A lobe mixer (22) used in jet engines, is provided with diameter expansion
portions (22a) in which the diameters gradually increase in the downstream
direction, in which adjacent diameter expansion portions have different
diameters from each other, and which guide the core gasses that flow along
the inner sides of the adjacent diameter expansion portions, peripherally
outwards at different angles. Thus, the gasses are mixed without the
thrust of the jet engine being reduced, and the noise of the jet is
reduced.
