Streamlined Body:

• A streamlined body is defined as that body whose surface is aligned with the streamlines, when the body is placed in the flow.

• Thus, the body offers least resistance in terms of Pressure drag.

• Most of the drag experienced by the body is due to Viscous/Frictional drag, which depends on the surface area exposed to fluid.

• In this case, the separation usually takes place at the trailing edge.

Bluff body:

• A bluff body is defined as that body whose surface is not aligned with the stream-lines, when placed in the flow.

• Thus, the body offers lesser resistance in terms of Viscous/Frictional drag.

• There is very a large pressure drag, due to eddy formation after the body leading to a large wake region.

• Thus the pressure drag depends on the cross sectional area of the body rather than the surface area exposed.