WG1 Draft 2026 (Gomboc) (WIP)

Benchmark Description	Tests the performance of codes doing shape And, our ability to handle complex shapes for industrial problems
Target Result (e.g. How close to an analytical solution?)
Benchmark Geometry and Boundary Conditions Drum diameter: 20 cm Drum thickness: 6 cm File type(s) for geometry -e.g. .stl, etc.:
File name	Description	Location/link

Image(s) (Paste here)
Particle Type	sphere clumps polyhedra level sets Here are a couple of links to gomboc shaped particle GomBSTL GomBOBJ
Mixture Type	Monodisperse
Particle properties
In case of multi-spheres / clumped-spheres
Diameter	M1 (2 mm) and M2 (4 mm) settings from Dosta benchmark paper. Take monodisperse M1 or M2 or polydisperse? Resolution: the lowest that still makes the Gomboc self-correct its orientation. Particle A: 0.020 m Each Gomboc particle has a volume given by 2x Particle A diameter (0.02m) = 0.04m Resulting Gomboc particle is composed of around 2270 elements (STL triangles) For 1000 particles this would give a total of 2270000 elements In case you can’t get a smooth enough surface with clumped spheres then use more particles However, this could affect the computational cost But this is something we will look into when considering clump-sphere vs polyhedra, superquadrics or other elements.
E (GPa)	Particle A (sphere): 0.1 GPa = 1e8 N/m2 or 0.05 GPa = 5e7 N/m2
v	Particle A (sphere): 0.2
density (kg/m³)	Particle A (sphere): 2500 kg/m3 or 2000 kg/m3
Contact model(s) and properties Hertz Mindlin with tangential history
Simulation setup
Time-step	sqrt(10)*0.8e-6
Gravity	9.81 m/s2
Total time	2.25 seconds (1 rev) Dosta: 5 seconds
Rotation speed:	-30 after the first 0.25 seconds Dosta: 2 rad/s
Data output interval	Every 0.25 seconds VTK: Every 0.10 seconds Dosta: Every 0.1 seconds
Additional info	Sanity measures Average velocity Energy dissipation Power
Initial configuration Repository link and file name: Click here for the start file To view in VTK, click here for the OBJ file Additional details and images:
Output data format The Open DEM format must be used. Please specify format for any data not specified. Include an example as a file stored in a repository Repository link and file name: Additional specifications: