DESIGN OF AN UNSTEADY AERODYNAMIC FORCE MEASUREMENT SYSTEM

Open Access
Author:
Lani, Shane William
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Michael H Krane, Thesis Supervisor
  • Patrick M Lenahan, Honors Advisor
  • Judith A Todd, Faculty Reader
Keywords:
  • Aeroacoustic Source
  • Force Transfer System
  • Fricative
  • Unvoiced Speech Sound Production
Abstract:
Finding the source of unvoiced speech sounds has been prevalently done by utilizing the radiated sound. The radiated sound would then be inverse filtered to obtain the source spectra. Aeroacoustic theory states that the source is the axial force on an obstacle, and for unvoiced speech sound production, the obstacle is the primary source. This study sought to obtain the source spectrum of unvoiced speech sound by using force measurements a method up until this point, which has not been used for studying unvoiced speech sound. The unvoiced speech sound is produced by a simple model of the human airway. The model is comprised of a constriction that forms a turbulent air jet and a rigid plate obstacle, downstream of the constriction, on which the jet impacts. The source spectrum was obtained by directly measuring the axial force of the obstacle resulting from the jet impaction. To measure the axial force, a force transfer system was designed and manufactured. Parametric studies of varying the jet velocity and path were utilized to generate the source spectra that were analyzed and compared to the results of Leonard (2010).