Computational Fluid Dynamics Analysis and Modeling

Science Center Objects

USGS scientists can perform numerical simulations with the FLOW-3D application. FLOW-3D is a computational fluid dynamics (CFD) software package with multi-physics modules. It solves the three-dimensional Navier-Stokes and continuity equations in a structured, rectangular grid. USGS scientists use CFD models to design equipment (such as the USGS DH-84 sediment sampler), assess hydraulic conditions in the field (such as erosion (scour) at bridges), and provide technical assistance to local entities for various local projects.

FLOW-3D is a CFD software package with multi-physics modules. It solves the three-dimensional Navier-Stokes and continuity equations in a structured, rectangular grid.

We recently used FLOW-3D to recreate an experiment done in 1941 on suspended-sediment sampler efficiency.

To recreate the experiment using numerical modeling, we

  • created a 3-D rendering of the sampler nozzle
  • Set boundary conditions: Upstream (specified velocity (V) and particles), Sides (stagnation pressure (P) with tangential velocity), Downstream (static pressure (P))
  • Used the RNG turbulence model
  • Had a constant water temperature of 20º
  • Set a 30 second finish time

Results

Results from sediment sampler test with FLOW-3D
Sampling results from original study compared with numerical model.

Next Steps

3-D rendering of nozzles to be tested with FLOW-3D
  • Testing new variables with previous model setup: Minor improvements to the previous model setup will be made. We will be investigating the effect of different nozzle design and mixed sediment sizes. D-77 nozzle was selected.
  • New model configuration: Model boundary conditions will be modified to represent natural fill conditions and macro-turbulence effects. Several simulations will be completed with variation in mesh configuration and boundary conditions to provide a sensitivity analysis for the model. The objective is to ensure the results are independent of the mesh size and location of boundaries. 
  • Data analysis: As simulations are completed, graphical and numerical analysis of individual simulations and groups of simulations will be completed. These analyses will include but are not limited to: visualization and animations of the flow in and around the nozzle, comparison of model results to other flume and field results, and addition or modification of future simulations to resolve any identified questions or issues.