Mean pressure distributions around a circular cylinder in the branch of a T-junction with/without vanes

The mean pressure distributions of a single circular cylinder in the branch of a T-junction with and without vanes are experimentally investigated in a low-speed wind tunnel. Experimental data of the circular cylinder in a straight duct are conducted to provide a benchmark. Mean pressure distributions of the circular cylinder are obtained at different positions along streamwise direction under the velocity ratio (R) ranging from 0.13 to 0.36. The detailed flow structure is observed with the help of numerical simulation validated by available experimental data. Two dimensionless parameters including correlation degree and amplitude ratio, are defined to analyze the pressure characteristics around the circular cylinder. It is found that, both the correlation degrees and the amplitude ratios increase totally with increasing distance of the circular cylinder away from the interface of the T-junction with/without vanes. Moreover, the pressure distributions around the circular cylinder in the T-junction without vanes show a double-peak type especially at a low velocity ratio, and thus present low correlation degrees compared with the benchmark, meanwhile, the amplitude ratios decrease from double to half of the benchmark level. Whereas, the pressure distributions around the circular cylinder in the T-junction with vanes show good agreement with the benchmark at a high velocity ratio. The flow structures obtained from simulation results reveal that the velocity distributions in the T-junction with vanes are more uniform than those without vanes so that the pressure distributions around the circular cylinder are much closer to the benchmark. The results would be helpful for designing the ventilation and heat transfer equipment used in high speed train.