# Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

## Abstract

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting a value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES–LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to themore »

- Authors:

- Department of Aerospace Engineering, Nagoya University, Nagoya (Japan)

- Publication Date:

- OSTI Identifier:
- 22598910

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physics of Fluids; Journal Volume: 28; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 42 ENGINEERING; DIFFUSION; FLOW MODELS; FLUIDS; GRIDS; JETS; LAGRANGIAN FUNCTION; LARGE-EDDY SIMULATION; LAYERS; LENGTH; MIXING; NUMERICAL ANALYSIS; PARTICLE INTERACTIONS; PARTICLES; PERFORMANCE; SCALAR FIELDS; SCALARS; STATISTICS; TURBULENCE

### Citation Formats

```
Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp, and Nagata, K.
```*Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing*. United States: N. p., 2016.
Web. doi:10.1063/1.4960770.

```
Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp, & Nagata, K.
```*Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing*. United States. doi:10.1063/1.4960770.

```
Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp, and Nagata, K. Mon .
"Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing". United States.
doi:10.1063/1.4960770.
```

```
@article{osti_22598910,
```

title = {Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing},

author = {Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp and Nagata, K.},

abstractNote = {We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting a value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES–LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.},

doi = {10.1063/1.4960770},

journal = {Physics of Fluids},

number = 8,

volume = 28,

place = {United States},

year = {Mon Aug 15 00:00:00 EDT 2016},

month = {Mon Aug 15 00:00:00 EDT 2016}

}