Study of the nonlocal active sound control with preservation of desired field in time domain

Abstract

In the active sound control, a domain is protected from externally generated noise via constructing secondary sound sources, which are called controls. These controls are applied on the boundary of the shielded domain. Apart from the external noise, a desired sound generated by interior sources should also be retained inside the shielded domain. However, it turns out it is a challenge to preserve the internally generated sound unaffected due to both the reverse effect of the controls on the input data and sparse distribution on the boundary. To take into account the reverse effect, an innovative algorithm based on nonlocal control is implemented in the time domain for the first time. Its real-time practical implementation may include preliminary tuning to the real surrounding conditions. A number of test cases are considered including external broadband noise and internal monochromatic desired sound. A sensitivity analysis is carried out with respect to some key design parameters such as density of sensors and controls as well as respective geometrical displacement from one another determined by the Hausdorff distance. It is demonstrated that the nonlocal control provides the noise attenuation level, which is not very sensitive to the presence of the desired sound.

Optimized nonlocal active sound control in frequency domain

“…In addition, the input field is not limited by the primary field. As demonstrated in [44] and [45], this kind of control is stable even in case a desired component is present.…”

“…The problem related to the fail of the local control in the presence of a desired sound component can be effectively resolved with the use of the nonlocal control [42,44,45].…”

“…A practical algorithm for real-time implementation of NASC is proposed in [42]. Zhou and Utyuzhnikov have recently realized this algorithm in both frequency and time domains in [44,45], respectively, and carried out numerical experiments including sensitivity analysis. In particular, it is shown that in the case of sparse distributions of the sensors and controls, the nonlocal control can provide much greater noise attenuation than the local control even if the primary field is supposed to be available.…”

“…In papers [44,45], the authors consider an uniform distribution of the sensors and controls to protect a cubic domain. Thereby, no attention is paid to the optimization of the number of sensors and controls apart from their total uniform reduction in the framework of the sensitivity analysis.…”