Flow restrictors for aircraft inlet acoustic treatments, and associated systems and methods

An aircraft inlet system, comprising:

• an inlet flow surface positioned adjacent to an inlet flow path and having multiple openings;
• an acoustic treatment positioned adjacent to the inlet flow surface, the acoustic treatment having multiple cells in fluid communication with the openings in the inlet flow surface;
• means for collecting liquid entering the acoustic treatment through the multiple openings;
• means for at least restricting a flow of air through the acoustic treatment and to the inlet flow path through the multiple openings.

A method for operating an aircraft inlet, comprising:

• drawing air through an aircraft inlet to an aircraft engine;
• attenuating noise in the inlet by allowing acoustic signals to pass through apertures in a surface of the inlet to an acoustic treatment;
• collecting moisture from the acoustic treatment in a fluid passage;
• removing the moisture through an exit aperture of the fluid passage;
• and
• at least restricting a flow of air from the exit aperture through the fluid passage and into the inlet through the apertures.