Effect of after-body length on peak pressure distribution over tall buildings with corner modifications

The paper presents the wind tunnel investigation results aimed to quantify the impact of the after-body length on peak pressure distributions over the corner modified building models. A total of twenty-six scaled building models are evaluated. Tested building configuration comprises two base models (square and rectangular) and twelve modifications on each base model. Three proportions (10%, 20%, and 25% of the width) of the most frequently adopted corner modifications, namely, corner roundness, chamfering, recession, and double recession, are evaluated. Experimental results are presented in the form of non-dimensional pressure coefficients, and region-specific evaluation of peak pressures is performed over three regions (i.e., windward wall, sidewall, and inside modification zone) for all the models. Results over the sidewall region show that the beneficial effect (reduction in the magnitude of suction) due to an increase in the after-body length, generally observed in the case of the base models, also exists for corner-modified models. However, the most crucial and counter-intuitive takeaway from this study is that the severity of the suction inside the modification zone for rectangular models is aggravated considerably compared to the corresponding square models. A typical comparison at the mid-height level shows that this increase in the negative peak pressure coefficients is in the range of 10% to 34% for all the considered models. Furthermore, the variation of the highest negative peak pressure coefficient along the height of building in the critical regions (inside modification zone and sidewall region) are analyzed in detail for all the considered building models. • Increased after-body length reduces peak suction on sidewalls of corner-modified tall buildings. • Rectangular tall building models exhibit 10–34% higher peak suction inside corner modification zones than square models. • Beneficial suction reduction on sidewalls is pronounced only at mid-height (0.3H–0.8H).