Experimental and numerical studies for flow over a sierpinski tetrahedron for potential windbreak application

Y. S. Lim, P. C. Wang, J. J. Yeo, S. C.M. Yu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)


Investigations have been conducted to study the flow characteristics behind the Sierpinsksi Tetrahedron to assess its potential as windbreaks. Sierpinski Tetrahedrons are fractal sets with an equilateral triangle as its based shape. The upper levels consist of subdivided small equilateral triangles until the apex is reached. Flow over the Sierpinski Tetrahedron at Re = 39,400 and 65,700 were analyzed in an open circuit wind tunnel and the measured velocities were used to validate the numerical simulation results. The validated numerical simulation results showed good agreement in general with the experimental data. 5 models are subsequently chosen to be investigated further numerically, at different orders of fractal sets, from order 0 to order 4. RANS numerical model was used with wind speeds ranging from Reynolds number 2.79 × 105 to 4.48 × 106. The results reveals that higher orders are more effective in reducing wind speed. The percentage in wind speed reduction measured at a distance of 12H (H being the height of the Sierpinski Tetrahedron) away from the Sierpinski Tetrahedron is 32% for orders 2, 3 and 4. Order 4 which has highest porosity has the lowest peak turbulence intensity and highest speed reduction. The present study also shows that staggered formation of laying the Sierpinski Tetrahedrons as windbreaks could help in providing a greater coverage area.

Original languageEnglish
Article number104712
JournalJournal of Wind Engineering and Industrial Aerodynamics
Publication statusPublished - Sept 2021


  • Computational fluid dynamics
  • Laser Doppler velocimetry
  • Sierpinski tetrahedron
  • Wind speed reduction
  • Wind Tunnel
  • Windbreak

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Renewable Energy, Sustainability and the Environment
  • Mechanical Engineering


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