Investigation of electrohydrodynamic calculations

A perfect dielectric model was incorporated into the OpenFOAM?? software and used for investigation and, possibly, improvements of electrohydrodynamic calculations. Two different sets of numerical simulations were analyzed, in which two different fluids were present. The first set was one-dimensional, while in the second, a drop of one fluid was surrounded by the other fluid. It is shown that oscillations and possible artificial generation of a curl of the electric field strength can be observed at applying certain expressions or calculation strategies, which can be thus abandoned. Usage of dynamic meshes, at least those present in the used software, and of limiters for the gradient of the electric field strength can lead to large numerical errors. It is also shown that usage of certain cell face values could improve the results. An electric Courant number was derived by dimensional analysis, and it could be suggested for future calculations. Conclusions made in this paper are expected to be transferable to other more complicated models.

Automated summary

A perfect dielectric model was introduced into the OpenFOAM software to investigate and potentially improve electrohydrodynamic calculations. Two sets of numerical simulations with different fluids were analyzed. It was found that certain expressions or calculation strategies could cause oscillations and artificial generation of a curl of the electric field strength, thus suggesting that they should be abandoned. The use of dynamic meshes and limiters for the gradient of the electric field strength in the software could lead to significant numerical errors. Additionally, using certain cell face values was shown to improve results. An electric Courant number was derived by dimensional analysis and recommended for future calculations. The conclusions made in this study are expected to be applicable to other more complex models.