A Baroclinic Model of turbulent dusty flows
The problem considered here is the numerical simulation of the turbulent dusty flow induced by explosions over soil surfaces. Some of the unresolved issues are: (1) how much dust is scoured from such surfaces; (2) where does the dust go in the boundary layer; (3) what is the dusty boundary layer height versus time; (4) what are the dusty boundary layer profiles; (5) how much of the dust mass becomes entrained into the dust stem; and (6) where does the dust go in the buoyant cloud? The author proposes a Baroclinic Model for flows with large density variations that actually calculates the turbulent mixing and transport of dust on an adaptive grid. The model is based on the following idealizations: (1) a loose dust bed; (2) an instantaneous shock fluidization of the dust layer; (3) the dust and air are in local equilibrium (so air viscosity enforces the no-slip condition); (4) the dust-air mixture is treated as a continuum dense fluid with zero viscosity; and (5) the turbulent mixing is dominated by baroclinically-generated vorticity. These assumptions lead to an inviscid set of conservation laws for the mixture, which are solved by means of a high-order Godunov algorithm for gasdynamics. Adaptive Mesh Refinement (AMR) is used to capture the turbulent mixing processes on the grid. One of the unique characteristics of these flows is that mixing occurs because vorticity is produced by an inviscid, baroclinic mechanism. A number of examples are presented to illustrate these baroclinic effects including shock interactions with dense-gas layers and dust beds, and dusty wall jets of airblast precursors. The conclusion of these studies is that dusty boundary layers grow because of mass entrainment from the fluidized bed (and not because of viscous wall drag) as proven by the Mass Integral Equation.
- Research Organization:
- Lawrence Livermore National Lab., El Segundo, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10168920
- Report Number(s):
- UCRL-JC-111404; CONF-9204142-2; ON: DE93017122; CNN: Contract DNA IACRO-92-824; TRN: 93:001984
- Resource Relation:
- Conference: DNA numerical methods symposium,Menlo Park, CA (United States),28 Apr 1992; Other Information: PBD: Apr 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
EXPLOSIONS
MATHEMATICAL MODELS
DUSTS
FLUIDIZATION
FLUID MECHANICS
COMPUTERIZED SIMULATION
CONSERVATION LAWS
PRESSURE GRADIENTS
BOUNDARY LAYERS
FLUID FLOW
SOILS
ALGORITHMS
420400
990200
HEAT TRANSFER AND FLUID FLOW
MATHEMATICS AND COMPUTERS