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Title [sv]
Stadsventilation
Abstract [sv]
Det övergripande syftet är att skapa en bas för en ny metod, som kan användas av stadsplanerare, för att kunna bedöma luftkvaliteten i städer. Metoden baseras på att hela staden ses som en byggnad bestående av rum utan tak, vilken ventileras av den vind som blåser mot och genom staden. Kvantifiering av ventilationen och bortförsel av föroreningar sker med samma metoder och begrepp som utvecklats för byggnader. Fördelen är a) metoder för kvantifiering av komplicerad strömning med recirkulation som även sker i en stad, kan användas b) ventilation av de enskillda byggnaderna och hela staden är ett kopplat system beroende av varandra och en sammanhållen systemsyn är därför av nytta. Nya metoder för benchmarking baserat på jämt fördelat utsläpp av föroreningar, kommer att utvecklas. Speciellt fokus kommer att ligga på att studera borttransport av föroreningar, vilket sker genom de öppna taken via hastighetsfluktuationer. Syftet är att ta fram beräkningsmetoder som kan använda i relativt enkla modeller. Projektet genomförs av en multidisciplinär forskargrupp med bakgrund i arkitektur, GIS, ventilation och byggnadsteknik. Forskningsmetoderna är; intervjuer, vind tunnel studier, flödessimuleringar samt fältmätningar i en utomhus stadsmodell i Kina, vilken omfattar 3300 byggnader. Effekten av trädplanteringar kommer att studeras i samarbete med forskare från Italien.
Publications (4 of 4) Show all publications
Cehlin, M., Lin, Y., Sandberg, M., Claesson, L. & Wallhagen, M. (2023). Towards benchmarking of urban air quality based on homogenous surface emission. Results in Engineering (RINENG), 20, Article ID 101617.
Open this publication in new window or tab >>Towards benchmarking of urban air quality based on homogenous surface emission
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2023 (English)In: Results in Engineering (RINENG), ISSN 2590-1230, Vol. 20, article id 101617Article in journal (Refereed) Published
Abstract [en]

Here, it is presented a possible methodology and experimental model for benchmarking of air quality in cities. The concept behind the methodology is that a city’s inherent structure affects the potential for contaminant removal due to the resistance it poses to inflow. The approach is based on homogenous emission across the street surface network, representing a worst-case situation. Different levels of complexity can be used for benchmarking, making it valuable for evaluating different layouts. Additionally, an urban ventilation index suitable for these kinds of experimental studies has been suggested. 

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Urban ventilation, City ventilation, Air quality, Wind tunnel, Tracer gas, Experimental model
National Category
Fluid Mechanics and Acoustics
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-43313 (URN)10.1016/j.rineng.2023.101617 (DOI)001127737100001 ()2-s2.0-85178337839 (Scopus ID)
Funder
Swedish Research Council Formas, 2018-00238
Available from: 2023-11-22 Created: 2023-11-22 Last updated: 2024-01-04Bibliographically approved
Lin, Y., Sandberg, M., Cehlin, M., Claesson, L. & Wigö, H. (2022). Evaluation of the Equivalent Purging Flow Rate for Single-side Ventilated Model with Tracer Gas Measurements. In: 5th International Conference on Building Energy and Environment (COBEE 2022): . Paper presented at COBEE 2022, Concordia University, Montreal, Canada, 25-29 July 2022. Springer, Article ID 1419.
Open this publication in new window or tab >>Evaluation of the Equivalent Purging Flow Rate for Single-side Ventilated Model with Tracer Gas Measurements
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2022 (English)In: 5th International Conference on Building Energy and Environment (COBEE 2022), Springer , 2022, article id 1419Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Springer, 2022
Keywords
City ventilation, Compact urban morphology, Wind tunnel experiment, Tracer gas measurement, Single-side ventilation
National Category
Fluid Mechanics and Acoustics
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-39649 (URN)10.1007/978-981-19-9822-5_311 (DOI)2-s2.0-85172730229 (Scopus ID)9789811998218 (ISBN)
Conference
COBEE 2022, Concordia University, Montreal, Canada, 25-29 July 2022
Funder
Swedish Research Council Formas, 2018-00238
Available from: 2022-08-03 Created: 2022-08-03 Last updated: 2023-11-23Bibliographically approved
Buccolieri, R., Lin, Y., Wigö, H. & Sandberg, M. (2021). Drag force rose representing the interaction between urban geometries and wind. In: 15th ROOMVENT (Roomvent 2020) virtual conference: Energy efficient ventilation for healthy future buildings. Paper presented at 15th Roomvent virtual conference, 15-17 February 2021, Turin, Italy (pp. 85-88).
Open this publication in new window or tab >>Drag force rose representing the interaction between urban geometries and wind
2021 (English)In: 15th ROOMVENT (Roomvent 2020) virtual conference: Energy efficient ventilation for healthy future buildings, 2021, p. 85-88Conference paper, Published paper (Refereed)
Abstract [en]

The drag force generated by aligned arrays of cubes of different packing density and exposed to different wind directions in a wind tunnel is discussed. Results allowed to build a drag force rose which shows that the drag force increases with increasing packing density till λp = 0.25 for any wind direction. It is also shown that, independent of the packing density, the drag force increases with increases deviation of WD from the perpendicularity.

Keywords
Drag force rose, Wind tunnel, Cubic building arrays
National Category
Other Mechanical Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-36559 (URN)9788894612301 (ISBN)
Conference
15th Roomvent virtual conference, 15-17 February 2021, Turin, Italy
Funder
Swedish Research Council Formas, 2018-00238
Available from: 2021-06-27 Created: 2021-06-27 Last updated: 2022-12-29Bibliographically approved
Cehlin, M., Ameen, A., Sandberg, M., Claesson, L., Wigö, H. & Lin, Y. (2020). Urban Morphology and City Ventilation. In: : . Paper presented at 10th International Conference on Future Environment and Energy (ICFEE 2020).
Open this publication in new window or tab >>Urban Morphology and City Ventilation
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2020 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The purpose of the paper is to examine the relation between urban morphology, wind direction and air flow rates. In the study a highly idealized city model was used consisting of a circular block divided into two or four equally large sectors. Wind tunnel experiments and CFD predictions have been conducted. The interaction between the atmospheric boundary layer and a city is considered to be both a function of the overall shape and the internal resistance to the flow caused by the friction when the wind flows over the urban surfaces. Flow along the streets is generated by pressure differences. In the wind tunnel, velocity measurements have been recorded in the streets at several points and pressure on the ground was registered in 400 points. The wind tunnel measurements were used to validate the CFD model. The CFD predictions provided complete flow and pressure fields for different configurations and wind directions. The flow balance is presented considering both the horizontal air flow and the vertical air flow (subsidence and updraft). Special attention was on the pressure distribution at ground level (pressure footprint), which is believed to provide valuable information that can be used for qualitative city ventilation analyses. 

Keywords
Urban Morphology, City Ventilation, Crossings
National Category
Fluid Mechanics and Acoustics
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-40631 (URN)
Conference
10th International Conference on Future Environment and Energy (ICFEE 2020)
Funder
Swedish Research Council Formas, 2018-00238
Available from: 2022-12-26 Created: 2022-12-26 Last updated: 2022-12-29Bibliographically approved
Principal InvestigatorCehlin, Mathias
Co-InvestigatorSandberg, Mats
Co-InvestigatorWigö, Hans
Co-InvestigatorJiang, Bin
Co-InvestigatorWallhagen, Marita
Coordinating organisation
University of Gävle
Funder
Period
2018-10-01 - 2021-09-30
National Category
Earth and Related Environmental SciencesCivil Engineering
Identifiers
DiVA, id: project:2232Project, id: 2018-00238_Formas

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