A vacuum cleaner with a flexible head portion and combined suction and blowing mechanism to agitate debris. An external pressured air source is used to provide a source of pressured air for the blowing mechanism. The head portion has blowing and suction nozzles arranged such that the suction nozzles surround the blowing nozzles or vice versa. The blowing and suction nozzles may be in parallel rows and may have almost perpendicular trajectories. The blowing mechanism may be operated according to an alternating pulsing pattern corresponding to different blowing nozzle groups to create a repeating and bidirectional agitation effect onto stubborn debris in the area between the nozzle groups. The flexible head portion is formed by a grid of head portion units attached to each other by a joining mechanism. The flexible head portion has a concave shape in its relaxed state and can at least partially conform to irregular surfaces.