Enhancement of energy and Q-factor of a nonlinear resonator with an increase in its losses

Resonant properties of a nonlinear dissipative layer excited by a vibrating boundary: Q-factor and frequency response

“…33 This method was realized experimentally, 34 but its possibilities are being studied up to now. 35,36 Quite another approach to enhance Q with no changes in the design of the resonator was suggested in Ref. 37.…”

Finite amplitude standing waves in resonators terminated by a general impedance

“…This issue has been addressed in Ref. 5 where a steady-state approximate solution of Eq. (38) for a perfect fluid was presented.…”

“…In this case, the selective absorber makes the second-harmonics generation weak and, therefore, reduces the cascade of the nonlinear transfer of energy upward over the spectrum. 5 Assuming f ðxðs À L=c 0 ÞÞ ¼ v m sinðxsÞ and the second-harmonics absorber, then we can replace the last term on the left-hand side of Eq. (29),…”

“…Another method uses a selective absorber in the cylindrical resonator. 5 The absorber attenuates the second harmonics, which develops in the course of cascade processes as a result of nonlinear interactions. The total suppression of the second harmonics brings about an interruption of the cascade processes and the acoustic energy is accumulated in the first harmonics.…”

“…In Ref. 5, the approximate solution of a modified inhomogeneous Burgers equation, which models the method based on the selective absorption, was presented. However, this approximate solution is rather inaccurate and, in addition, it is limited only to the case of perfect fluids.…”