A comparison of wind tunnel measurements and CFD model simulations - - PowerPoint PPT Presentation

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A comparison of wind tunnel measurements and CFD model simulations - - PowerPoint PPT Presentation

Sep 12, 2022 143 likes •398 views

A comparison of wind tunnel measurements and CFD model simulations for pollutant dispersion at the portal of road tunnel for different wind directions M. Taghavi 1 , B. Carissimo 1 , F. Gourdol 2 , P. Mejean 2 , L. Soulhac 2 , C. Bernagaud 3 , and

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SLIDE 1

A comparison of wind tunnel measurements and CFD model simulations for pollutant dispersion at the portal of road tunnel for different wind directions

  • M. Taghavi1, B. Carissimo1, F. Gourdol2, P. Mejean2,
  • L. Soulhac2, C. Bernagaud3, and J.F. Burkhart3

1 Centre d’Enseignement et de Recherche en Environnement Atmosphérique (CEREA), Paris, France 2 Ecole Central de Lyon, Laboratoire de Mécanique des Fluides et d'Acoustique, Lyon, France 3 Ministère de l'Ecologie, de l'Energie, du Développement Durable et de la Mer, Centre d'Etudes des Tunnels,

Pôle Ventilation et Environnement, Lyon, France

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SLIDE 2

Outline :

  • Context & Objective
  • Measurements campaign
  • Model configuration and input
  • Primary simulation analysis
  • Uncertainty in tunnel exit conditions
  • Final simulation evaluation
  • Conclusion
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SLIDE 3
  • Context
  • Frequent construction of tunnels (increasing)
  • Obstacles (sometimes natural)
  • Urban area (traffic, noise, pollution, …)
  • Objective

Code_Saturne CFD model Evaluation

Context & Objective

  • tunnel

: solution to keep away the increasing traffic from residential areas (especially in urban areas).

  • tunnel portals problems concerning the air quality may arise due to the concentrated

release of polluted air there.

  • important to have suitable tools to assess the dispersion from roadway tunnels for planning

purposes.

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SLIDE 4

Schema of tunnel model in wind tunnel

Measurements campaign

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SLIDE 5

Description of the tunnel

Measurements campaign

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SLIDE 6

Measurement campaign : visualization

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SLIDE 7

Description of the available datasets :

A- two different tunnel geometries : canyon and slope B- different angles of wind / tunnel axis : 0, 30, 60, 90, 120, 150, 180 C- measured parameters : velocity and turbulence (hot wire) concentration and variances (FID)

Measurements campaign

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SLIDE 8

Different wind / tunnel speed ratio U/V

U: tunnel exit speed V: incoming wind reference velocity

Measurements campaign

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SLIDE 9

Number of cell :

X-Y-Z = 68-74-40 (~200000 nodes)

Resolution :

Axe X= from 8.2 mm on tunnel axis to 190.4 mm on the edge Axe Y= constant at 50mm Axe Z= Variable from 6.4mm at the bottom to 263.3mm at the top

Mesh caracteristics

(Orientation = 90 °)

Model configuration and input data

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SLIDE 10

Boundary conditions:

  • Wind, turbulence
  • Concentration

Mesh set up

30, 60,120, 150 (approximate WT geometry) (same mesh) 0, 90, 180 (exact WT geometry) Model configuration and input data

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SLIDE 11

View of tunnel portal

(Orientation = 90 °)

Model configuration and input data

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SLIDE 12

Configuration 0 ° U/V=1

Primary simulation, evaluation

Simulation results Wind tunnel results

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SLIDE 13

Configuration 60 ° U/V=1

Primary simulation, evaluation

Simulation results Wind tunnel results

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SLIDE 14

Configuration 120 ° U/V=1

Primary simulation, evaluation

Simulation results Wind tunnel results

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SLIDE 15

Configuration 120 ° U/V=2

Primary simulation, evaluation

Simulation results Wind tunnel results

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SLIDE 16

Configuration 120 ° U/V=0.25

Primary simulation, evaluation

Simulation results Wind tunnel results

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SLIDE 17

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

  • 250.0
  • 200.0
  • 150.0
  • 100.0
  • 50.0

0.0 50.0 100.0 150.0 200.0 250.0

Cadim Y (mm)

Comparaison Modèle et Mesure pour profil vertical a: configuration:0, x=1550 et Z=50mm (cas: UsurV=1)

Cadim (Model) Cadim (mesure) 0.0 0.1 0.2 0.3 0.4 0.5 0.6

  • 250.0
  • 200.0
  • 150.0
  • 100.0
  • 50.0

0.0 50.0 100.0 150.0 200.0 250.0

Cadim Y (mm)

Comparaison Modèle et Mesure pour profil vertical a: configuration:0, x=1550 et Z=10mm (cas: UsurV=1)

Cadim (Model) Cadim (mesure) 0.0 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.5

  • 250.0
  • 200.0
  • 150.0
  • 100.0
  • 50.0

0.0 50.0 100.0 150.0 200.0 250.0

Cadim Y (mm)

Comparaison Modèle et Mesure pour profil vertical a: configuration:0, x=1000 et Z=35mm (cas: UsurV=1)

Cadim (Model) Cadim (mesure) 0.0 0.1 0.1 0.2 0.2 0.3 0.3 0.4

  • 250.0
  • 200.0
  • 150.0
  • 100.0
  • 50.0

0.0 50.0 100.0 150.0 200.0 250.0

Cadim Y (mm)

Comparaison Modèle et Mesure pour profil vertical a: configuration:0, x=1000 et Z=10mm (cas: UsurV=1)

Cadim (Model) Cadim (mesure)

Detailed horizontal profiles in the canyon (Configuration 0°; U / V=1)

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SLIDE 18
  • 60
  • 40
  • 20

20 40 60 80 100 120 140 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Z (mm) C adim

Comparaison Modèle et Mesure pour profil vertical a: configuration:90, x=0 et y=-1000mm (cas: UsurV=2)

Turb=0.2 Diss=2 Turb=2 Diss=2 Turb=8 Diss=2 Turb=20 Diss=2 Cadim (mesure)

  • 60
  • 40
  • 20

20 40 60 80 100 120 140 0.0 0.2 0.4 0.6 0.8 1.0 1.2

Z (mm) C adim

Comparaison Modèle et Mesure pour profil vertical a: configuration:90, x=0 et y=-500mm (cas: UsurV=2)

Turb=0.2 Diss=2 Turb=2 Diss=2 Turb=8 Diss=2 Turb=20 Diss=2 Cadim (mesure)

  • 60
  • 40
  • 20

20 40 60 80 100 120 140 0.0 0.2 0.4 0.6 0.8 1.0 1.2

Z (mm) C adim

Comparaison Modèle et Mesure pour profil vertical a: configuration:90, x=0 et y=-250mm (cas: UsurV=2)

Turb=0.2 Diss=2 Turb=2 Diss=2 Turb=8 Diss=2 Turb=20 Diss=2 Cadim (mesure)

  • 60
  • 40
  • 20

20 40 60 80 100 120 140 0.0 0.2 0.4 0.6 0.8 1.0 1.2

Z (mm) C adim

Comparaison Modèle et Mesure pour profil vertical a: configuration:90, x=0 et y=-100mm (cas: UsurV=2)

Turb=0.2 Diss=2 Turb=2 Diss=2 Turb=8 Diss=2 Turb=20 Diss=2 Cadim (mesure)

Effect of an increase of turbulence at the portal head

Uncertainty in tunnel exit conditions

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SLIDE 19

Tool recommended : BOOT (Model Validation Kit, http://www.harmo.org/kit )

Statistical model evaluation :

Scatter Plots

Uncertainty

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SLIDE 20
  • fractional bias (FB) 
  • fraction of predictions within a factor of two
  • f observations (FAC2) 
  • the normalized mean square error (NMSE) 
  • the correlation coefficient (R) 
  • the geometric variance (VG) 
  • the geometric mean bias (MG) 

Statistical measures of model/measurements differences :

Uncertainty

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SLIDE 21

Inside the canyon: Inside and outside the canyon (all):

MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000, FB=FBfn-FBfp)

T02D2 0.12 0.695 0.869 -0.268 (FBfn= 0.007, FBfp= 0.274, FB=FBfn-FBfp) T2D2 0.08 0.821 0.953 -0.195 (FBfn= 0.011, FBfp= 0.205, FB=FBfn-FBfp) T2D30 0.08 0.785 0.935 -0.201 (FBfn= 0.011, FBfp= 0.211, FB=FBfn-FBfp) T8D2 0.05 0.833 0.981 -0.127 (FBfn= 0.020, FBfp= 0.146, FB=FBfn-FBfp) T20D2 0.04 0.832 0.981 -0.073 (FBfn= 0.033, FBfp= 0.106, FB=FBfn-FBfp) T20D20 0.04 0.832 0.981 -0.074 (FBfn= 0.033, FBfp= 0.107, FB=FBfn-FBfp) T30D2 0.15 0.760 0.738 0.137 (FBfn= 0.204, FBfp= 0.067, FB=FBfn-FBfp) MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000, FB=FBfn-FBfp)

T02D2 0.22 0.917 0.811 -0.288 (FBfn= 0.017, FBfp= 0.306, FB=FBfn-FBfp) T2D2 0.20 0.904 0.659 -0.229 (FBfn= 0.045, FBfp= 0.274, FB=FBfn-FBfp) T2D30 0.19 0.910 0.672 -0.231 (FBfn= 0.043, FBfp= 0.274, FB=FBfn-FBfp) T8D2 0.21 0.877 0.615 -0.156 (FBfn= 0.082, FBfp= 0.239, FB=FBfn-FBfp) T20D2 0.23 0.857 0.568 -0.096 (FBfn= 0.119, FBfp= 0.215, FB=FBfn-FBfp) T20D20 0.23 0.857 0.568 -0.098 (FBfn= 0.119, FBfp= 0.216, FB=FBfn-FBfp) T30D2 0.41 0.780 0.439 0.058 (FBfn= 0.261, FBfp= 0.203, FB=FBfn-FBfp)

Sensitivity tests

Turbulence and dissipation variation (tunnel head)

(Configuration : 90° Case : U/V= 2)

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SLIDE 22

Turbulence and dissipation variation (tunnel head)

(Configuration : 90° Case : U/V= 2)

Sensitivity tests

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SLIDE 23

Final simulation, evaluation (90° case)

  • ------------------------- Configuration 90° (concentration) ------------------------

U/V=0.25 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.13 0.953 0.833 -0.099 (FBfn= 0.063, FBfp= 0.162)

U/V=0.5 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.28 0.913 0.813 -0.263 (FBfn= 0.040, FBfp= 0.302)

U/V=1 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.21 0.909 0.722 -0.145 (FBfn= 0.068, FBfp= 0.213)

U/V=2 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.20 0.899 0.698 -0.158 (FBfn= 0.070, FBfp= 0.228)
  • ----------------------- Configuration 90° (Vitesse du vent) ------------------------

U/V=0.25 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.15 0.657 0.985 0.269 (FBfn= 0.298, FBfp= 0.029)

U/V=0.5 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.05 0.783 0.984 -0.008 (FBfn= 0.084, FBfp= 0.091)

U/V=1 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.03 0.776 0.984 -0.021 (FBfn= 0.050, FBfp= 0.071)

U/V=2 MODEL NMSE CORR FA2 FB

  • OBS. 0.00 1.000 1.000 0.000 (FBfn= 0.000, FBfp= 0.000)
  • MOD. 0.03 0.939 0.962 -0.083 (FBfn= 0.025, FBfp= 0.108)

Concentration (adim) Velocity U (m/s)

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SLIDE 24
  • Wind tunnel database for the effect of wind direction and magnitude on

dispersion from a tunnel head.

  • Code_Saturne model has been successfully calibrated for modeling tunnel

pollutants dispersion.

  • The conditions at the portal of tunnel are very important. They can

strongly influence pollutants dispersion.

  • Results have shown a large influence of the geometrical configuration
  • Some small negative value and non justified zero value were found in the
  • measurements. They can influence BOOT output and need to be

addressed.

  • The comparison of the calculated concentrations by the Code_Saturne

model versus observed concentration distributions, for different directions and different velocity ratio, illustrate the ability of this type of model model to be used for regulatory purposes

Conclusions :