Computational and neuro-fuzzy study of the effect of small objects on the flow and thermal fields of bluff bodies

The aim of the present study is to find computationally the optimum parameters that affect the drag reduction of bluff bodies using a small object (obstacle). These parameters include the size of the obstacle as well as the gap between the obstacle and the bluff body. Two- and three-dimensional bodies were investigated in turbulent flow fields. The research was focused on the cases of the rectangular-section obstacle. Four values of the obstacle size were studied, namely: 4\%, 10\%, 35\%, and 100\% of the size of the bluff body. The effect of the obstacle on the thermal field of the two-dimensional body was also studied. Comparisons were carried out with the available experimental measurements. A proposed neuro-fuzzy approach was used to predict the drag reduction of the entire system. Results showed that system drag reductions up to 62\% (two-dimensional flows) and 48\% (three-dimensional flows) can be obtained. Also, enhancement of the body cooling up to 75\% (two-dimensional flows) may be achieved. Generally, useful comments and suggestions are stated.