Regularized smoothed particle hydrodynamics with improved multi-resolution handling

Regularized Smoothed Particle Hydrodynamics (RSPH) has been proposed as an extension to Smoothed Particle Hydrodynamics (SPH). Its development has been motivated by the desire to improve the accuracy of the latter method by allowing the resolution to vary in time and space by orders of magnitude and by providing the means to avoid particle penetration. In the current work, an alternative technique for handling stepwise, spatially varying resolution, is proposed. A comparison is made between the original and new RSPH techniques. This includes test results from 2D simulations of linear sound waves as well as weak shocks. In addition, simulation results of two interacting, cylindrical blast waves are presented that provide a comparison between standard SPH with variable smoothing length and RSPH. The test results show that, using the new technique, a more accurate and robust description near steps in the resolution is obtained and that a significant improvement compared to standard SPH is achieved.