*2.4. Numerical Setup*

Following Lee et al. (2016) [12], the configuration of Mao (1986) [2] was used as a benchmark to study the time evolution of the bed morphology. A pipeline having a diameter *D* = 5 cm was placed just above a sediment bed made of medium sand (median diameter *d*50 = 360 μm and density *ρs* = 2600 kg·m<sup>−</sup>3). The incoming current had a mean velocity *U* = 0.87 <sup>m</sup>·s<sup>−</sup><sup>1</sup> corresponding to a Shields number *θ*∞ = 0.33. Initially, the pipeline was just laid on the sediment bed with no embedment. Mao (1986) [2] measured the sediment bed profile at different times until scour equilibrium was reached. For the simulations, the dynamics was resolved up to 30 s to ensure that the small perturbations of the sediment bed coming from the inlet did not reach the scour hole.
