Turbine engine combustor having a tunable acoustic damper

A turbine engine comprising:

• a compressor section, a combustion section downstream of the compressor section, and a turbine section downstream of the combustion section, the combustion section having a combustor comprising:
• a wall defining a combustion chamber;
• and
• an acoustic damper comprising:
• a housing in fluid communication with the combustion chamber through an opening provided in the wall of the combustion chamber, the housing mounted to the combustor via an armature, the housing defining a cavity and having a lateral wall, one or more neck holes in fluid communication with the combustion chamber, and one or more purge holes provided within the lateral wall of the housing, the one or more neck holes being provided on a face plate of the housing facing the combustion chamber;
• and
• a mechanism configured to vary a damping acoustic frequency of the acoustic damper via a piston moving through the armature to align with an acoustic frequency of acoustic vibrations generated in the combustion chamber to attenuate an acoustic instability within the combustion chamber and the one or more purge holes are provided between the armature and the face plate.