Air discharge device

An air discharge device comprising:

• a duct defining a flow passage through which a working air flow passes to be blown toward a discharge target;
• and
• a hole forming member defining an air discharge hole located at a downstream air side of the duct, as an air outlet from which the working air flow is blown out, wherein
• the hole forming member has a vortex generation structure configured to generate an auxiliary vortex having a vortex characteristic including a vortex rotation direction and a vortex axis direction, different from that of a lateral vortex generated by the working air flow at a downstream air side of the air discharge hole,
• the vortex generation structure is configured in the hole forming member such that the auxiliary vortex collides with the lateral vortex in a state where at least one of the vortex rotation direction and the vortex axial direction of the vortex characteristic of the auxiliary vortex is different from that of the lateral vortex,
• the vortex generation structure includes a plurality of auxiliary holes arranged along a peripheral edge portion of the hole forming member surrounding the air discharge hole, and the plurality of auxiliary holes are configured to generate a plurality of the auxiliary vortices different from the lateral vortices in at least one of the vortex rotation direction and the vortex axial direction,
• the peripheral edge portion of the hole forming member surrounding the air discharge hole includes a first edge and a second edge that are opposed to each other and extend with a predetermined distance therebetween, a third edge connecting one ends of the first edge and the second edge, and a fourth edge connecting the other ends of the first edge and the second edge,
• the first edge and the second edge configure a pair of long edges facing each other with a distance therebetween, smaller than a distance between the third edge and the fourth edge,
• the third edge and the fourth edge configure a pair of short edges facing each other with a distance therebetween, larger than the distance between the first edge and the second edge,
• the plurality of auxiliary holes are provided in the peripheral edge portion of the hole forming member surrounding the air discharge hole mainly on the edge sides of the pair of long edges such that the plurality of auxiliary vortices are less likely to be generated on the edge sides of the pair of short edges than on the edge sides of the pair of long edges, and
• an inner wall surface of each of the plurality of auxiliary holes from an upstream end to a downstream end is parallel with an inner wall surface of the duct separating an auxiliary air flow from the working air flow.