NF85: A three-dimensional, air-dynamics computer code for analyzing explosions in structures

Technical Report · Tue Dec 01 00:00:00 EST 1987

OSTI ID:5609538

Steinke, R G

The NF85 (Near-Field 85) computer program analyzes the effect of explosions on the dynamic behavior of air in structures. The explosion is modeled as a time- and spallese-dependent source of equivalent air mass and energy. Chemical reactions can be modeled directly with a combustion-model option, and tracer particles may be used to monitor combustion-products convection by the air. The near-field region of the explosion is modeled in three-dimensional cartesian or cylindrical geometry. Internal structures can be defined in the region to reflect shock waves and obstruct airflow. A convenient dump/restart capability allows the movement or removal of internal structures during the transient solution. The effects of the surrounding far-field region are modeled at the three-dimensional region's external boundary by a wall surface, time- and space-dependent pressure or velocity boundary conditions, and/or one-dimensional cartesian-geometry regions attached to openings in the external boundary. Ventilation ducts, passageways, and adjacent rooms can be modeled directly with one-dimensional regions, and the presence of blowers and filters can be modeled as well. One-dimensional regions in NF85 cannot be interconnected, thus requiring the approximation of complex flow-network geometry in the far field. An approximate far-field representation only needs to model its feedback effect on the near-field region accurately to obtain an accurate near-field solution. From it solution, NF85 can optionally edit the time-dependent solution-state condition at any location in its region of solution. This then may be used as an accurate boundary condition for the EVENT84 one-dimensional flow-network computer program to enable it to efficiently evaluate the air-dynamics behavior in a complex flow-network geometry of the far field.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5609538
• Report Number(s): LA-11158-M; ON: DE88005085
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
• Country of Publication: United States
• Language: English

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