Acoustic modeling of fricative /s/ for an oral tract with rectangular cross-sections

Abstract

Fricative /s/ is known to be pronounced by jet generation and subsequent impact on walls of the oral cavity. The prediction of acoustic characteristics of /s/ is an ongoing research topic due to the aeroacoustic nature of the sound source. In this study, acoustic characteristics are modeled using the multimodal theory with monopole and dipole sources positioned in the oral tract waveguide. The oral tract geometry of fricative /s/ was simplified by concatenating rectangular channels whose cross-sectional areas and vertical height are derived from medical imaging. To validate the model accuracy, transverse and sagittal directivity patterns (49 cm every 15 •) were measured for flow

Numerical investigation of effects of incisor angle on production of sibilant /s/

“…To determine the relationship between the positions of the velocity fluctuations, i.e., the assumed aeroacoustic sound sources, and the far-field SPL spectra, instead of the base simulation with constant velocity inlet from the throat, the acoustic simulations with acoustic monopole sources were conducted for the 0° and 30° cases. In the previous acoustic studies, monopole to quadrupole sound sources were used to emulate the sound generated by the turbulent flow 29 , 30 . Therefore, for the simplicity, the monopole sources composed of white noise were applied in the current study at Point 1 (49.1, − 8.4, − 7.7) and Point 2 (58.5, − 7.7, − 4.5), which corresponded to the positions of maximum velocity fluctuations at 10 kHz for both models.…”