"DensityDTvalue"

cadff1

Dear developer,

Good afternoon.

Please, this is not clear for me:

What term of the right side of the Equation below receives the value 0.1 (DensityDTvalue), presented below?

<parameter key="DensityDTvalue" value="0.1" comment="DDT value (default=0.1)" />

The Equation is in the literature:

Domínguez, J.M., Fourtakas, G., Altomare, C. et al. DualSPHysics: from fluid dynamics to multiphysics problems. Comp. Part. Mech. (2021). https://doi.org/10.1007/s40571-021-00404-2

Thanks so much.

Best regards.

Asalih3d

That would be the "delta" in that equation. "h" is the smoothing length, "c" speed of sound of particle a, in DualSPHysics basically a constant. The rest are the terms.

Kind regards

cadff1

Dear colleague,

Thanks for your response.

I also had this suspicion.

It is a dimensionless constant.

Regards.

Alex

Page 136 of XML_GUIDE_v5.0.pd in DualSPHysics_v5.0\doc\guides

cadff1

Thanks, Alex.

Lucy

hi you all,

I note that the defult value of DensityDTvalue is 0.1. Can i change it to another value, such as 0.01? Does it affect the simulation result stongly?

Kind regards,

Lucy

Alex

The value is based on details studies conducted by the developers of the so-called delta-SPH formulation.

You can find more information here:

Antuono M, Colagrossi A, Marrone S, Molteni D. 2010. Free-surface flows solved by means of sph schemes with numerical diffusive terms. Computer Physics Communications, 181 (3), 532-549.

Antuono M, Colagrossi A, Marrone S. 2012. Numerical diffusive terms in weakly-compressible SPH schemes. Computer Physics Communications, 183 (12), 2570-2580.

cadff1

Thanks, Alex.