Numerical Simulation Of Wind Induced Mean Interference Between Two Tall Buildings

The assessment of wind loads on structure is generally carried out using existing codes/standards. The specifications of these codes are based on wind tunnel experiment performed on an isolated building. However, the buildings seldom exist in isolated condition. Neighbouring building may either increase or decrease the wind loads on principal building, this effect is known as interference effect. In this paper interference effect between two buildings is studied through numerical simulation using ANSYS CFX. Total drag force and interference factors for the principal building is calculated in the presence of interfering building having height ratio of 0.5, 0.75,1, 1.25, and 1.5. The results show that the upstream interfering buildings cause certain shielding effect by decreasing the mean wind load on the downstream principal building. However an amplification effect is also observed for certain location of the interfering building on upstream side. For buildings of the same cross-section, the interference factor (IF) decreases with the increase of the height of interfering building, indicating increase in the shielding effects. However the shielding effect on principal building is found to be significant when the heights of interfering buildings range from 0.75 to 1.5 of the height of the principal building. The along-wind force of the downstream principal building reduced to zero when the upstream interference building of height ratio more than one was two to three times the building breadth away from the principal building.