Copyright (C) 2023 YYGroup [email protected]

The vortex-surface field (VSF) provides a systematic Lagrangian-based framework for the identification, characterization, and modeling of flow structures. As a general flow diagnostic tool, the numerical VSF solution can be constructed in arbitrary flow fields by solving a pseudo-transport equation driven by the frozen, instantaneous vorticity. From post-processing of large-scale database of numerical simulations, the VSF elucidates mechanisms in the flows with essential vortex dynamics, such as turbulence and transition.

vsfFOAM is a free, open-source computational fluid dynamics package released by YYGroup for VSF calculations. It provides a post-processing tool vsfPseudoEvo to obtain the VSF via solving the pseudo-transport equation based on velocity field. Three solvers, vsfIcoFoam, vsfPimpleFoam, and vsfRhoPimpleFoam are included to calculate the VSF evolution with the two-time method for incompressible and compressible flows.

vsfFOAM is built on OpenFOAM. The current version has been validated on OpenFOAM v10.

0. Load the OpenFOAM environment
1. Download the package, put at $FOAM_INST_DIR
2. Execute the script Allwmake to compile the program

To obtain the VSF evolution, simply setup the case as OpenFOAM simulations. Additional files for VSF calculations include the initial field and a dictionary file <system/vsfDict>.

Check out the example in <vsfFOAM/tutorials/>. The script <run.sh> describes how to run the program.

vsfFOAM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. See the file =COPYING= in this directory or [[http://www.gnu.org/licenses/]], for a description of the GNU General Public License terms under which you can copy the files.

[1] Y. Yang, Theory and applications of the vortex-surface field, Chinese Science Bulletin, 65, 483-495, 2020 (In Chinese)

[2] S. Xiong and Y. Yang, Identifying the tangle of vortex tubes in homogeneous isotropic turbulence, Journal of Fluid Mechanics, 874, 952-978, 2019

[3] Y. Zhao, Y. Yang, and S. Chen, Vortex reconnection in the late transition in channel flow, Journal of Fluid Mechanics, 802, R4, 2016

[4] Y. Yang and D. I. Pullin, Evolution of vortex-surface fields in viscous Taylor-Green and Kida-Pelz flows, Journal of Fluid Mechanics, 685, 146-164, 2011

[5] Y. Yang and D. I. Pullin, On Lagrangian and vortex-surface fields in flows with Taylor-Green and Kida-Pelz initial conditions, Journal of Fluid Mechanics, 661, 446-481, 2010