# NUMERICAL SIMULATIONS OF KELVIN–HELMHOLTZ INSTABILITY: A TWO-DIMENSIONAL PARAMETRIC STUDY

## Abstract

Using two-dimensional simulations, we numerically explore the dependences of Kelvin–Helmholtz (KH) instability upon various physical parameters, including viscosity, the width of the sheared layer, flow speed, and magnetic field strength. In most cases, a multi-vortex phase exists between the initial growth phase and the final single-vortex phase. The parametric study shows that the evolutionary properties, such as phase duration and vortex dynamics, are generally sensitive to these parameters, except in certain regimes. An interesting result is that for supersonic flows, the phase durations and saturation of velocity growth approach constant values asymptotically as the sonic Mach number increases. We confirm that the linear coupling between magnetic field and KH modes is negligible if the magnetic field is weak enough. The morphological behavior suggests that the multi-vortex coalescence might be driven by the underlying wave–wave interaction. Based on these results, we present a preliminary discussion of several events observed in the solar corona. The numerical models need to be further improved to perform a practical diagnostic of the coronal plasma properties.

- Authors:

- Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 (China)

- Publication Date:

- OSTI Identifier:
- 22667541

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Astrophysical Journal; Journal Volume: 824; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COALESCENCE; COMPUTERIZED SIMULATION; COUPLING; HELMHOLTZ INSTABILITY; INTERACTIONS; LAYERS; MACH NUMBER; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PARAMETRIC ANALYSIS; PLASMA; SATURATION; SOLAR CORONA; SUN; SUPERSONIC FLOW; TWO-DIMENSIONAL CALCULATIONS; VISCOSITY; VORTICES

### Citation Formats

```
Tian, Chunlin, and Chen, Yao, E-mail: chunlin.tian@sdu.edu.cn.
```*NUMERICAL SIMULATIONS OF KELVIN–HELMHOLTZ INSTABILITY: A TWO-DIMENSIONAL PARAMETRIC STUDY*. United States: N. p., 2016.
Web. doi:10.3847/0004-637X/824/1/60.

```
Tian, Chunlin, & Chen, Yao, E-mail: chunlin.tian@sdu.edu.cn.
```*NUMERICAL SIMULATIONS OF KELVIN–HELMHOLTZ INSTABILITY: A TWO-DIMENSIONAL PARAMETRIC STUDY*. United States. doi:10.3847/0004-637X/824/1/60.

```
Tian, Chunlin, and Chen, Yao, E-mail: chunlin.tian@sdu.edu.cn. Fri .
"NUMERICAL SIMULATIONS OF KELVIN–HELMHOLTZ INSTABILITY: A TWO-DIMENSIONAL PARAMETRIC STUDY". United States. doi:10.3847/0004-637X/824/1/60.
```

```
@article{osti_22667541,
```

title = {NUMERICAL SIMULATIONS OF KELVIN–HELMHOLTZ INSTABILITY: A TWO-DIMENSIONAL PARAMETRIC STUDY},

author = {Tian, Chunlin and Chen, Yao, E-mail: chunlin.tian@sdu.edu.cn},

abstractNote = {Using two-dimensional simulations, we numerically explore the dependences of Kelvin–Helmholtz (KH) instability upon various physical parameters, including viscosity, the width of the sheared layer, flow speed, and magnetic field strength. In most cases, a multi-vortex phase exists between the initial growth phase and the final single-vortex phase. The parametric study shows that the evolutionary properties, such as phase duration and vortex dynamics, are generally sensitive to these parameters, except in certain regimes. An interesting result is that for supersonic flows, the phase durations and saturation of velocity growth approach constant values asymptotically as the sonic Mach number increases. We confirm that the linear coupling between magnetic field and KH modes is negligible if the magnetic field is weak enough. The morphological behavior suggests that the multi-vortex coalescence might be driven by the underlying wave–wave interaction. Based on these results, we present a preliminary discussion of several events observed in the solar corona. The numerical models need to be further improved to perform a practical diagnostic of the coronal plasma properties.},

doi = {10.3847/0004-637X/824/1/60},

journal = {Astrophysical Journal},

number = 1,

volume = 824,

place = {United States},

year = {Fri Jun 10 00:00:00 EDT 2016},

month = {Fri Jun 10 00:00:00 EDT 2016}

}