On Aircraft Lift and Drag Reduction Using V Shaped Riblets

Abstract

Reducing drag during take-off and nominal (cruise) conditions is a problem of fundamental importance in aeronautical engineering. Existing studies have demonstrated that v-shaped symmetrical riblets can effectively be used for turbulence control, with those with dimensionless depth h + = 15 and dimensionless width s + = 15 having the best drag reduction effect. In the present study, experimental tests have been conducted considering two models of the same size, one with smooth surface, the other with v-shaped riblets of the h + = 15 and s + = 15 type. The results show that for an angle of attack in the 8°~20°range (take-off stage), the maximum lift coefficient can be increased by 22%. For angle of attack between 8°and 14°, a drag reduction effect can be produced using riblets, which increases with the Reynolds number, leading to a decrease in the drag coefficient maximum of 36%. Flow visualization experiments have been carried out by means of Laser Induced fluorescence.

NACA 2412 Drag Reduction Using V-Shaped Riblets

“…Therefore, the V-shaped riblets were placed at the midsection of the wingspan, ranging from the 0.3C to 0.95C chord position. However, this did not improve the lift coefficients as expected (shown in Figure 10) due to variations in the height, spacing between the riblet tips, utilization of lower stream velocities, and riblet dimensions when compared to the referenced literature [51]. As a result, a change was made by relocating the riblets from midspan to three different positions, as depicted in Figure 3 under the computational design section.…”

“…This reduction in drag can be attributed not only to a decrease in turbulent friction but also to the mitigation of the separation area and otherwise smooth trailing section of the object [50]. Several studies demonstrate that symmetrical V-shaped riblets have the capability to enhance lift [51]. Therefore, the V-shaped riblets were placed at the midsection of the wingspan, ranging from the 0.3C to 0.95C chord position.…”

“…As a result, a change was made by relocating the riblets from midspan to three different positions, as depicted in Figure 3 under the computational design section. Identical meshing and analysis approaches were Several studies demonstrate that symmetrical V-shaped riblets have the capability to enhance lift [51]. Therefore, the V-shaped riblets were placed at the midsection of the wingspan, ranging from the 0.3C to 0.95C chord position.…”