PSI - Issue 27

Aldias Bahatmaka et al. / Procedia Structural Integrity 27 (2020) 6–13 Bahatmaka et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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(a)

(b)

Fig. 7. Comparison of (a) means wind vectors (experimental results), and (b) TKE distribution on the vertical (x – z) center plane (CFD k − ε turbulence model) (Cheung et al., 2011).

Fig. 7a shows the mean wind velocity vectors from the k – ε turbulence model. In contrast to the wind tunnel test, the velocity was over-predicted near the roof-level wind-ward edge. One of the most noticeable differences is the inability of the k – ε turbulence model to resolve the ground-level standing vortex at x = −0.5 H . Instead, the CFD calculated only a tiny recirculation immediately ahead of the windward wall near x = − 0.25 H . The downward tendency of the inflow through the windward opening was shown to be partly attributed to this standing vortex in the wind tunnel experiment. Therefore, the CFD underestimated this downward air movement. Hence, the airflow inside the building was a little different from that of the wind tunnel measurement. Above the roof and immediately downwind of the building, the calculated airflow patterns were comparable to those of the wind tunnel data. The upward accelerating flow directly behind the leeward opening was successfully predicted by the k − ε turbulence model. As the turbulent kinetic energy distribution is largely related to the velocity fluctuation and wind shear, following the pattern of the CFD-calculated velocity deviations, the turbulent kinetic energy was under-predicted upwind of the building near the ground level and over-estimated around the roof (Fig. 7b). This discrepancy was also reported earlier in other k – ε CFD simulations on similar cubic structures. Additional CFD simulations were then performed on buildings in configurations with good agreements and close to the experimental. 4. Fluid-structure analysis and occurred damage The fluid-structure analysis is one thing that should be considered for engineering design. The assessment of structural effects is related to the pressure fields. Linear dynamic structure analyses are performed for each considered angle attack to investigate internal forces on structural elements. According to the literature, the sample of the building structure is reported in Fig. 8, and it is 24 m long and 16 m wide, while the height of the columns is 8 m. The roof is composed of six trussed beams positioned every 4.8 m and purling with spacing 2.0 m in plan view. The structural properties of the adopted elements are reported in Table 2, where E is the elastic modulus, A is the cross-section area, and I 11 and I 22 are the principal moments of inertia. The columns are clamped at their base sections. The building is considered to be completely closed on the sides by elements.