Numerical data for "Barchan dune responses to a pair of obstacles"

Description

This simulation models the formation and evolution of a barchan dune under turbulent flow conditions, as it interacts with obstacles placed within the domain. It captures the coupled dynamics between the fluid phase and the granular bed, allowing for the analysis of sediment transport, dune migration, and morphological changes. In particular, the presence of obstacles modifies the local flow field and sediment flux, influencing dune shape, displacement, and stability over time.

Steps to reproduce

The complete setup of the case is available in the BC folder. The simulation is carried out in sequential stages. First, turbulence is developed through a fluid-only simulation using OpenFOAM. Then, an initial granular pile is introduced into a stationary fluid domain. Finally, both configurations are combined to simulate the formation of a barchan dune and its interaction with obstacles. 1) Mesh Generation and Case Initialization The computational mesh is generated by modifying the file InputData.m located in the Octave_blockMesh folder, which defines the domain geometry and obstacle arrangement. The user must specify: The spacing between objects in the streamwise (x) and spanwise (z) directions: Space_c_obj and Space_l_obj; The obstacle dimensions: (l_obj, h_obj, c_obj); The mesh resolution parameters: (min_dx, min_dz, etc.); The object distribution via POS_MATRIX. In the present base case, the blocks are separated by a distance D_o = 0.5W_o, consistent with the main manuscript. Octave workflow: Adjust parameters in InputData.m; Run mainCode.m to generate the mesh; Execute ALLRUN in the main folder; Proceed with the simulation cases. 2) Turbulence Initialization (Fluid Phase Only) A Large Eddy Simulation (LES) is performed in OpenFOAM using the generated mesh and provided turbulence model. This step considers only the fluid phase and generates the initial turbulent flow field. Run the allrun executable in the Fluid_Initialization folder. 3) Particle Initialization The granular bed is initialized by running allrun in: BC/particleInitialization This step inserts and settles the particles within the domain. 4) Coupling Fluid and Particle Initial Conditions After particle settling: Copy the latest OpenFOAM results to BC/run/CFD/0; Copy the restart file to BC/run/DEM/post/restart. This ensures consistent initial conditions for the coupled simulation. 5) Final Coupled Simulation Run Allrun_CFDEM in: BC/run This executes the fully coupled CFD–DEM simulation of dune evolution and interaction with obstacles. 6) Post-Processing and Analysis Post-processing tools are available in: BC/run/Octave_Traj These scripts allow extraction of: Particle trajectories; Forces on grains; Velocity fields; Other relevant quantities from LIGGGHTS outputs. To use them: Modify inputData.m with case parameters; Run mainCode.m; Optionally adjust plotData.m for visualization.

Institutions

• Universidade Estadual de Campinas (UNICAMP)

  São Paulo, Campinas
• University of Minnesota

  Minnesota, Minneapolis
• University of Duisburg-Essen

  North Rhine-Westphalia, Essen

Categories

Funders

• Conselho Nacional de Desenvolvimento Científico e Tecnológico

  Ministry of Science, Technology and Innovation

  Brasília

  Grant ID: 405512/2022-8
• Fundação de Amparo à Pesquisa do Estado de São Paulo

  São Paulo

  Grant ID: Grants ID: 2018/14981-7, 2024/13981-4, and 2025/20488-5

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