ملخص البحث :

Abstract. Experimental investigation of the flow and heat transferaround a heated cylinder in cross flow with and without usingwinglets has been carried out. Distribution of the static pressurecoefficients and Nusselt number and knowledge of the flow processesaround the cylinder without winglets enable as to form an idea of themechanism and pattern of the flow around the cylinder with winglets.The flow was in fully-developed turbulent flow with Reynoldsnumber range 0.72*104≤Re≤1.44*104. Four different shapes ofwinglets were used with different angles of attack (20, 26, 32) atdifferent locations ((Xm/D=0, 0.17, 0.3, 0.5), (Ym/D=0.57, 0.65, 0.72,0.8)). The results show that there is an effect of winglet shapes onheat transfer and pressure drop, and a better shape is a (trapezoidal(type 3)). For enhanced heat transfer from cylinder, heat transferincreases with increasing Reynolds number and angle of attack. Alsothe results show that the optimum position of winglet for enhancedheat transfer is (Xm/D=0.17 and Ym/D=0.65). The research showsthat heat transfer is enhanced as high as (14%) when winglets areused when compared with the case of a cylinder without winglets.There is also a slight increase in pressure drop.