Systems and methods for reducing noise from jet engine exhaust

An aircraft jet engine with a longitudinal axis comprising:

• a wall surrounding a gas stream that is ejected at a downstream end of the wall along the longitudinal axis;
• plural ducts distributed around the periphery of the downstream end of the wall and each comprising a terminal portion comprising an outlet opening, each duct configured to eject a fluid jet through its outlet opening,
• wherein the ducts are configured to eject fluid jets more or less parallel to each other, each fluid jet ejected through the corresponding outlet opening forming a lateral angle with the longitudinal axis along a projection view in a plane containing the longitudinal axis, and
• wherein the ducts include primary ducts that are spaced apart from each other and the ducts include at least one secondary duct added adjacent and parallel to each primary duct to form clusters of ducts having a same orientation.