  A major issue in Smoothed Particle Hydrodynamics (SPH) approaches is the
numerical dissipation during the projection process, especially under coarse
discretizations. High-frequency details, such as turbulence and vortices, are
smoothed out, leading to unrealistic results. To address this issue, we
introduce a Vorticity Refinement (VR) solver for SPH fluids with negligible
computational overhead. In this method, the numerical dissipation of the
vorticity field is recovered by the difference between the theoretical and the
actual vorticity, so as to enhance turbulence details. Instead of solving the
Biot-Savart integrals, a stream function, which is easier and more efficient to
solve, is used to relate the vorticity field to the velocity field. We obtain
turbulence effects of different intensity levels by changing an adjustable
parameter. Since the vorticity field is enhanced according to the curl field,
our method can not only amplify existing vortices, but also capture additional
turbulence. Our VR solver is straightforward to implement and can be easily
integrated into existing SPH methods.
