Validation Methods of Geometric 3D-CityGML Data for Urban Wind Simulations

Saeedrashed, Younis Saida; Benim, Ali Cemal

doi:10.1051/e3sconf/201912810006

Cited by 4 publications

(3 citation statements)

References 20 publications

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“…Several other software packages that offer some degree of geometry reparation were reviewed by Saeedrashed and Benim (2019). The software packages they analyzed, specifically checking their application for urban wind simulations, were CityDoctor, FreeCAD, GeomagicWrap, MeshLab, NetFabb, and Ansys SpaceClaim.…”

Section: Repairing Existing 3d Buildingmentioning

confidence: 99%

Towards automatic reconstruction of 3D city models tailored for urban flow simulations

Pađen

García‐Sánchez

Ledoux

2022

Front. Built Environ.

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In the computational fluid dynamics simulation workflow, the geometry preparation step is often regarded as a tedious, time-consuming task. Many practitioners consider it one of the main bottlenecks in the simulation process. The more complex the geometry, the longer the necessary work, meaning this issue is amplified for urban flow simulations that cover large areas with complex building geometries. To address the issue of geometry preparation, we propose a workflow for automatically reconstructing simulation-ready 3D city models. The workflow combines 2D geographical datasets (e.g., cadastral data, topographic datasets) and aerial point cloud-based elevation data to reconstruct terrain, buildings, and imprint surface layers like water, low vegetation, and roads. Imprinted surface layers serve as different roughness surfaces for modeling the atmospheric boundary layer. Furthermore, the workflow is capable of automatically defining the influence region and domain size according to best practice guidelines. The resulting geometry aims to be error-free: without gaps, self-intersections, and non-manifold edges. The workflow was implemented into an open-source framework using modern, robust, and state-of-the-art libraries with the intent to be used for further developments. Our approach limits the geometry generation step to the order of hours (including input data retrieval and preparation), producing geometries that can be directly used for computational grid generation without additional preparation. The reconstruction done by the algorithm can last from a few seconds to a few minutes, depending on the size of the input data. We obtained and prepared the input data for our verification study in about 2 hours, while the reconstruction process lasted 1 minute. The unstructured computational meshes we created in an automatic mesh generator show satisfactory quality indicators and the subsequent numerical simulation exhibits good convergence behavior with the grid convergence index of observed variables less than 5%.

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Section: Repairing Existing 3d Buildingmentioning

confidence: 99%

Towards automatic reconstruction of 3D city models tailored for urban flow simulations

Pađen

García‐Sánchez

Ledoux

2022

Front. Built Environ.

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“…Many studies utilize existing digital terrain models (DTMs) of large or major cities [46]. Other projects with more financial resources create their own maps using LIDAR instruments or satellite products [47]. However, it is currently feasible to build digital models of many cities around the world at almost no cost.…”

Section: Meshingmentioning

confidence: 99%

Advances in CFD Modeling of Urban Wind Applied to Aerial Mobility

García-Gutiérrez

Gonzalo

López

et al. 2022

Fluids

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The feasibility, safety, and efficiency of a drone mission in an urban environment are heavily influenced by atmospheric conditions. However, numerical meteorological models cannot cope with fine-grained grids capturing urban geometries; they are typically tuned for best resolutions ranging from 1 to 10 km. To enable urban air mobility, new now-casting techniques are being developed based on different techniques, such as data assimilation, variational analysis, machine-learning algorithms, and time series analysis. Most of these methods require generating an urban wind field database using CFD codes coupled with the mesoscale models. The quality and accuracy of that database determines the accuracy of the now-casting techniques. This review describes the latest advances in CFD simulations applied to urban wind and the alternatives that exist for the coupling with the mesoscale model. First, the distinct turbulence models are introduced, analyzing their advantages and limitations. Secondly, a study of the meshing is introduced, exploring how it has to be adapted to the characteristics of the urban environment. Then, the several alternatives for the definition of the boundary conditions and the interpolation methods for the initial conditions are described. As a key step, the available order reduction methods applicable to the models are presented, so the size and operability of the wind database can be reduced as much as possible. Finally, the data assimilation techniques and the model validation are presented.

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“…Since CityGML allows modeling of so many different structures within a city, it has become a widely used tool by researchers and practitioners, and has been applied to many domains [30]. It has been used in urban planning, such as building energy simulations [31] and wind simulations [32], in disaster management for flood [33] and earthquake simulations [34], and in time series analysis for sustainable lining, among other things. Because CityGML allows the storage and retrieval of 3D data, its use has also been explored for building virtual and augmented reality for navigation applications.…”

Section: Citygml and Ade-apmentioning

confidence: 99%

Personalized accessible wayfinding for people with disabilities through standards and open geospatial platforms in smart cities

Wheeler

Syzdykbayev

Karimi

et al. 2020

Open geospatial data, softw. stand.

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Of the many features that smart cities offer, safe and comfortable mobility of pedestrians within the built environment is of particular importance. Safe and comfortable mobility requires that the built environments of smart cities be accessible to all pedestrians, mobility abled and mobility impaired, given their various mobility needs and preferences. This, coupled with advanced technologies such as wayfinding applications, pedestrians can get assistance in finding the best pathways at different locations and times. Wayfinding applications comprise two components, a database component containing accessibility data, and appropriate algorithms that can utilize accessibility data to meet the mobility needs and preferences of all individuals. While wayfinding applications that provide accessibility on both permanent (e.g., steps) and temporary (e.g., snow) pathways are becoming available, there is a gap in current solutions. There are two elements in the gap, one is that the accessibility data used for finding accessible pathways for people with disabilities are not compliant to the widely agreed upon and available standards, another is that the accessibility data are not available in free and open platforms so that they can be used by developers to develop personalized wayfinding applications and services. To fill this gap, in this paper, we propose a new extension in CityGML with accessibility data. We demonstrate the benefits of the new extension by testing various route options within a city. These route options clearly show the differences between commonly (shortest and fastest) requested and produced pathways and accessible pathways that are feasible and preferred by people who are mobility impaired, such as wheelchair users.

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Validation Methods of Geometric 3D-CityGML Data for Urban Wind Simulations

Cited by 4 publications

References 20 publications

Towards automatic reconstruction of 3D city models tailored for urban flow simulations

Towards automatic reconstruction of 3D city models tailored for urban flow simulations

Advances in CFD Modeling of Urban Wind Applied to Aerial Mobility

Personalized accessible wayfinding for people with disabilities through standards and open geospatial platforms in smart cities

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