Surface Elevation Rise when using DDT

Hi forum,

I've recently been looking at large scale 3D wave simulations at low resolution (dp = 1.0 metre). I am using the Relaxation Zone method and have used the RZ examples as a base to build on, which includes the Density Diffusion Term. I have noticed that although the drift correction maintains an approximately constant number of particles in the domain, the water level continues to rise (figure attached). I noted that without the DDT, this rise essentially disappears however surface elevation measurements become less accurate. I have tried 2D simulations with increased resolutions however the magnitude of the water level rise just reduces with more particles. This appears to be a problem only near the surface. Is there any way to prevent this phenomenon while still using the DDT? My starting water level is 16 metres, I am limited to 1 metre dp due to the size of my domain.


  • Yes, you are right

    This sea level rise appears using DensityDT=1 (Molteni and Colagrossi, 2009, formulation) for long simulations

    This is solved using DensityDT=2 (&=3) based on Fourtakas et al 2019 that will be included in the new version 5 that will be available in the following weeks


  • Thanks for the response @Alex

    I look forward to the new version of DSPH

    Best regards

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