This investigation presents a modelling strategy for wind-energy studies in complex terrains using computational fluid dynamics (CFD). A model, based on an unsteady Reynolds Averaged Navier-Stokes (URANS) approach with modified version of the standard k-ε is applied. validation study Leipzig experiment shows ability model to simulate atmospheric boundary layer characteristics such as Coriolis force and shallow layer. By combining results design experiments (DoE) method, we could determine...

Abstract The airborne measurement platform MASC-3 (Multi-Purpose Airborne Sensor Carrier) is used for measurements over a forested escarpment in the Swabian Alps to evaluate wind field. Data from flight legs between 20 and 200 m above ground on two consecutive days with uphill (westerly) flow September 2018 are analyzed. In lowest 140 speed-up found increased turbulence changes direction directly escarpment, whereas 50 deceleration of measured. Additionally, simulation results numerical...

In wind energy, the accuracy of estimation resource has an enormous effect on expected rate return a project. For given project, assessor is faced with difficult choice wide range simulation tools and workflows varying accuracies (or “skill”) costs. There currently no guideline or process available in industry for helping decision most “optimal” choice—and this particularly challenging mountainous “complex”) terrain. work, new selecting Wind Resource Assessment (WRA) workflow that would...

Abstract. Understanding the uncertainties of Wind Resource Assessments (WRA) is key to reducing project risks, and this particularly challenging in mountainous terrain. In academic literature, many complex flow sites have been investigated, but they all focus on comparing wind speeds from selected directions, do not overall AEP. work, a range simulations are carried out with seven different modelling tools at five terrain results compared speed measurements validation locations. This then...

The furnace of a pulverised coal-fired utility boiler with an electrical output 550 MW, the dimensions 19m x 15m 48m and 32 swirl burners located on four elevations is considered. Coal combustion described by four-step reaction scheme. model covers two heterogeneous reactions for pyrolysis char three gas-phase oxidation volatile matter. A standard k; ε-model used description turbulence. interaction between turbulence chemistry modelled using Eddy Dissipation Concept (EDC). Radiation computed...

A model for the simulation of wind flow in complex terrain is presented based on Reynolds averaged Navier–Stokes (RANS) equations. For description turbulence, standard k-ε, renormalization group (RNG) and a stress turbulence are applied. Additional terms implemented momentum equations to describe stratification Earth’s atmosphere account Coriolis forces driven by rotation, as well drag force due forested canopy. Furthermore, production dissipation added two-equation, models, order capture...

Abstract. The Weather Research and Forecasting (WRF) Model has been coupled with a URANS to simulate the passage of cold front over WINSENT site, wind energy test-site under development. It is located on hill near steep, forested terrain edge. A high spatial resolution necessary flow this complex site accurately for which reason WRF model run at in LES mode an even higher resolution. forest parametrization implemented both models account drag caused by trees. main result that without...

Micrometeorological observations from a tower, an eddy-covariance (EC) station and unmanned aircraft system (UAS) at the WINSENT test-site are used to validate computational fluid dynamics (CFD) model, driven by mesoscale model. The observation site is characterised forested escarpment in complex terrain. A two-day measurement campaign with flow almost perpendicular analysed. first day dominated high wind speeds, while, on second one, calm conditions present. Despite some minor differences,...

Abstract In this paper, new automated processes for applying the commercial Computational Fluid Dynamics (CFD) tools ANSYS Fluent and CFX to wind modelling in complex terrain are developed with goal of decreasing Actual Total Costs (ATC) related planning energy projects. Simulations carried out at site Stotten southern Germany using , ATCs simulations estimated. The simulation set-up post-processing effort identified as having highest effect on ATC, therefore focus reducing these tasks. same...

Abstract. Understanding the uncertainties of wind resource assessments (WRAs) is key to reducing project risks, and this particularly challenging in mountainous terrain. In academic literature, many complex flow sites have been investigated, but they all focus on comparing speeds from selected directions do not overall annual energy production (AEP). work, importance converting speed errors into AEP when evaluating projects highlighted by results seven different WRA workflows at five terrain...

A model for the simulation of wind flow in alpine terrain is presented. The based on Reynolds averaged Navier-Stokes equations using a κ-ε turbulence model. Additional terms are implemented energy equation to describe dry adiabatic cooling atmosphere. orography and flora Earth's surface described by high resolution data from swisstopo. Boundary initial conditions mesoscale COSMO-2 weather MeteoSwiss. Various nestings with different grid resolutions used simulate region between Vaduz...

The furnace of a pulverised coal-fired utility boiler with thermal output 210MW, dimensions 8m x 29m and 12 burners located on three levels, is considered. Coal combustion described by five-step-reaction scheme. model covers two heterogeneous reactions for pyrolysis char gas phase the oxidation volatile matter. A standard k, ε-model used description turbulence. interaction turbulence chemistry modelled using Eddy Dissipation Concept (EDC). transport equations mass, momentum, enthalpy species...

Abstract A model for predicting radiative heal transfer in coal-fired furnaces is presented. The equation modelled by the discrete ordinates method body-fitted coordinates using S4-approximation. gas absorption coefficient determined a weighled-sum-of-grey-gases model, properties of coal and ash particles are derived from specific area mean efficiency factor particle cloud. scattering phase function Delta-Edding-ton approximation. entire radiation adopted vector parallel computers...

Abstract This study aims to develop a concept of passive volumetric flow control system for gas sampling applications onboard fixed-wing UAS based on the pressure field around airfoils. The utilizes aerodynamics create vacuum pump effect that ensures constant sampling, which can be used facilitate airborne aerosol and measurements. is achieved by short-circuiting field’s minima maxima points an airfoil through pipes 3D printed structures could function both as measurement chamber. design...

Abstract The uncrewed airborne measurement platform MASC-3 (Multi-Purpose Airborne Sensor Carrier) is used to measure the influence of a forested escarpment with differing leaf area indices ( LAI ) onto wind field. Data from flight legs between 30 and 200 m above ground uphill (westerly) during summer (July–September) winter (October–March) seasons 2018 2021 are analyzed. Compared low value , it found that mean speed acceleration stronger for high values turbulence enhanced in lee trees...