Stedebouwfysica, Wind Engineering, Gebouwschil Building Physics and Systems

Stedebouwfysica, Wind Engineering, Gebouwschil Building Physics and Systems

Stedebouwfysica Een definitie De ingenieursdiscipline die zich richt op de studie van fysische processen in de (buiten-)omgeving van gebouwen, met inbegrip van warmte, vocht, lucht, licht en geluid, met als doel te zorgen voor een gezonde en comfortabele leefomgeving in en rond gebouwen en dit op een duurzame wijze.

Urban Heat Island (UHI) effect in metropolitan Atlanta, May 11-12, 1997 (NASA/Goddard Space Flight Center Scientific Visualization Studio)

Building Physics and Systems

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Hurricane Katrina flooding of New Orleans, August 29, 2005 (dannyordes.com/katrina.html)



Hunting Lodge St. Hubertus, Hogeand Veluwe, Netherlands Building Physics Systems

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Builiding facade moisture damage - Hunting Lodge St. Hubertus, Hoge Veluwe, Netherlands

Briggen PM, Blocken B, Schellen HL. 2009. Wind-driven rain on the facade of a monumental tower: numerical simulation, full-scale validation and sensitivity analysis. Building and Environment 44(8): 1675–1690. Building Physics and Systems


Royal Festival Hall, London, UK (White 1967)


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Royal Festival Hall, London, UK (White 1967)



Moscow air pollution (photograph by Alexander Petrenko)


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Stedebouwfysica, Stedebouwfysica, bouwfysica en gebouwschil Onderverdeling van de bouwfysica Bouwfysica van de binnenomgeving

Bouwfysica van de gebouwschil

Bouwfysica van de buitenomgeving


Stedebouwfysica, Stedebouwfysica, bouwfysica en gebouwschil Onderverdeling van de bouwfysica Bouwfysica van de binnenomgeving




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Stedebouwfysica, Stedebouwfysica, bouwfysica en gebouwschil Gekoppelde deeldomeinen Bouwfysica van de binnenomgeving




Gebouwschil en wind engineering Wind Engineering De ingenieursdiscipline die zich richt op de studie van de windstroming, en de eraan verbonden fysische processen, in de atmosferische grenslaag rond en over alle obstakels die erin aanwezig zijn. Wind Engineering is interdisciplinair. Wind-structuur-interactie

Windhinder voor voetgangers

(Dooms, De Roeck, Degrande 2007)

Dispersie van luchtverontreiniging door wind

Slagregen op gebouwgevels


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Gevel en wind Building Physics and Systems

Windhinder / Wind nuisance What? Wind nuisance = nuisance due to increased wind speed near buildings at pedestrian level


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Windhinder / Wind nuisance Why? Building aerodynamics:

Corner streams! Standing vortex! Influencing parameters: - Building dimensions - Wind speed - Wind direction Building Physics and Systems Beranek & Van Koten (1979)


Corner streams! (Standing vortex)


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Corner streams! Standing vortex!


Windhinder / Wind nuisance Why? Building aerodynamics: Building arrangements / configurations


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Windhinder / Wind nuisance

Passage through a building:

pressure short circuiting



Passage between parallel buildings:


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Passage between shifted buildings:


Wind nuisance & building envelope: case study 2002 situation (night)


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Wind nuisance & building envelope: case study 2002 situation (day)


Wind nuisance & building envelope: case study - housing department: architectural contest - contest winning feature of the design: safety aspect * passages through the towers: social control (through sight) * pedestrian walk-ways are introduced that lead through the towers * entrances are situated in the passages Tower 1 Tower 2

pedestrian walk-way

Tower 1 Tower 2 Tower 3

Tower 3

N passages Apartment building House blocks Building Physics and Systems

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Wind nuisance & building envelope: case study - housing department: architectural contest - contest winning feature of the design: safety aspect * passages through the towers: social control (through sight) * pedestrian walk-ways are introduced that lead through the towers * entrances are situated in the passages pedestrian walk-way


N

upper passage

passages 4.2 m

5m 3m

0.4 m

lower passage

building entrances


Wind nuisance & building envelope: case study - through-passages are the most important feature - high wind speed in the passage might occur - a favourable wind climate is imperative

pedestrian walk-way


N

upper passage

passages 4.2 m

5m 3m

0.4 m

lower passage

building entrances


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Wind nuisance & building envelope: case study - evaluate local wind climate in the passages - if needed, suggest modifications

Tower 1

pedestrian walk-way

Tower 2 Tower 3

N

upper passage

passages 4.2 m

5m

0.4 m

3m

lower passage

building entrances


Wind nuisance & building envelope: case study CFD simulations: Model validation based on wind tunnel measurements (Wiren 1975)

H

b h

B

L

H = 18 m, L = 80 m

x

1.6

U0

b = 4 m (num)

1.4

b = 6 m (num) U/Uo (-)

α

b = 8 m (num)

1.2

b = 4 m (exp) b = 6 m (exp)

1.0

b = 8 m (exp)

0.8 0


2

4

6

8

10

12

passage length co-ordinate x (m)

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Wind nuisance & building envelope: case study CFD simulations: Model validation based on wind tunnel measurements (Beranek 1982)


Wind nuisance & building envelope: case study CFD simulations: Model validation based on wind tunnel measurements (Beranek 1982)


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Wind nuisance & building envelope: case study CFD simulations: Model geometry Tower 1 Tower 2 Tower 3

N passages


Wind nuisance & building envelope: case study CFD simulations: Model in computational domain


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Wind nuisance & building envelope: case study CFD simulations: Computational mesh on the surfaces of the building models


Wind nuisance & building envelope: case study CFD simulations: Simulation results For Θ = 30°(from north)

a

Tower 1

Tower 2

Tower 3

Wind flow

North


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Wind nuisance & building envelope: case study CFD simulations: Simulation results

TOREN 1

N 0° 4 330°

30° 3

300°

60°

2 1

W 270°

0

O 90°

240°

210°

For Θ = 30°(from north)

a

120°

150° Z 180°

Tower 1

b

Tower 2 Tower 3

Wind flow

additional overpressure generated due to local configuration

North


Wind nuisance & building envelope: case study Wind comfort assessment: 1. meteorological information 2. aerodynamic data to link Umet to U0 and U0 to U 3. comfort criterion at the location of interest (the passage)

U + σu Pmax

< 6 m/s

= 15%

γ = U/U0 building site

meteorological station Umet

U0

U


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Wind nuisance & building envelope: case study Discomfort probability Pmax (should be smaller than 15%) Tower 1 Tower 2

Pmax =

Tower 3

Tower 1: 49% Tower 2: 55% Tower 3: 43%

N passages

Wind climate is extremely uncomfortable and must be improved! Building Physics and Systems

Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Possible solutions: 1. Permanent closure of the passages

+ Building Physics and Systems

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Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Possible solutions: 1. Permanent closure of the passages 2. Reducing the pressure difference: tubes extending the passage

+

-


Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Possible solutions: 1. Permanent closure of the passages 2. Reducing the pressure difference: tubes extending the passage 3. Increase flow resistance: screens in the passages

+

-


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Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Possible solutions: 1. Permanent closure of the passages 2. Reducing the pressure difference: tubes extending the passage 3. Increase flow resistance: screens in the passages 4. Revolving door in the passages

+

-


Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Possible solutions: 5. Sliding doors

+

-


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Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Selected solution: - Sliding doors at both ends of the passage - Opening and closing of the door: based on local wind speed measurements If the wind speed discomfort threshold is exceeded, at least one of the doors must be closed → wind climate is OK - Double control system: 1. automatic control system that registers wind speed and closes one of the doors when threshold is exceeded. 2. manual control system for pedestrians to open one door while the other must be closed.

upper passage 4.2 m

5m

0.4 m

3m

lower passage

building entrances


Wind nuisance & building envelope: case study Problem: pressure short-circuiting between windward and leeward facade Selected solution: - Measurement of wind speed: in the upper passage * limited distance between all control system components * Correlation between wind speed in upper and lower passage Correlation is not exact! → can be calculated with CFD TOREN Tower 11

N 0° 4 330°

30° 3

300°

60°

2 1

W 270°

0

E 90°

upper passage 240°

120° 210°

150°

4.2 m

5m 3m

0.4 m

lower passage

S 180°

lower

Building Physics and Systems upper(s.d.opened)

building entrances

upper(s.d.closed)

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Wind nuisance & building envelope: case study Implementation:




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Gevel en regen Building Physics and Systems

WindWind-driven rain on building facades

Raindrop trajectories


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WindWind-driven rain on building facades Hunting Lodge St. Hubertus


WindWind-driven rain on building facades Building facade deterioration


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WindWind-driven rain on building facades CFD simulations

(Briggen et al. 2009)


WindWind-driven rain on building facades Measurements


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WindWind-driven rain on building facades - CFD simulations: - Steady RANS - Realizable k-εε model (Shih et al. 1995) - Standard wall functions (Launder and Spalding 1974) with roughness modification based on equivalent sand-grain roughness parameters (Cebeci and Bradshaw 1977) - Pressure-velocity coupling: SIMPLE - Second order pressure interpolation - Second order discretisation schemes - Fluent 6.2 commercial code - Hybrid grid based on grid-sensitivity analysis: 6.5 x 105 cells


WindWind-driven rain on building facades Validation of CFD simulations Mixed image: Good agreement for top part Very poor agreement for bottom part

Catch ratio

(Briggen et al. 2009) Building Physics and Systems

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WindWind-driven rain on building facades Causes for discrepancies Reason: turbulent dispersion of raindrops

(Briggen et al. 2009)


Gevel en regen (2) Building Physics and Systems

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WindWind-driven rain: case study 1. Gebouw Hoofdgebouw KUB (Katholieke Universiteit Brussel)

Zicht uit het ZW

Zicht uit het NW


WindWind-driven rain: case study 1. Gebouw

- 3 modules - Hellende spouwmuur - Deelgevel in trapvorm


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Bijkomende informatie: - Constructie: start: 1978, einde: 1981. - 3 modules, 5 verdiepingen - Gevelopbouw: 1.

Beton (190 mm)

2.

Isolatie (45 mm)

3.

Luchtspouw (10 mm)

4.

Baksteen (97 mm)

- Hellende geveldelen: 78.8° - 1 geveldeel in trapvorm Building Physics and Systems

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WindWind-driven rain: case study 2. Problemen 1. Stabiliteitsproblemen (buiging, uitknikken van het buitenspouwblad) 2. Slagregenproblemen (regenpenetratie, gevelvervuiling)


WindWind-driven rain: case study 2. Problemen 1. Stabiliteitsproblemen (buiging, uitknikken van het buitenspouwblad) 2. Slagregenproblemen (regenpenetratie, gevelvervuiling) a) Regenpenetratie


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WindWind-driven rain: case study 2. Problemen 1. Stabiliteitsproblemen (buiging, uitknikken van het buitenspouwblad) 2. Slagregenproblemen (regenpenetratie, gevelvervuiling) a) Regenpenetratie


WindWind-driven rain: case study 2. Problemen 1. Stabiliteitsproblemen (buiging, uitknikken van het buitenspouwblad) 2. Slagregenproblemen (regenpenetratie, gevelvervuiling) a) Regenpenetratie b) Gevelvervuiling - differentiële vervuiling - algen- en boomgroei


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen (regen met wind) 2. Horizontale regenval (regen zonder wind) 3. Hellende wanden 4. Slechte detaillering (dakoversteek, dorpels, raam-wand-overgang)


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD a) Geometrisch gebouwmodel


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD b) Model in het rekendomein


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD c) Rekenraster


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD d) Windveld rond het gebouw


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD d) Windveld rond het gebouw bij zuidenwind


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD d) Windveld rond het gebouw bij zuidenwind


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD d) Windveld rond het gebouw bij zuidwestenwind


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD d) Windveld rond het gebouw bij zuidwestenwind


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD e) Regendruppelbanen - zuidenwind - U10 = 10 m/s - d = 1 mm


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD e) Regendruppelbanen - zuidwestenwind - U10 = 10 m/s - d = 1 mm


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD e) Catch ratio


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD e) Catch ratio - zuidenwind - U10 = 10 m/s - d = 1 mm


WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – numerieke analyse met CFD e) Catch ratio - zuidwestenwind - U10 = 10 m/s - d = 1 mm


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WindWind-driven rain: case study 3. Oorzaken 1. Slagregen – waarnemingen




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WindWind-driven rain: case study 3. Oorzaken 2. Horizontale regenval 3. Hellende (niet-verticale) gevels

NL / VL: 800 mm regen/jaar, mogelijk 400 mm slagregen


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WindWind-driven rain: case study 3. Oorzaken 2. Horizontale regenval 3. Hellende (niet verticale) gevels

- differentiële vervuiling - algen- en plantengroei




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WindWind-driven rain: case study 3. Oorzaken 4. Slechte detaillering – regenafloop (vliesgevel, hydrofobe baksteen) a) Afwezigheid van dakoversteek


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WindWind-driven rain: case study 3. Oorzaken 4. Slechte detaillering – regenafloop (vliesgevel, hydrofobe baksteen) a) Afwezigheid van dakoversteek b) Dorpel


WindWind-driven rain: case study 3. Oorzaken 4. Slechte detaillering – regenafloop (vliesgevel, hydrofobe baksteen) a) Afwezigheid van dakoversteek b) Dorpel c) Raamaansluiting


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WindWind-driven rain: case study 4. Voorgestelde oplossing Problemen van regenpenetratie: 1. Gevel 2. Details Regenwaterafloop 1. Verwijderen van baksteengevel en bekleding met zink 2. Bekleden van de dorpels met zink en adequate detaillering voorzien


WindWind-driven rain: case study 4. Voorgestelde oplossing 1. Verwijderen baksteengevel en vervangen door zink op houtwerk


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WindWind-driven rain: case study 4. Voorgestelde oplossing 2. Gepaste detaillering


WindWind-driven rain: case study 4. Voorgestelde oplossing 2. Gepaste detaillering


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Gevel en luchtkwaliteit Building Physics and Systems

Building envelope and air quality Relation between outdoor and indoor air quality

(after Petersen et al., 2002)

Blocken B, Stathopoulos T, Saathoff P, Wang X. 2008. Numerical evaluation of pollutant dispersion in the built environment: comparisons between models and experiments. Journal of Wind Engineering and Industrial Aerodynamics 96(10-11): 1817-1831. Gousseau P, Blocken B, Stathopoulos T, van Heijst GJF. 2011. CFD simulation of near-field pollutant dispersion on a high-resolution grid: a case study by LES and RANS for a building group in downtown Montreal. Atmospheric Environment 45(2): 428-438.


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Building envelope and air quality Downtown Montreal

Gousseau P, Blocken B, Stathopoulos T, van Heijst GJF. 2011. CFD simulation of near-field pollutant dispersion on a high-resolution grid: a case study by LES and RANS for a building group in downtown Montreal. Atmospheric Environment 45(2): 428-438.


Building envelope and air quality

Stathopoulos T., Lazure L., Saathoff P., Gupta A., 2004. The effect of stack height, stack location and roof-top structures on air intake contamination - A laboratory and full-scale study. IRSST report R-392, Montreal, Canada, 2004. Building Physics and Systems

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Stathopoulos T., Lazure L., Saathoff P., Gupta A., 2004. The effect of stack height, stack location and roof-top structures on air intake contamination - A laboratory and full-scale study. IRSST report R-392, Montreal, Canada, 2004. Building Physics and Systems




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RANS – standard k-ε model

LES – dynamic Smagorinsky model

Predicting flow separation is critical need for high-resolution grids! Gousseau P, Blocken B, Stathopoulos T, van Heijst GJF. 2011. CFD simulation of near-field pollutant dispersion on a high-resolution grid: a case study by LES and RANS for a building group in downtown Montreal. Atmospheric Environment 45(2): 428-438.



RANS – standard k-ε model

LES – dynamic Smagorinsky model

MOVIE


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Conclusions The building envelope is the most essential part of a building. Without a building envelope, there is no building. Increasing the environmental performance of buildings means increasing the environmental performance of the building envelope. Building envelopes determine both the indoor and outdoor environmental quality.


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Conclusions The building envelope is the most essential part of a building. Without a building envelope, there is no building. Increasing the environmental performance of buildings means increasing the environmental performance of the building envelope. Building envelopes determine both the indoor and outdoor environmental quality. CFD simulations, when verified and validated, have become indispensible for the analysis of the performance of present and future building envelopes.


Bedankt voor uw aandacht Bert Blocken [email protected] Unit Building Physics and Systems Faculteit Bouwkunde Special thanks to: - Twan van Hooff (PhD student) - Pierre Gousseau (PhD student)

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Stedebouwfysica, Wind Engineering, Gebouwschil Building Physics and Systems

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