SCIPUFF Capabilities and Application SCIPUFF Capabilities and - PowerPoint PPT Presentation

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

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

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 α α ( ) ( ) ′ ′ ′ ′ ′ ′ + x u c x u c ∂ u ∂ d u i j j i j σ α = + σ α + σ α i ( ) ( ) ( ) ij ik jk α ∂ ∂ dt Q x x ( ) k k d Aq α α ( ) ( ) ′ ′ ′ ′ ′ ′ ′ ′ ′ ′ α = − = x u c Q u u x u c q u u ( ) 2 ; i j i j i j k k Λ dt

SCIPUFF Idealized Solutions SCIPUFF Idealized Solutions • Absolute Dispersion ′ ′ ′ y v c ′ Λ  v 2  Aqt − = − – for steady homogeneous conditions e Λ   1 Q Aq       t − ′ σ = τ − τ − τ v t e 2    L  2 1 – hence yy L L     • Relative dispersion 13 Λ Λ d   = Λ ≤ Λ c q c c – model instantaneous plume/puff scale   ; Λ c Λ dt   – use reduced turbulence in diffusivity equation 2 1 Λ Λ d   q   3 3 ′ ′ ′ ′ ′ ′ ′ = − y v c Qv c A c y v c 2     Λ Λ Λ dt     c – gives early time t 1.5 growth

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

Fackrell & Robins (1982) Fackrell & Robins (1982) Concentration fluctuation intensity Mean concentration vs downwind for different source sizes distance 1000 6 SCIPUFF SCIPUFF Maximum mean data 5 Ground-level data 4 4 100 100 c CUH 2 ˆ 3 c m Q 10 2 1 1 0 0.1 1 10 0 2 4 6 8 10 x / H x / H

Nonlinear SCIPUFF Examples Nonlinear SCIPUFF Examples Reactive chemistry - ozone formation 2-phase chlorine jet, with flashing thermodynamics and dense effects Z (m)

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

Model Model Evaluation Datasets Evaluation Datasets • EPRI PMV&D • PGT curves – tall-stack emissions • Relative dispersion • CONFLUX – Weil et al. (1993) – short range, fluctuations – Mikkelsen et al. (1988) • • Dugway field tests Dugway field tests • • Lab dispersion and Lab dispersion and – short range, instantaneous fluctuation data – relative and absolute dispersion • Buoyant jet rise data • Model Data Archive • ANATEX – includes Prairie Grass and dense gas cases – Continental-scale field • ETEX experiment – Continental scale

MDA Comparisons MDA Comparisons Passive Passive Tracer Releases Tracer Releases Dense Gas Dense Gas Releases Releases 3 3 3 3 6 6 6 6 10 10 10 10 10 10 10 10 2 2 2 2 10 10 10 10 ntration (ppm) ntration (ppm) ntration (ppm) ntration (ppm) ntration (ppm) ntration (ppm) ntration (ppm) ntration (ppm) 5 5 5 5 10 10 10 10 1 1 1 1 10 10 10 10 Predicted Concent Predicted Concent Predicted Concent Predicted Concent Predicted Concent Predicted Concent Predicted Concent Predicted Concent 4 4 4 4 10 10 10 10 0 0 0 0 10 10 10 10 3 3 3 3 10 10 10 10 -1 -1 -1 -1 10 10 10 10 -2 -2 -2 -2 2 2 2 2 10 10 10 10 10 10 10 10 -2 -2 -2 -2 -1 -1 -1 -1 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm) Observed Concentration (ppm)

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)

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

HPAC Sample HPAC Sample