Hydrodynamic drag on non-spherical floc and free-settling test
Water Research
|August 7, 2001
Summary
This study numerically investigates hydrodynamic drag on porous spheroids. A universal correlation for drag force was developed, applicable across Reynolds numbers and accounting for shape and permeability.
Area of Science:
- Fluid Dynamics
- Particle Science
- Rheology
Background:
- Understanding hydrodynamic drag on porous particles is crucial in various fields.
- Previous correlations often limited to low Reynolds numbers or specific shapes.
Purpose of the Study:
- To numerically investigate hydrodynamic drag on porous spheroids.
- To develop a universal correlation for drag force, aspect ratio, and permeability.
- To assess the impact of non-spherical shape on settling sludge.
Main Methods:
- Numerical simulations of fluid flow around porous spheroids.
- Analysis of flow patterns across a wide Reynolds number range.
- Free-settling experiments with sludge samples.
Main Results:
- Flow patterns remain similar across Reynolds numbers, extending correlation applicability.
- Shape effects on drag become more pronounced with increased porosity.
- A universal correlation using equivalent diameter was established.
- Free-settling tests indicated 16-34% error due to shape and permeability.
Conclusions:
- The developed correlation offers a broader applicability for predicting drag on porous spheroids.
- Non-spherical shape and internal permeability significantly influence settling behavior and introduce errors.
- Further research can refine drag predictions for complex particle shapes.
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