PSI - Issue 73

Juraj Králik et al. / Procedia Structural Integrity 73 (2025) 73–80 Juraj Králik/ Structural Integrity Procedia 00 (2025) 000–000

76 4

"tetrahedron" elements was transformed into "polyhedral" type of elements, which represent a volume element with 12 nodes. In this way, a reduction in the number of elements to 1 193 211 was achieved, which represents a reduction of the number of elements by 5.3 times.

Fig. 3. The axonometry of the 3D FLUID model with the polyhedral mesh.

Fig. 4. The wind flow around the NPP ventilation chimney at level +15m, flow direction +X and -X.

3.1. Analysis of the wind load on the NPP buildings NPP buildings (EBO V2) are designed for a maximum wind gust at a height of 10 m above the ground with a speed of 53.9 m/s with a return period of 10,000 years in accordance with IAEA (2003) and SHMU (2012). Buildings must withstand a 10-minute duration of wind at a height of 10 m above the ground with a speed of 35.64 m/s with a return period of 10,000 years, SHMU (2012). The basic wind pressure w b is defined in the form:

w b = (1/2) . ρ . v b 2 ,

(2)

where ρ is the air density ( ρ = 1.25 kg/m 3 ) and v b is the basic air velocity. For a wind speed of 53.9 m/s the wind pressure is w max = (1/2) × 1.25 × 53.92 = 1815.76 N/m For a wind speed of 35.64 m/s, the wind pressure is w b = (1/2) × 1.25 × 35.64 = 793.88 N/m

2 = 1.82 kPa. 2 = 0.79 kPa.