The folder example of HydroForceEngine contains three different type of examples: 
- One-way coupling examples, meaning that the fluid is imposed and the HydroForceEngine is used only to apply fluid forces (drag and buoyancy) on the particles from the 1D prescribed fluid profile and the fluid properties. These are: buoyantParticles.py, fluidizedBed.py and sedimentTransportExample.py. In the latter, the HydroForceEngine is also used to evaluate 1D volume-averaged solid depth profiles, which can be plotted with postProcessing_sedim.py
- Two-way coupling examples, which consider the exact same configuration as sedimentTransportExample.py but include a resolution of the volume-averaged 1D fluid momentum balance, i.e. a so-called 1D RANS coupling to the DEM. A precise description of the coupling can be found in Maurin (2015) and Maurin et al (2015). This coupling is used throughout all the examples of the section, in a laminar configuration, studying segregation with bi-disperse script (from Remi Chassagne) and studying the shape effect with script varying the aspect ratio (from Remi Monthiller). This coupling is using the engine HydroForceEngine to apply the fluid forces (drag and buoyancy) on the particles from a given 1D fluid profile (basic function of HydroForceEngine when activated), evaluate 1D volume-averaged solid depth profiles (velocity, volume fraction, drag force; averageProfile() function of HydroForceEngine), and solve the 1D volume-averaged fluid momentum (fluidModel function of HydroForceEngine) from the averaged solid quantities determined.
- Resolution validation scripts, divided in fluid resolution validation examples, lubrication validations example, and DEM coupling validations. The first considers classical validation for the 1D fluid momentum balance resolution, i.e. poiseuille flow and logarithmic profiles (These scripts use only the fluidModel function of HydroForceEngine). The second considers particles rebound validation script of the lubrication formulation both in HydroForceEngine and in the Law2_ScGeom_ViscElPhys_Basic. Last, the DEM coupling is validated performing an experimental comparison reproducing Maurin et al (2015), and a numerical validation reproducing the simulation r2d6s2 of Maurin et al 2016. An additional quickvalidations script allows one to compare the effect of modifications in the source code on the DEM coupling. 
