Pair and multi-particle dispersion in numerical simulations of convective boundary layer turbulence

2014 ◽  
Vol 26 (5) ◽  
pp. 055110 ◽  
Author(s):  
I. M. Mazzitelli ◽  
F. Fornarelli ◽  
A. S. Lanotte ◽  
P. Oresta
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Convective Boundary Layer ◽  
Particle Dispersion ◽  
Convective Boundary ◽  
Boundary Layer Turbulence

scholarly journals Conceptual study on nucleation burst evolution in the convective boundary layer – Part I: Modelling approach

2005 ◽  
Vol 5 (6) ◽  
pp. 11413-11487 ◽  
Author(s):  
O. Hellmuth
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Ultrafine Particle ◽  
Particle Formation ◽  
Convective Boundary ◽  
Aerosol Dynamics ◽  
Boundary Layer Turbulence ◽  
Model Setup ◽  
Conceptual Study ◽  
Modelling Approach

Abstract. A high-order modelling approach to interprete 'continental-type' particle formation bursts in the anthropogenically influenced convective boundary layer (CBL) is proposed. The model considers third-order closure for planetary boundary layer turbulence, sulfur and ammonia chemistry and aerosol dynamics. In part I of the present paper, previous observations of ultrafine particle evolution are reviewed, model equations are derived, the model setup for a conceptual study on binary and ternary homogeneous nucleation is defined, and shortcomings of process parameterization are discussed. In subsequent parts of the paper simulation results obtained within the framework of a conceptual study on the CBL evolution and new particle formation (NPF) will be presented and compared with observational findings.

scholarly journals Lagrangian Particle Dispersion Modeling of the Fumigation Process Using Large-Eddy Simulation

2005 ◽  
Vol 62 (6) ◽  
pp. 1932-1946 ◽  
Author(s):  
Si-Wan Kim ◽  
Chin-Hoh Moeng ◽  
Jeffrey C. Weil ◽  
Mary C. Barth
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Convective Boundary Layer ◽  
Particle Dispersion ◽  
Lagrangian Particle ◽  
Convective Boundary ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Entrainment Zone ◽  
The Mean

Abstract A Lagrangian particle dispersion model (LPDM) is used to study fumigation of pollutants in and above the entrainment zone into a growing convective boundary layer. Probability density functions of particle location with height and time are calculated from particle trajectories driven by the sum of the resolved-scale velocity from a large-eddy simulation (LES) model and the stochastic subgrid-scale (SGS) velocity. The crosswind-integrated concentration (CWIC) fields show good agreement with water tank experimental data. A comparison of the LPDM output with an Eulerian diffusion model output based on the same LES flow shows qualitative agreement with each other except that a greater overshoot maximum of the ground-level concentration occurs in the Eulerian model. The dimensionless CWICs near the surface for sources located above the entrainment zone collapse to a nearly universal curve provided that the profiles are time shifted, where the shift depends on the source heights. The dimensionless CWICs for sources located within the entrainment zone show a different behavior. Thus, fumigation from sources above the entrainment zone and within the entrainment zone should be treated separately. An examination of the application of Taylor’s translation hypothesis to the fumigation process showed the importance of using the mean boundary layer wind speed as a function of time rather than the initial mean boundary layer wind speed, because the mean boundary layer wind speed decreases as the simulation proceeds. The LPDM using LES is capable of accurately simulating fumigation of particles into the convective boundary layer. This technique provides more computationally efficient simulations than Eulerian models.

scholarly journals Structures of Bragg Scatter Observed with the Polarimetric WSR-88D

2013 ◽  
Vol 30 (7) ◽  
pp. 1253-1258 ◽  
Author(s):  
Valery M. Melnikov ◽  
Richard J. Doviak ◽  
Dusan S. Zrnić ◽  
David J. Stensrud
Keyword(s):  
Boundary Layer ◽  
Signal Processing ◽  
Data Collection ◽  
Convective Boundary Layer ◽  
Dual Polarization ◽  
Detection Capability ◽  
Convective Boundary ◽  
Boundary Layer Turbulence ◽  
Fine Structures

Abstract Enhancements to signal processing and data collection in the dual-polarization Weather Surveillance Radar-1988 Doppler (WSR-88D) to increase its detection capability yield observations of “fine” structures from Bragg scatterers. Several types of the fine structures observed in and above the boundary layer are discussed. These Bragg scatter structures include the top of the convective boundary layer, nonprecipitating clouds, strong convective plumes above the boundary layer, and a layer of weak reflections associated with decaying boundary layer turbulence. A conclusion that data from polarimetric WSR-88Ds can be used to obtain the depth of the convective boundary layer is made.

scholarly journals Columnar modelling of nucleation burst evolution in the convective boundary layer – first results from a feasibility study Part I: Modelling approach

2006 ◽  
Vol 6 (12) ◽  
pp. 4175-4214 ◽  
Author(s):  
O. Hellmuth
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Ultrafine Particle ◽  
Particle Formation ◽  
Convective Boundary ◽  
Aerosol Dynamics ◽  
Boundary Layer Turbulence ◽  
First Results ◽  
Conceptual Study ◽  
Modelling Approach

Abstract. A high-order modelling approach to interpret "continental-type" particle formation bursts in the anthropogenically influenced convective boundary layer (CBL) is proposed. The model considers third-order closure for planetary boundary layer turbulence, sulphur and ammonia chemistry as well as aerosol dynamics. In Paper I of four papers, previous observations of ultrafine particle evolution are reviewed, model equations are derived, the model setup for a conceptual study on binary and ternary homogeneous nucleation is defined and shortcomings of process parameterisation are discussed. In the subsequent Papers II, III and IV simulation results, obtained within the framework of a conceptual study on the CBL evolution and new particle formation (NPF), will be presented and compared with observational findings.

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