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21
Conclusion
The CFD analysis using SolidWorks Flow Simulation, combined with particle tracking studies, provides
clear evidence that strategically designed porous wind fences (50% porosity) can significantly mitigate
fugitive dust emissions from the coal piles at the Newport News terminal. Key findings include:
No-fence baseline results in extremely high escape rates (87–99% for particles), confirming the
need for intervention in prevailing wind directions (SW, SSE, WNW).
Porous fences at 80 ft height with partial wraps (½-wrap or ¾-wrap) deliver the strongest overall
particles drops dramatically (e.g., to as low as 10% in the ½-wrap configuration). This aligns with
established literature on porous windbreaks, where 30–50% porosity optimizes velocity reduction
while minimizing turbulent recirculation and over-the-fence lofting.
Velocity field visualizations confirm that the 80 ft fence creates a broad, low-velocity sheltered
zone (<2 mph) across the piles (60–80 ft tall), effectively suppressing shear stress and initial
particle entrainment without excessive upward deflection.
Taller (100 ft) fences and full-wrap configurations often underperform due to altered flow regimes:
increased recirculation, pressure buildup (especially in full enclosures), and greater particle lofting
over the top—common sensitivities in stockpile-fence interactions.
partial-wrap cases) is attributable to inertial effects and particle-wall interactions (bounce/roll) at
near-fence release heights. Regulatory focus remains on fine
results are robust and directionally consistent.
These simulations demonstrate that fence design must be geometry- and direction-specific rather than
one-size-fits-all: partial wraps provide intentional venting to relieve internal turbulence, while height
–1.3× pile height) yields optimal shelter without regime shifts.
Recommendations for implementation:
Prioritize 80 ft height with 50% porosity in ½-wrap or ¾-wrap configurations, tailored to
dominant winds (e.g., ½-wrap excels for SW exposure based on pile/rail layout).
Avoid full-wrap or 100 ft heights unless site-specific re-runs confirm benefits in other directions.
Supplement with field validation (e.g., TSP monitoring, anemometry) post-installation to confirm
modeled reductions (literature reports 50–80% dust/TSP reductions with similar porous setups).
In summary, the study conclusively supports installation of optimized 80 ft, 50% porous partial-wrap
wind fences as an effective, site-appropriate engineering control for reducing coal dust emissions at the
Newport News terminal. This approach balances aerodynamic efficiency, and regulatory compliance,
offering substantial improvements over the unprotected baseline while highlighting the value of CFD in
avoiding suboptimal designs.
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