A Lagrangian stochastic model for turbulent dispersion

2001 ◽  
Vol 15 (12) ◽  
pp. 1683-1690
Author(s):  
Changhoon Lee ◽  
Byunggu Kim ◽  
Namhyun Kim
Keyword(s):  
Stochastic Model ◽  
Turbulent Dispersion ◽  
Lagrangian Stochastic Model

Turbulent dispersion in a non-homogeneous field

1999 ◽  
Vol 392 ◽  
pp. 45-71 ◽  
Author(s):  
ILIAS ILIOPOULOS ◽  
THOMAS J. HANRATTY
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Stochastic Model ◽  
Point Source ◽  
Time Scales ◽  
Langevin Equation ◽  
Turbulent Dispersion ◽  
Homogeneous Field ◽  
Fully Developed Flow ◽  
Good Agreement

Dispersion of fluid particles in non-homogeneous turbulence was studied for fully developed flow in a channel. A point source at a distance of 40 wall units from the wall is considered. Data obtained by carrying out experiments in a direct numerical simulation (DNS) are used to test a stochastic model which utilized a modified Langevin equation. All of the parameters, with the exception of the time scales, are obtained from Eulerian statistics. Good agreement is obtained by making simple assumptions about the spatial variation of the time scales.

Non-Gaussianity in turbulent relative dispersion

2019 ◽  
Vol 867 ◽  
pp. 877-905
Author(s):  
B. J. Devenish ◽  
D. J. Thomson
Keyword(s):  
Stochastic Model ◽  
Velocity Distribution ◽  
Relative Velocity ◽  
Isotropic Turbulence ◽  
Dispersion Model ◽  
Original Model ◽  
Direct Numerical Simulations ◽  
Relative Dispersion ◽  
Lagrangian Stochastic Model ◽  
Homogeneous Isotropic Turbulence

We present an extension of Thomson’s (J. Fluid Mech., vol. 210, 1990, pp. 113–153) two-particle Lagrangian stochastic model that is constructed to be consistent with the $4/5$ law of turbulence. The rate of separation in the new model is reduced relative to the original model with zero skewness in the Eulerian longitudinal relative velocity distribution and is close to recent measurements from direct numerical simulations of homogeneous isotropic turbulence. The rate of separation in the equivalent backwards dispersion model is approximately a factor of 2.9 larger than the forwards dispersion model, a result that is consistent with previous work.

Lagrangian Stochastic Model for the Dispersion of Solid-State Radionuclides Released from Uranium Mine Ventilation Shafts

2012 ◽  
Vol 573-574 ◽  
pp. 461-465
Author(s):  
Dong Xie ◽  
Ze Hua Liu ◽  
Jun Xiong ◽  
Yong Jun Ye
Keyword(s):  
Surface Roughness ◽  
Solid State ◽  
Stochastic Model ◽  
Atmospheric Dispersion ◽  
Three Dimensional ◽  
Mine Ventilation ◽  
Uranium Mine ◽  
Lagrangian Stochastic Model ◽  
Wind Speeds ◽  
Ventilation Shaft

Radionuclides released from uranium mine ventilation shafts would pose radiation exposure to the public and environment. A three-dimensional lagrangian stochastic model has been presented to study the atmospheric dispersion of solid-state radionuclides released from the uranium-bearing mine ventilation shafts. Meteorological conditions and geographical conditions including four downwind velocities (0.5, 1.0, 2.0, 4.0 m/s) and two underlying surface roughness characteristics (0.1 m, 1.0 m) were chose in the study. The radionuclides concentration distributions at various wind speeds and surface roughness were attained to evaluate the pollution in the vicinity of uranium mine ventilation shaft.

A Lagrangian stochastic model for tetrad dispersion

2013 ◽  
Vol 14 (3) ◽  
pp. 107-120 ◽  
Author(s):  
B. J. Devenish ◽  
D. J. Thomson
Keyword(s):  
Stochastic Model ◽  
Lagrangian Stochastic Model
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