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Numerical and Experimental Study on Drag Force of Calcareous Sand

Project Overview​

  • Level: University Level
  • Principal Investigator: Liu Mingjing
  • Advisors: Lai Zhengshou, Huang Linchong
  • Duration: Jan 2023 - Dec 2023

Background and Significance​

Calcareous sand is a widely distributed marine sediment in the South China Sea with unique biogenic structures and mechanical properties. In island reef engineering construction, the movement patterns of calcareous sand under wave and current actions are critical for assessing engineering stability. As the fundamental force in particle-fluid interaction, accurately measuring and predicting the drag force of calcareous sand particles is essential for understanding their hydrodynamic behavior.

This project innovatively couples the open-source CFD software OpenFOAM with the research group's self-developed NetDEM discrete element program to establish a CFD-DEM numerical simulation platform, combined with laboratory physical experiments to systematically study the drag force characteristics of calcareous sand particles in flow fields.

CFD-DEM coupled simulation of calcareous sand particle settling
CFD-DEM coupled simulation of calcareous sand particle settling

Conceptual schematic of CFD-DEM coupled settling simulation of calcareous sand particles (ClaudeBot generated)

Research Content​

CFD-DEM Coupling Platform Development

  • Implementing bidirectional data exchange between OpenFOAM and NetDEM
  • Developing particle-fluid force calculation interfaces
  • Validating coupling program accuracy on standard benchmarks

Regular Particle Numerical Simulation

  • Establishing settling models for ellipsoidal and polyhedral particles
  • Systematically studying the influence of aspect ratio (EI) and flatness (FI) on terminal velocity
  • Comparison with existing laboratory experimental results

Calcareous Sand Laboratory Experiments

  • Building transparent settling apparatus for single-particle settling experiments
  • Using high-speed cameras to record particle motion trajectories
  • Analyzing settling velocity data through Tracker software

Real Particle Numerical Simulation

  • Obtaining real calcareous sand particle shapes based on CT scanning
  • CFD-DEM simulation of simplified particle models
  • Comparing numerical results with experimental data

Technical Approach​

  • CFD Software: OpenFOAM
  • DEM Software: NetDEM (in-house)
  • Coupling: Bidirectional fluid-structure coupling
  • Equipment: Transparent settling tower, high-speed camera
  • Analysis: MATLAB/Python

Project Outcomes​

Software Copyrights

  • 2 software copyrights approved based on developed CFD-DEM interface tools

Competition Awards

  • Won award in International Rock Mechanics and Engineering Numerical Simulation Competition using software developed in this project

Experience Accumulation

  • Mastered core technologies of CFD-DEM coupling methods
  • Accumulated experience in particle material fluid-structure coupling research

University Innovation and Entrepreneurship Training Program Project, 2023