Are additional particle stencils implemented with the density diffusion term of Fourtakas et al 2019
This is about the implementation of the density diffusion term in DualSPhysics 5.0. In the XML this is
<parameter key="DensityDT" value="1" comment="Density Diffusion Term 0:None, 1:Molteni, 2:Fourtakas, 3:Fourtakas(full) (default=0)" />
I have read the articles Fourtakas et al 2015 and Fourtakas et al 2019. (In passing, I do invite those tempted to look at them not to resist this temptation: personally I found both really pretty fine research expositions.)
In both articles the kernels of fluid particles approaching the boundary are endowed with extra fictitious particles in the solid domain. In this way there is no loss of information due to an half-full kernel. In both articles, the performance of this auxiliary stencil is improved by the inclusion of hydrostatic pressure/density in the particle properties.
In particular, in the latter article, the treatment is extended to 3D and to a delta-SPH mass conservation equation: there we get basically DensityDT=3, as far as I could understand from another post. So, DensityDT=3 is a density diffusion term extended to include the hydrostatic density. Fourtakas et al. 2019 makes it clear that this formulation does improve the performance of stencils (LUST is the acronym for them) near the solid boundaries.
So, according to the evidence brought forth in the article, it is the pair stencil + extended deltaSPH that does the trick.
I have not found mention of these stencils in the wiki at https://github.com/DualSPHysics/DualSPHysics/wiki/3.-SPH-formulation
- Are the (LUST) stencils of fictitious particles also implemented in DualSPHysics?
- If not, we only have the modified delta-SPH. Are the studies (articles, master theses, etc) on what happens when one implements DensityDT=3 without a special stencil? Would you mind it to share those?
Thanks in advance for considering this.