitly defined two-point flow statistics is proposed based on the spectral representation method. The divergence-free condition is imposed on the generated turbulence through a posteriori procedure embedded in the Pressure-Implicit with Splitting of Operators (PISO) solver of OpenFOAM. The efficacy of the proposed method to represent one-point and two-point statistics is demonstrated by comparing the generated turbulence with wind field measurements taken at the Boundary Layer Wind Tunnel Laboratory of Western University. The proposed method is then applied to LES of ABL flows for three exposure conditions, and the wind profiles downstream of the inlet are examined. The mean velocity, turbulence intensity, integral length scale profiles, and the velocity spectra are in good agreement with the target experimental data, thus, indicating the potential of the method for computational wind engineering applications such as wind load evaluation studies. The implementation of the proposed method is available at https://github.com/GBitsuamlak/DFSR.

ProLB: A Lattice Boltzmann Solver of Large‐Eddy Simulation for Atmospheric Boundary Layer Flows

AbstractA large‐eddy simulation tool is developed for simulating the dynamics of atmospheric boundary layers (ABLs) using lattice Boltzmann method (LBM), which is an alternative approach for computational fluid dynamics and proved to be very well suited for the simulation of low‐Mach flows. The equations of motion are coupled with the global complex physical models considering the coupling among several mechanisms, namely basic hydro‐thermodynamics and body forces related to stratification, Coriolis force, canopy effects, humidity transport, and condensation. Mass and momentum equations are recovered by an efficient streaming, collision, and forcing process within the framework of LBM while the governing equations of temperature, liquid, and vapor water fraction are solved using a finite volume method. The implementation of wall models for ABL, subgrid models, and interaction terms related to multiphysic phenomena (e.g., stratification, condensation) is described, implemented, and assessed in this study. An immersed boundary approach is used to handle flows in complex configurations, with application to flows in realistic urban areas. Applications to both wind engineering and atmospheric pollutant dispersion are illustrated.

Wire mesh fences for manipulation of turbulence energy spectrum

Manipulation of turbulence within an atmospheric boundary layer flow by application of woven wire mesh fences is investigated. Turbulence properties behind fences of different porosities and mesh opening widths were determined from velocity measurements in a wind tunnel. It is found that with the application of a fence with a porosity of 0.46, the streamwise turbulence intensity can be reduced from the inflow level of 12.5%–8.8% and the integral length scale can be reduced from 380 to 270 mm. The results show that behind the mesh fences turbulence kinetic energy decays as a power law function of the downstream distance for all wire mesh fences tested in the wind tunnel. The decay rate of turbulence kinetic energy is faster, and a larger reduction in the integral length scale is achieved for fences with porosities between 0.46 and 0.64 compared to higher porosities of between 0.73 and 0.75. Porosity of the woven wire meshes is found to be the key parameter which influences their turbulence reduction performance. In the end, application of the wire mesh fences for reduction of wind loads on solar panels and heliostats is discussed. Evaluation of wind loads based on the reduction of turbulence intensity and integral length scale shows that up to 48% and 53% reduction in peak drag and lift forces on a heliostat, respectively, can be achieved with application of mesh fences.

Numerical Modelling of Neutral Atmospheric Boundary Layer Flow Through Heterogeneous Forest Canopies in Complex Terrain (A Case Study of a Swedish Wind Farm)

This paper exposes the risk of generalization of wind conditions from a single met-mast measurement to be representative of the actual flow field in a wind farm situated in complex terrain. The Large-Eddy Simulation of the neutral atmospheric flow for a mid-western Sweden wind farm is performed. The site-specific complex topography and the forest properties are extracted from the Airborne Laser Scanning data. To emphasize the impact of the local topography and surface roughness on the wind field, the wind turbines are not included in the numerical simulations. The predicted wind speeds are compared with the nacelle-mounted anemometers taken from the wind farm's turbine SCADA data where a sufficient degree of match is observed. The results show that mean wind speed, shear exponent and turbulence intensity vary at each wind turbine location justifying the need for turbine-specific assessment of the wind resource in a wind farm located in forested complex terrain. The inter-turbine difference in wind resource is quantified in terms of the difference in turbine-specific mechanical loads. The results show that not only inter-turbine loads varying significantly in the wind farm, but the turbine loads also differ significantly if a homogeneous assumption is made for the forest.

Towards prediction of wind load on pylons for a neutral atmospheric boundary layer flow over two successive hills

In strong wind situations for a neutral atmospheric boundary layers, wind loads on pylons depend on both the mean velocity and the turbulence fluctuations, predicted by analytical models only for simple topographies. For complex topographies, only experiments or numerical simulations give access to the local flow conditions around the pylon. We present experimental and numerical results using a RANS model for the parametric study of the flow near two successive hills of height H and width L for varying distance λ between the tops. We focus on the modification of flow conditions on the second hill by the presence of the first hill. For λ/H≥19.2, the first hill does not modify the flow structure around the second hill. For decreasing values of λ/H below 19.2, a secondary turbulence intensity peak appears on the frontal part of the second hill. It is associated with the impact of the mixing layer generated at the top of the first hill, whose development is well described by analytical models of the planar mixing layer. These analytical models yields simple estimations of the turbulent kinetic energy k for the pylon’s wind load calculations. Different hill slopes and height ratios are also investigated.

Reynolds number effects on the wind pressure distribution on spherical storage tanks

Spherical storage tanks are important industrial equipment with typical bluff body shape, the aerodynamic loads of which are significantly affected by the Reynolds number (Re). In the present research, wind tunnel tests are carried out on spherical storage tanks with 4–20 supporting columns and a range of surface roughness (ks/D ​= ​0, 0.002 and 0.004) under uniform and atmospheric boundary layer (ABL) flows with Re ranging from 105 to 106. The Reynolds number effects on the aerodynamic drag and uplift coefficients, mean and RMS wind pressure distributions are analyzed. The separation angle on the upper hemi-sphere shifts from 135° (super-critical) to 120° (trans-critical) at Re ​≈ ​6.5 ​× ​105 for a smooth tank in the uniform flow. The trans-critical self-modeling Re range criteria are determined by analyzing the similarity of mean and RMS wind pressure coefficient distribution patterns. It is indicated that in the ABL flow, when ks/D ​≥ ​0.002, the mean and RMS wind pressure distribution of a spherical tank in the trans-critical self-modeling Re range can be simulated with merely Re ​> ​2.0 ​× ​105, thus providing a guidance for wind tunnel simulation of sphere-like bodies. Moreover, a piecewise mean wind pressure coefficient model in the trans-critical self-modeling Re range for spherical storage tanks is established for engineering reference.

Scale-adaptive turbulence modeling for LES over complex terrain

The large-eddy simulation (LES) is an efficient method for the study of atmospheric boundary layer (ABL) flow over complex terrain. However, the robustness of LES is influenced by dynamics methods for the subgrid-scale stress, which remains one of the challenging issues. Here, we present a scale-adaptive LES methodology to study ABL flow over complex terrain. We present a canopy stress method for LES over complex terrain, which provides no-slip and shear-stress boundary conditions using a cost-effective Cartesian mesh. We consider measurements from wind tunnel experiments for the investigation of a scale-adaptive subgrid-scale modeling framework for LES of wind flow over a hilly terrain. A flow simulation is then performed on six cases of ABL flow over an idealized complex terrain. The LES result is also compared against the measurement of wind over Askervein hill. The dynamic and non-dynamic versions of the turbulence kinetic energy-based subgrid model are also considered to illustrate the scale-adaptive nature of subgrid-scale turbulence. It was observed that ignoring scale-adaptivity of subgrid turbulence, LES can under-predict shear-stress, turbulence kinetic energy, and other statistical measures of atmospheric turbulence.

Boundary-Layer Flow Over Complex Topography

We review developments in the field of boundary-layer flow over complex topography, focussing on the period from 1970 to the present day. The review follows two parallel strands: the impact of hills on flow in the atmospheric boundary layer and gravity-driven flows on hill slopes initiated by heating or cooling of the surface. For each strand we consider the understanding that has resulted from analytic theory before moving to more realistic numerical computation, initially using turbulence closure models and, more recently, eddy-resolving schemes. Next we review the field experiments and the physical models that have contributed to present understanding in both strands. For the period 1970–2000 with hindsight we can link major advances in theory and modelling to the key papers that announced them, but for the last two decades we have cast the net wider to ensure that we have not missed steps that eventually will be seen as critical. Two important new themes are given prominence in the 2000–2020 period. The first is flow over hills covered with tall plant canopies. The presence of a canopy changes the flow in important ways both when the flow is nearly neutral and also when it is stably stratified, forming a link between our two main strands. The second is the use of eddy-resolving models as vehicles to bring together hill flows and gravity-driven flows in a unified description of complex terrain meteorology.

Large-eddy simulation of turbulent flows over an urban building array with the ABLE-LBM and comparison with 3D MRI observed data sets

In this article we describe the details of an ABLE-LBM (Atmospheric Boundary Layer Environment-Lattice Boltzmann Model) validation study for urban building array turbulent flow simulations. The ABLE-LBM large-eddy simulation results were compared with a set of 3D magnetic resonance image (MRI) velocimetry data. The ABLE-LBM simulations used the same building layout and Reynolds numbers operated in the laboratory water channel. The building set-up was an evenly spaced orthogonal array of cubic buildings (height = H) with a central tall building (height = 3H) in the second row. Two building orientations, angled with 0°and 45° wind directions, were simulated with ABLE-LBM. The model produced horizontal and vertical fields of time-averaged velocity fields and compared well with the experimental results. The model also produced urban canyon flows and vortices at front and lee sides and over building tops that were similar in strength and location to the laboratory studies. The turbulent kinetic energy associated with these two wind directions were also presented in this simulation study. It is shown that the building array arrangement, especially the tall building, has a great effect on turbulent wind fields. There is a Karman vortex street on the lee side of the tall building. High turbulent intensity areas are associated with the vortex shedding motions at building edges. In addition, the wind direction is a very important factor for turbulent wind and kinetic energy distribution. This validation study indicated that ABLE-LBM is a viable simulation model for turbulent atmospheric boundary layer flows in the urban building array. The computational speed of ABLE-LBM using the GPU has shown that real-time LES simulation is realizable for a computational domain with several millions grid points.

Longitudinal coherence and short-term wind speed prediction based on a nacelle-mounted Doppler lidar

The spatial structure of turbulence in atmospheric boundary layer flows is highly relevant to wind energy. In particular, wind turbine control strategies based on inflow preview measurements require knowledge of the longitudinal evolution of turbulent flow as it approaches the rotor. These upstream measurements are usually obtained with nacelle-mounted wind lidars. In contrast to traditional in situ anemometry, lidars collect measurements within a probe volume which varies in size depending on the technology of the commercial system being used. Here, we address two issues related to the use of wind lidar to measure the incoming flow to a wind turbine: (i) whether existing longitudinal coherence models can be used to predict flow at the rotor, based on measurements performed at a distance away from the rotor; and (ii) what effect probe-volume averaging has on the inflow predictions. These two questions are critical to the design and implementation of robust wind turbine control strategies. To address these questions, we perform field measurements and large-eddy simulations to determine which incoming flow structures can be readily predicted with existing coherence models, and which require additional corrections to account for lidar volumetric averaging effects. Results reveal that the wind turbine induction zone has a negligible impact on the longitudinal coherence and first-order turbulence quantities, such as the standard deviation of velocity fluctuations. However, the phase of the signal, from which advection time periods of the turbulent structures are derived, is affected by the rotor blockage effect.

Long-range Doppler lidar measurements of wind turbine wakes and their interaction with turbulent atmospheric boundary-layer flow at Perdigao 2017

As part of the Perdigão 2017 campaign, vertical RHI (range-height indicator) scans with long-range pulsed Doppler wind lidars were performed aligned with the main wind direction and a wind turbine (WT) located on a mountain ridge. The measurements are used to not only retrieve flow velocities, but also their variance and - by using the turbulent broadening of the Doppler spectrum - also turbulent kinetic energy (TKE) dissipation rate. The study shows that turbulence in the WT wake is dependent on the turbulence of the inflow, but also on atmospheric stability. In stable atmospheric conditions, wakes could be analyzed up to five rotor diameters downstream (D) and showed the maximum turbulence in the wake at 2-3 D, whereas in unstable conditions, the maximum was found at 2 D and the wake could not be detected further than 3 D. A clear dependency of wake turbulence enhancement on inflow turbulence intensity is found, which levels out to no further enhancement at turbulence intensities of 30%.

Structure Functions and Structure Parameters of Velocity Fluctuations in Numerically Simulated Atmospheric Convective Boundary Layer Flows

AbstractWe extend our previous study, which dealt with structure functions of potential temperature fluctuations, and focus on the characteristics of second-order velocity structure functions and corresponding structure parameters in the atmospheric convective boundary layer. We consider the three previously reported methods to compute the structure parameters of turbulent velocity fields: the direct method, the true spectral method, and the approximate spectral method. The methods are evaluated using high-resolution gridded numerical data from large-eddy simulations of shear-free and shear-driven convective boundary layers. Results indicate that the direct and true spectral methods are more suitable than the approximate spectral method, which overestimates the structure parameters of velocity as a result of assuming the inertial-subrange shape of the velocity spectrum for all turbulence scales. Results also suggest that structure parameters of vertical velocity fluctuations are of limited utility because of violations of local isotropy, especially in shear-free convective boundary layers.

Surface Thermal Heterogeneities and the Atmospheric Boundary Layer: The Thermal Heterogeneity Parameter

Representing land–atmosphere exchange processes at the ground surface of numerical-weather-prediction models remains a challenge in spite of the recent advances in computing. Previous studies investigating the effects of spatial surface heterogeneities have been viewed from a turbulence perspective, mostly assuming the existence of a blending length scale above which surface-induced perturbations are modelled using an ad hoc bulk surface parameter representing a pseudo-equivalent surface condition. While these types of approaches can generate reasonable results, they fail to account for the long-lasting spatial perturbations that modify the mean flow. In this work, the interactions between the characteristic scales of surface thermal heterogeneities and the mean resolved fluid dynamics are investigated for a broad range of unstable atmospheric conditions. Thermal dispersive fluxes, which naturally appear as a means to account for persistent-in-time advection fluxes generated by unresolved spatial heterogeneities, provide a quantification of the interaction between surface thermal heterogeneities and the atmospheric boundary-layer mean flow. Hence, they also provide a deterministic approach for including the effect of unresolved processes on the mean flow. We introduce a new non-dimensional number (i.e., the heterogeneity parameter) that can be used to identify the flow conditions and surface configurations in which heterogeneity effects become important. The heterogeneity parameter can be used to distinguish cases with high and low dispersive-flux contributions based on the mean flow and characteristics of the thermal heterogeneities. These results suggest that under weak geostrophic forcing, surface heterogeneity effects should be accounted for in numerical-weather-prediction models.

Computational Flow Analysis in Aerospace, Energy and Transportation Technologies with the Variational Multiscale Methods

With the recent advances in the variational multiscale (VMS) methods, computational ow analysis in aerospace, energy, and transportation technologies has reached a high level of sophistication. It is bringing solutions in challenging problems such as the aerodynamics of parachutes, thermo-fluid analysis of ground vehicles and tires, and fluid-structure interaction (FSI) analysis of wind turbines. The computational challenges include complex geometries, moving boundaries and interfaces, FSI, turbulent flows, rotational flows, and large problem sizes. The Residual-Based VMS (RBVMS), Arbitrary Lagrangian-Eulerian VMS (ALE-VMS) and Space-Time VMS (ST-VMS) methods have been successfully serving as core methods in addressing the computational challenges. The core methods are supplemented with special methods targeting specific classes of problems, such as the Slip Interface (SI) method, MultiDomain Method, and the ST-C data compression method. We provide and overview of the core and special methods. We present, as examples of challenging computations performed with these methods, aerodynamic analysis of a ramair parachute, thermo-fluid analysis of a freight truck and its rear set of tires, and aerodynamic and FSI analysis of two back-to-back wind turbines in atmospheric boundary layer flow. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Investigating microclimate effects in an oasis-desert interaction zone

To investigate oasis-desert microclimate effects, we performed a series of numerical simulations in an idealized oasis-desert system based on an improved computational fluid dynamics (CFD) model for simulating atmospheric boundary layer flows, air temperature and humidity. Numerical simulations were designed based on the hydrometeorological observations obtained during the HiWATER-MUSOEXE (Heihe Watershed Allied Telemetry Experimental Research, Multi-Scale Observation Experiment on Evapotranspiration over heterogeneous land surfaces) campaign. The results are summarized as follows: (1) Oasis-desert interactions are significantly affected by background wind conditions. We observed the oasis-desert local circulation under calm background wind conditions and the oasis thermal internal boundary layer under low wind speed conditions induced by hydrothermal contracts. These interactions will disappear when the background wind speed is sufficiently high, and there is only an oasis dynamic internal boundary layer caused by the aerodynamic roughness length contrast. (2) Oasis-desert interactions lead to a series of microclimate effects, including the oasis cold-wet island effect, air humidity inversion effect within the surrounding desert and oasis wind shield effect, which are important for the stability and sustainability of the oases-desert ecosystem. (3) The hydrothermal conditions due to the difference between the oasis and desert, the vegetation fraction and distribution patterns impact the oasis-desert microclimate effects. The intensity of oasis-desert interactions increases with the land surface temperature (LST) difference in the oasis-desert. The oasis-desert interactions are gradually strengthened with the increase of the vegetation fraction within the oasis. Integrated ecological and economic benefits of the oasis, the oasis vegetation pattern, which includes the croplands and shelterbelts staggered within the oasis and the shelterbelts surrounding the outside, is beneficial to limiting the loss of water vapor and preventing sandstorms from the oasis. The findings of the current study improve the fundamental understanding of the microclimate and provide implications for maintaining the sustainability of oasis-desert ecosystems.

Outdoor measurements of relationship between canopy flow and wall pressure distributions of a block within urban-like block array

Research on indoor ventilation is mainly conducted utilizing wind-tunnel experiments and computational fluid dynamics simulations under controlled flow conditions. However, with these techniques, the effects of the actual urban boundary-layer flow with variable wind directions and turbulence on the ventilation performance of a building surrounded by various buildings remain unresolved. Therefore, we conducted outdoor experiments at the Comprehensive Outdoor Scale Model experiment site to evaluate the mutual relationships between wall pressure of a building within a square array, in which cubical blocks are aligned in same spanwise position in a row, and atmospheric urban boundary-layer flow. The dataset consisting of the simultaneous measurements of the wall pressure acting on a target block and the air flow around it was analyzed statistically. The results demonstrate that the distributions of wind pressure coefficient significantly change with the approaching wind direction, while similar cavity flow patterns such as the downward flow at windward wall and the upward flow at leeward wall are observed regardless of the wind direction. Additionally, the pressure coefficient is more sensitive to the approaching wind direction at the side-edge than at the center of the block surface. Moreover, the temporal and spatial distributions of wall pressure are highly correlated with the fluctuating flow above the canopy rather than the turbulence generated within the canopy.

Turbulence characteristics in the wake of a heliostat in an atmospheric boundary layer flow

The mean and spectral characteristics of turbulence in the wake flow of a flat plate model resembling a heliostat in the atmospheric boundary layer flow are investigated in a wind tunnel experiment. Mean velocity and turbulence kinetic energy were characterized in the wake of a heliostat model at three elevation angles up to a distance of eight times the characteristic dimension of the heliostat panel. An increase in turbulence intensity and kinetic energy was found in the wake flow, reaching a peak at a distance equal to approximately twice the characteristic dimension of the heliostat panel. Furthermore, spectral and wavelet analysis of velocity fluctuations in the wake showed that the dominant mechanism in the immediate downstream of the plate was the breakdown of large inflow turbulence structures to smaller scales. In the end, the wake-induced turbulence patterns and wind loads in a heliostat field were discussed. It was found that compared to a heliostat at the front row, the heliostats positioned in high-density regions of a field were subjected to a higher turbulence intensity and, consequently, larger dynamic wind loading. The results show that it is necessary to consider the increased unsteady wind loads for the design of a heliostat in high-density regions of a field, where the gap between the rows is less than three-times the characteristic length of the heliostat panel.