Urban Microclimate Scale CFD SimulationUrban Microclimate Scale CFD Simulation ... ANSYS CFD workflow Autodesk AutoCAD ... -ANSYS CFD helps to solve design issues in the field of urban

Urban Microclimate Scale CFD Simulation

Daniel HII Jun ChungPhD Candidate, Department of Building, School of Design & Environment, NUSdhjc@u.nus.edu

Prof. WONG Nyuk Hien (Supervisor)bdgwnh@nus.edu.sg

26 April 2016

2016 CAD-IT ANSYS Convergence - Singapore

Content

• Introduction: field, scale, workflow

• Examples: natural ventilation, morphology, urban heat

• Conclusion

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Introduction: Urban physics / environmental wind engineering

Link between grand societal challenges and urban physics focus areas. (Blocken, 2015)

Sketch of the urban boundary layer structure indicating the various (sub)layers and their names. (Rotach et al., 2004; modified after Oke, 1987)

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Introduction: Urban scales

Spatial and temporal scales of atmospheric phenomena and how these phenomena are treated in Reynolds-averaged Navier Stokes (RANS) mesoscale or obstacle resolving microscale models (right columns). (Blocken, 2015)

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Introduction: ANSYS CFD workflow

Autodesk AutoCAD

McNeel Rhinoceros

ANSYS Workbench

ANSYS Meshing

ANSYS Icepak

ANSYS FluentCFD-Post

CEI Ensight

ANSYS Design Modeler

Analysis &Visualization3D Modeling SolverMeshing

Turbulence model: RANS Realizable k- ε (Steady & Transient)Energy model: S2S & solar load radiation, gravity (buoyancy)

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Examples

1. Low Density: Educational - secondary school, junior college (thermal comfort)

2. High Density: Residential - high-rise housing (urban morphology)

3. Very High Density: Commercial - Central Business District (urban heat)

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Example 1: Natural ventilation for thermal comfort

Site Plan Class Plan

Class Perspective

Coral Secondary School

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Example 1: Natural ventilation for thermal comfort

North-East Monsoon period South-West Monsoon period

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Example 1: Natural ventilation for thermal comfort

Site Plan Class Plan

Class Perspective

Serangoon Junior College

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Example 1: Natural ventilation for thermal comfort

North-East Monsoon period South-West Monsoon period

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92 cases in total

Cases Distribution Worldwide

Example 2: Housing precinct morphology study

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Guancheng_Shijia, Shenzhen Spandau, Berlin Borneo_whale, Amsterdam Parque_Modelo, Mexico City

n.FAR : 3.03g.FAR: 2.69

n.FAR : 3.14g.FAR: 2.69

n.FAR : 3.17g.FAR: 2.25

n.FAR : 3.35g.FAR: 2.43

Messina_01, Paris Skyville_Dawson, Singapore Bumps, Beijing Tung_Chung_Crescent, Hong Kong

n.FAR : 3.42g.FAR: 2.79

n.FAR : 3.90g.FAR: 3.29

n.FAR : 4.08g.FAR: 3.36

n.FAR : 4.08g.FAR: 3.38

Metro_harbour, Hong Kong Shininome, Tokyo Paris_002, Paris Royal_Peninsula, Hong Kong

n.FAR : 4.65g.FAR: 3.92

n.FAR : 5.16g.FAR: 4.65

n.FAR : 5.97g.FAR: 3.99

n.FAR : 8.09g.FAR: 6.53

Some examples ofhousing typologies

Example 2: Housing precinct morphology study

A Punggol typology being normalized in the 3X3 setup

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N N N

Original site Normalized site

Theoretically homogenous context

Example 2: Housing precinct morphology study

URBAN CASES DATABASE

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Example 2: Housing precinct morphology study

Example 3: Urban heat (anthropogenic)

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Fluke TiR125 thermal imager

Roadside measurement at the bus stop in the urban canyon in the afternoon

Bus surfaces under thermal imagingRoadside measurement equipment

on the 1.2m high tripod

50°C at 14m/s (right)

50°C at 14m/s (left)

50°C at 6m/s (right)

50°C at 6m/s (left)

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Example 3: Urban heat (anthropogenic)

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Parallel Flow (Plan) Perpendicular Flow (Plan)

Example 3: Urban heat (anthropogenic)

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Parallel Flow (Left Elevation) Perpendicular Flow (Left Elevation)

Example 3: Urban heat (anthropogenic)

Example 3: Urban heat (anthropogenic)

Various vehicles in the urban canyon

North East Wind Flow

North Wind FlowEast Wind Flow

Example 3: Urban heat (anthropogenic)

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Conclusion

Schematic representation of the six spatial scales in urban physics, their typical maximum horizontal length scales and associated model categories. NWP = Numerical Weather Prediction; MMM = Mesoscale Meteorological Model; CFD = Computational Fluid Dynamics; BES = Building Energy Simulation; BC-HAM = Building Component e Heat, Air, Moisture transfer; MSM = Material Science Model; HTM = Human Thermophysiology Model. (Blocken, 2015)

-ANSYS CFD helps to solve design issues in the field of urban design, building and architecture(thermal comfort, urban morphologies, urban heat island).

-Better hexahedral + prism meshing for the field.-Availability of built material properties, models (thermal comfort), wizards (wind profile).-Realistic tree models (shading and evapotranspiration). -Better integration with mesoscale (Weather Research Forecasting), microscale (Urban Canopy Model) & building scale (EnergyPlus) simulations.

What we hope for:

Thank You

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dhjc@u.nus.edu

CAD-IT Support: Dr. Ma ShengweiDr. Lee Yong Jiun