Urban Microclimate Scale CFD Simulation
2016 CAD-IT ANSYS Convergence - Singapore
Daniel HII Jun Chung
PhD Candidate, Department of Building, School of Design & Environment, NUS
[email protected]
Prof. WONG Nyuk Hien (Supervisor)
[email protected]
26 April 2016
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)
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Introduction: Urban scales
Sketch of the urban boundary layer structure indicating
the various (sub)layers and their names. (Rotach et al.,
2004; modified after Oke, 1987)
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
3D Modeling
Meshing
Solver
Analysis &
Visualization
CEI Ensight
ANSYS Meshing
Autodesk AutoCAD
ANSYS Design Modeler
McNeel Rhinoceros
ANSYS Fluent
ANSYS Icepak
CFD-Post
ANSYS Workbench
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
Coral Secondary School
Site Plan
Class Plan
Class Perspective
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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
Serangoon
Junior College
Site Plan
Class Plan
Class Perspective
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Example 1: Natural ventilation for thermal comfort
North-East Monsoon period
South-West Monsoon period
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Example 2: Housing precinct morphology study
92 cases in total
Cases Distribution Worldwide
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Example 2: Housing precinct morphology study
Guancheng_Shijia, Shenzhen
Spandau, Berlin
Borneo_whale, Amsterdam
Parque_Modelo, Mexico City
n.FAR : 3.03
n.FAR : 3.14
n.FAR : 3.17
n.FAR : 3.35
g.FAR: 2.69
g.FAR: 2.69
g.FAR: 2.25
g.FAR: 2.43
Messina_01, Paris
Skyville_Dawson, Singapore
Bumps, Beijing
Tung_Chung_Crescent, Hong
Kong
n.FAR : 3.42
n.FAR : 3.90
n.FAR : 4.08
n.FAR : 4.08
g.FAR: 2.79
g.FAR: 3.29
g.FAR: 3.36
g.FAR: 3.38
Metro_harbour, Hong Kong
Shininome, Tokyo
Paris_002, Paris
Royal_Peninsula, Hong Kong
Some examples of
housing typologies
n.FAR : 4.65
n.FAR : 5.16
n.FAR : 5.97
n.FAR : 8.09
g.FAR: 3.92
g.FAR: 4.65
g.FAR: 3.99
g.FAR: 6.53
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Example 2: Housing precinct morphology study
N
Original site
N
N
Normalized site
Theoretically homogenous context
A Punggol typology being normalized in the 3X3 setup
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URBAN CASES DATABASE
Example 2: Housing precinct morphology study
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Example 3: Urban heat (anthropogenic)
Roadside measurement equipment
on the 1.2m high tripod
Fluke TiR125 thermal imager
Bus surfaces under thermal imaging
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Roadside measurement at the bus stop in the urban canyon in the afternoon
Example 3: Urban heat (anthropogenic)
50°C at 6m/s (left)
50°C at 6m/s (right)
50°C at 14m/s (left)
50°C at 14m/s (right)
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Example 3: Urban heat (anthropogenic)
Parallel Flow (Plan)
Perpendicular Flow (Plan)
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Example 3: Urban heat (anthropogenic)
Parallel Flow (Left Elevation)
Perpendicular Flow (Left Elevation)
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Example 3: Urban heat (anthropogenic)
Various vehicles in the urban canyon
Example 3: Urban heat (anthropogenic)
North Wind Flow
East Wind Flow
North East Wind Flow
Conclusion
-ANSYS CFD helps to solve design issues in the field of urban design, building and architecture
(thermal comfort, urban morphologies, urban heat island).
What we hope for:
-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.
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)
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CAD-IT Support: Dr. Ma Shengwei
Dr. Lee Yong Jiun
Thank You
[email protected]
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