[Kaushik15]

Hello professors,
In the paper Ahmad et al. (2019) "Numerical Modelling of Pipeline Scour under the Combined Action of Waves and Current with Free-Surface Capturing", it is clearly mentioned in page 17 that "a negligible gap between the sediment bed and the pipeline, i.e. e=dx/2 is introduced for all calculations". The way I understood this was that there is a gap of half the grid size, (which for a 0.01m grid is 0.005m) between the pipeline and the bed.

However, I am unable to obtain any pipeline scouring by employing this small of a gap. Upon further inspection, I saw that there was no flow happening in that gap (velocity is almost zero). It was only when I increased the gap to 1.5x the grid size (0.015) that I got some flow velocity in the gap.

Please provide further clarification on what is the minimum gap that should be employed for pipeline scouring. I have attached the ctrl.txt, control.txt and the scouring vs. time plot for your reference.

control.txt

ctrl.txt

SedimentMax Plot.png