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 dhjc@u.nus.edu Prof. WONG Nyuk Hien (Supervisor) bdgwnh@nus.edu.sg 26 April 2016
Content Introduction: field, scale, workflow Examples: natural ventilation, morphology, urban heat Conclusion 2
Introduction: Urban physics / environmental wind engineering Link between grand societal challenges and urban physics focus areas. (Blocken, 2015) 3
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) 4
Introduction: ANSYS CFD workflow 3D Modeling Meshing Solver Analysis & Visualization CEI Ensight Autodesk AutoCAD ANSYS Meshing ANSYS Design Modeler McNeel Rhinoceros ANSYS Icepak ANSYS Fluent CFD-Post ANSYS Workbench Turbulence model: RANS Realizable k- ε (Steady & Transient) Energy model: S2S & solar load radiation, gravity (buoyancy) 5
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) 6
Example 1: Natural ventilation for thermal comfort Coral Secondary School Site Plan Class Plan Class Perspective 7
Example 1: Natural ventilation for thermal comfort North-East Monsoon period South-West Monsoon period 8
Example 1: Natural ventilation for thermal comfort Serangoon Junior College Site Plan Class Plan Class Perspective 9
Example 1: Natural ventilation for thermal comfort North-East Monsoon period South-West Monsoon period 10
Example 2: Housing precinct morphology study 92 cases in total Cases Distribution Worldwide 11
Example 2: Housing precinct morphology study Guancheng_Shijia, Shenzhen Spandau, Berlin Borneo_whale, Amsterdam Parque_Modelo, Mexico City n.far : 3.03 g.far: 2.69 n.far : 3.14 g.far: 2.69 n.far : 3.17 g.far: 2.25 n.far : 3.35 g.far: 2.43 Messina_01, Paris Skyville_Dawson, Singapore Bumps, Beijing Tung_Chung_Crescent, Hong Kong n.far : 3.42 g.far: 2.79 n.far : 3.90 g.far: 3.29 n.far : 4.08 g.far: 3.36 n.far : 4.08 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 g.far: 3.92 n.far : 5.16 g.far: 4.65 n.far : 5.97 g.far: 3.99 n.far : 8.09 g.far: 6.53 12
Example 2: Housing precinct morphology study N N N Original site Normalized site A Punggol typology being normalized in the 3X3 setup Theoretically homogenous context 13
URBAN CASES DATABASE
Example 2: Housing precinct morphology study 15
Example 3: Urban heat (anthropogenic) Roadside measurement equipment on the 1.2m high tripod Fluke TiR125 thermal imager Bus surfaces under thermal imaging Roadside measurement at the bus stop in the urban canyon in the afternoon 16
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) 17
Example 3: Urban heat (anthropogenic) Parallel Flow (Plan) Perpendicular Flow (Plan) 18
Example 3: Urban heat (anthropogenic) Parallel Flow (Left Elevation) Perpendicular Flow (Left Elevation) 19
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) 22
CAD-IT Support: Dr. Ma Shengwei Dr. Lee Yong Jiun Thank You dhjc@u.nus.edu 23