Roughness and ViscoBoundFactor

eduardoRD · August 2017

Hi everyone,

Am working on a simple free surface channel model using differents values of Froude. My idea is determinate the normal height of water with the manning equation and compare the theorical results with the results of the model, but I don't know what roughness to use in the manning equation, because I have no information how the ViscoBoundFactor represent (in terms of the value) different roughness (channels of concrete, steel, natural channels, etc.)

There's a way to know this information? because to validate the model, i have to make the comparisson with the theorical results

Thanks

Alex · August 2017

We have introduce the term ViscoBoundFactor to define a different ALPHA value (artificial viscosity) to be used in the momentum equation solved between fluid and boundary particles. In this way you can use a different viscosity than for interactions between fluid particles. So that, you can just play with the values.
Usually ViscoBoundFactor=0 means alpha for fluid-boundary=alpha*0=0 that can represent glass...
But you have to play with the values.... as we did in FIGURE 6 of:
Barreiro A, Domínguez JM, Crespo AJC, González-Jorge H, Roca D, Gómez-Gesteira M. 2014. Integration of UAV photogrammetry and SPH modelling of fluids to study runoff on real terrains. PLoS ONE, 9(11): e111031. doi:10.1371/journal.pone.0111031.

NWRichmond · August 2017

Thanks, Alex! I've been looking for that.

Here's a link to that figure for anyone who is interested (do read the whole paper, though!): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4220980/figure/pone-0111031-g006/

C_Kesanapalli · March 2019

Urgent!!

But in Barreiro (2014) paper says that the fluid-boundary viscosity = fluid-fluid viscosity for the Plexiglas.

Does that mean ViscoBoundFactor = 1 but not zero for glass (Plexiglas). Can you clarify this.

Roughness and ViscoBoundFactor

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