RESEARCH ON NON-GAUSSIAN WIND PRESSURE OF FOUR SUPER-LARGE COOLING TOWERS UNDER DIFFERENT LAYOUTS

Non-Gaussian wind pressure is one of the important factors which cause excessive local wind pressure of cooling tower, and the interference effect of tower group will significantly change the non-Gaussian distribution of wind pressure. Four-tower arrangements are the most common patterns for super-large cooling towers. With the highest cooling tower (220 m) in the world under construction, wind tunnel tests for rigid body were performed under five typical four-tower arrangements in engineering practice, i.e., single row, rectangular, rhombic, L-shaped, and oblique L-shaped. On this basis, statistical analyses were performed on the wind pressure signals in the amplitude and time domains under different four-tower combination. Contrastive study on the two-dimensional (2-D) and 3-D peak factor of cooling tower considering the four-tower disturbance effect were analyzed. The influence of different four-tower combination on the non-Gaussian characteristics of wind pressure was discussed. The results show that the magnitude of non-Gaussian wind pressure signals under the single-row, rectangular, rhombic, L-shaped and oblique L-shape arrangements increases by 11%, 63%, 56%, 89% and 30%,respectively, as compared with the single tower. The peak factor method based on the Gaussian distribution assumption will cause greater errors than the Sadek-Simiu method. The peak factors of the single-row and oblique L-shaped arrangements are less affected by the interference effect, while the peak factors of rectangular, rhombic and L-shaped arrangements increase dramatically; the peak factors in some positions of the cooling tower are above 6.5 for the rectangular, rhombic and L-shaped arrangements. In this paper, the causes of excessive local wind pressure of cooling tower under the four-tower combination were analyzed from the perspective of formation mechanism, which could be used to calculate the extreme wind pressure of cooling tower under different four-tower combinations.