SCIPUFF Capabilities and Application SCIPUFF Capabilities and - - PowerPoint PPT Presentation

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SCIPUFF Capabilities and Application SCIPUFF Capabilities and Application in Hazard Assessment in Hazard Assessment

Ian Sykes Sage Management Sage Management Princeton, NJ

H13-087 HARMO 13 Paris, France 1-4 June, 2010

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Lagrangian Puff Model Lagrangian Puff Model

• Concentration field - collection of overlapping puffs

with Gaussian distributions

• Solve ODE’s for puff moments
• Arbitrary range of scales without numerical grid and
• Arbitrary range of scales without numerical grid and

associated diffusion errors

• Arbitrary time-dependent, spatially inhomogeneous

conditions

• Multiple sources with arbitrary time-dependence

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SCIPUFF Generalized Gaussian SCIPUFF Generalized Gaussian

• Uses full tensor moment representation

– describes shear distortion accurately

• Use turbulence closure to describe diffusion

– relates dispersion directly to velocity statistics – valid over wide range of scales – assumed spectral shape implies time-averaging effects – assumed spectral shape implies time-averaging effects

• consistent with theoretical Taylor (ensemble) and Richardson (relative)

diffusion results

( ) ( ) ( ) ( ) ( ) ( ) i j j i j i ij ik jk k k

x u c x u c u d u dt Q x x

α α α α α α

σ σ σ ′ ′ ′ ′ ′ ′ + ∂ ∂ = + + ∂ ∂

( ) ( ) ( ) 2

;

i j i j i j k k

d Aq x u c Q u u x u c q u u dt

α α α

′ ′ ′ ′ ′ ′ ′ ′ ′ ′ = − = Λ

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• Absolute Dispersion

– for steady homogeneous conditions – hence

SCIPUFF Idealized Solutions SCIPUFF Idealized Solutions

2

1

Aqt

y v c v e Q Aq

− Λ

′ ′ ′ ′ Λ   = −    

2

2 1

L

t yy L L

v t e

τ

σ τ τ

−

    ′ = − −        

• Relative dispersion

– model instantaneous plume/puff scale – use reduced turbulence in diffusivity equation – gives early time t1.5 growth

13

;

c c c

d c q dt

Λ

Λ Λ   = Λ ≤ Λ   Λ  

2 1 3 3 2 c c c

d q y v c Qv A y v c dt Λ Λ     ′ ′ ′ ′ ′ ′ ′ = −     Λ Λ Λ    

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Concentration Fluctuation Variance Concentration Fluctuation Variance

• Closure theory provides model for both ensemble

mean and variance (second-order correlation)

– fluctuations are due to turbulent wind fluctuations – pdf shape assumption (clipped normal) gives probability

• Requires puff overlaps since variance is nonlinear
• Efficient overlap calculations enable other nonlinear

effects

– buoyant jet rise dynamics – dense gas effects – liquid-vapor phase transition and associated thermodynamics – nonlinear reactive chemistry

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Fackrell & Robins (1982) Fackrell & Robins (1982)

100 1000

SCIPUFF Maximum mean data Ground-level data

4 5 6

SCIPUFF

Concentration fluctuation intensity for different source sizes Mean concentration vs downwind distance

0.1 1 10 10 100 1 x/ H CUH2 Q 10 2 4 6 8 1 2 3 4 x/ H ˆ c cm

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Nonlinear SCIPUFF Examples Nonlinear SCIPUFF Examples

Reactive chemistry - ozone formation 2-phase chlorine jet, with flashing thermodynamics and dense effects

Z (m)

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Model Model Features Features

• Adaptive Timesteps

– Puffs use appropriate step based on local criteria

• Adaptive Surface Grids

– Integrated Dosage and Deposition fields – Provides high resolution over wide range of scales – Provides high resolution over wide range of scales

• Puff Splitting

– Split puffs to represent inhomogeneous meteorology – Algorithm conserves all moments

• Puff Merging

– Merge overlapping puffs – Efficient search using adaptive grids and linked lists

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Model Model Evaluation Datasets Evaluation Datasets

• PGT curves
• Relative dispersion

– Weil et al. (1993) – Mikkelsen et al. (1988)

• Lab dispersion and
• EPRI PMV&D

– tall-stack emissions

• CONFLUX

– short range, fluctuations

• Dugway field tests
• Lab dispersion and

fluctuation data

• Buoyant jet rise data
• ANATEX

– Continental-scale field experiment

• Dugway field tests

– short range, instantaneous – relative and absolute dispersion

• Model Data Archive

– includes Prairie Grass and dense gas cases

• ETEX

– Continental scale

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MDA Comparisons MDA Comparisons

ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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ntration (ppm) 10

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Passive Passive Tracer Releases Tracer Releases Dense Gas Dense Gas Releases Releases

Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Predicted Concent Observed Concentration (ppm) 10

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Hazard Assessment Systems Hazard Assessment Systems

• SCIPUFF is the dispersion model component in two

US DoD systems

• HPAC: Hazard Prediction and Assessment Capability

– sponsored by Defense Threat Reduction Agency

• JEM: Joint Effects Model

– DoD Program of Record, Joint Program Executive Office CDB – sponsored by JPM IS (Information Systems)

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Hazard Assessment Systems Hazard Assessment Systems

• HPAC and JEM have similar capabilities

– source term models for various incidents

• weapon deployments
• facilities attacks or explosive events

– human effects models

• chemical/biological effects
• nuclear radiation
• global population database
• casualty estimation

– urban dispersion nested models

• building database

– meteorological data servers

• forecast and observations
• global terrain database

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HPAC Sample HPAC Sample