With an ideal assumption of inviscid, incompressible flow, a low speed flow passing a cylinder has no boundary layer (due to viscous effect) and the fluid completely attaches itself with the cylinder shape without any separation. For such ideal case, no wake turbulence is formed downstream and the streamlines' shape appears to be the same in the front and the rear sides of the cylinder. As the flow is symmetric streamwise, the pressures on the front and rear sides are equal and there is no drag force acting on the cylinder.