Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures. Volume 3. DEGADIS User's Manual
Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures. Volume 3. DEGADIS User's Manual

Author: Jerry A. Havens

Publisher:

Published: 1985

Total Pages: 270

ISBN-13:

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The mathematical modeling techniques used to predict atmospheric dispersion of heavier-than-air gases discussed in Volume 1 are briefly summarized; these techniques are incorporated in an interactive computer model DEGADIS. Details of DEGADIS implementation are briefly discussed. The necessary input information to simulate a heavier-than-air gas release with DEGADIS is summarized. Example simulations of a steady state and transient release are included. A list of DEGADIS self-diagnostics with suggested actions are included. A listing of DEGADIS is included along with a partial list of program variables. Guidelines for installation of DEGADIS are presented.

Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures
Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures

Author: Jerry A. Havens

Publisher:

Published: 1985

Total Pages: 183

ISBN-13:

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Mathematical modeling techniques use to predict atmospheric dispersion of heavy gases are reviewed and critiqued. These dispersion processes are characterized by three phases: (1) near field, negative buoyancy-domainated flow regime; (2) intermediate field, stably stratified shear flow regime; and (3) far field, passive turbulent diffusion regime. Mathematical models of laboratory and natural gravity currents are used to describe the negative buoyancy-dominated regime flow and dilution processes. A laboratory investigation of instantaneous heavy gas releases in calm air demonstrates scaling from small release volumes (0.5 cu m) to large field (2000 cu m) field releases, and is used to develop a mathematical model for the buoyancy-dominated regime. Laboratory data from stratified shear flow mixing experiments are used to develop a model for vertical diffusion of heavy gases in the atmospheric surface layer. The model concepts are consistent with the limiting passive behavior of demonstrated air pollution models. An interactive computer model for heavy gas dispersion (DEGADIS) is developed. The DEGADIS model accounts for the three regimes of heavy gas dispersion processes and can be used to simulate instantaneous, steady state, and transient releases. The model provides predictions of downwind concentration decay which are in good agreement with the full range of field experimental data currently available, and is recommended for incorporation in the Coast Guard hazard assessment computer system.

Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures. Volume 2. Laboratory Calm Air Heavy Gas Dispersion Experiments
Development of an Atmospheric Dispersion Model for Heavier-Than-Air Gas Mixtures. Volume 2. Laboratory Calm Air Heavy Gas Dispersion Experiments

Author: Jerry A. Havens

Publisher:

Published: 1985

Total Pages: 269

ISBN-13:

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Laboratory experimental instantaneous releases of right circular cylindrical volumes of heavy gas (Freon-12/air) with initial volumes ranging from 0.034 cu m to 0.531 cu m and specific gravities ranging from 2.2 to 4.2 are described. Releases with initial height-to-diameter ratios of 0.4, 1.0, and 1.57 are reported. The heavy gas flow field surrounding the release is described by time series of gas concentration at various radial and vertical coordinates with respect to release center. Measurements of the gravity current velocities are determined from time-of-onset of measured gas concentration. Calm-air instantaneous heavy gas releases are demonstrated to scale with a characteristic length cube root of V sub i where V sub i is the initial volume, and a characteristic time (V sub i to the 1/6 power)/(sq root of the reduced gravitational acceleration). The scaled laboratory releases predict the gravity-spreading and dilution process occurring during the buoyancy-dominated flow phase of the 2000 cu/m Freon/air instantaneous releases conducted by the British Health and Safety Executive at Thorney Island, UK. The gravity spread and dilution data are used to validate the buoyancy-dominated flow submodel which is incorporated in DEGADIS, the general purpose heavy gas dispersion model developed for the Coast Guard.

Integrated Regional Risk Assessment, Vol. II
Integrated Regional Risk Assessment, Vol. II

Author: A.V. Gheorghe

Publisher: Springer Science & Business Media

Published: 2013-06-29

Total Pages: 332

ISBN-13: 9401704813

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Over recent years there has been an increasing awareness of the risks of locating hazardous industries near heavily populated, environmentally sensitive areas. This new awareness demands a novel approach to safety planning for hazardous industries; one that looks at the problem from the point of view of integrated regional risk assessment which, besides the risks arising from natural events, should also include the risks arising from the processing plants, storage and the transportation of dangerous goods. Volume I of Integrated Regional Risk Assessment highlights the main procedures for the assessment of risks to health and environmental impacts from continuous emissions of pollutants into air, water and soil under normal operating conditions. Volume II deals with the assessment of consequences of accidental releases, helping to answer such questions as: What can go wrong? What are the effects and consequences? How often will it happen? £/LIST£ The main procedural steps are supported by relevant, internationally recognised methods of risk assessment. The book also reviews criteria and guidelines for the implementation of risk assessment and management at different stages. Audience: Students, engineers, and scientists in charge of developing new methodologies for hazard analysis and risk assessment; practitioners of environmental protection; local and governmental authorities charged with implementing environmental risk impact procedures and guidelines.