Fluid handling structure and lithographic apparatus

A device manufacturing method comprising:

• projecting a patterned beam of radiation onto a substrate, wherein the patterned beam of radiation is passed through a region of immersion fluid;
• confining the immersion fluid to the region using a fluid handling structure, wherein the fluid handling structure comprises a gas knife system;
• and
• generating a gas knife radially outward of the region, using the gas knife system, wherein the gas knife contributes to the confining step, and wherein the gas knife system comprises passages each having an exit, the passages comprising a plurality of first passages having a plurality of corresponding first exits, and a plurality of second passages having a plurality of corresponding second exits, wherein at least one first passage and at least one second passage are configured such that the stagnation pressure of gas exiting the first exit is greater than the stagnation pressure of gas exiting the second exit, and the plurality of first passages and the plurality of second passages are intermingled and arranged in a line such that the first exits and the second exits form a side of a shape in plan view.