Study on a Generic Nonlocally Reacting Liner

For many applications (e.g., in aircraft engines), the cells of Helmholtz resonator liners are not solely locally reacting because drainage slots are cut into the side walls. However, for the design of liners, the resulting effects of such drainage slots are currently not taken into account. Therefore, this paper presents a study on the effects of liner-cell interaction. In the first part, experimental results for different slot configurations of a generic test object (the scaled liner cavity) are shown and discussed. The major result is an additional dissipation maximum caused by the cell interaction. Based on these findings, an empirical relation is derived incorporating geometrical parameters like the percentage open area ratio to predict the appearance of the additional maximum.