Why does interfacial anti-diffusion in high viscosity ratio injection simulation show unstable spikes in velocity and pressure field?
For faster convergence in VOF simulation, implicit formulation for volume fraction is used. It allows for larger time steps. Also, this interfacial anti diffusion option is used for increasing interfacial accuracy for sharp interfaces. In this set up, users can see unstable spikes in velocity and pressure fields.
Please refer to the attached document below for more information.