Most whistles operate due to a feedback mechanism between flow instability and acoustics. The interaction between aerodynamics and acoustics is termed as aeroacoustics. Whistles (e.g. steam kettle whistle, sport whistles, samba whistles, police whistles etc) are empirically derived and the theory behind the whistling mechanism is not well understood. This project is mainly experimental and involves manufacturing a model whistle (in Perspex to facilitate flow visualisation. The type of whistle selected would depend on the interest of the student) and making aerodynamic and acoustic measurements that would lead to a simple physics-based model. A physical understanding of such flows would help understand other whistling mechanisms that are of practical importance (e.g. whistling in pipes with cavities and junctions, automobile exhausts, etc).
Relevant IIB modules: 4A15, Aeroacoustics (Michaelmas 2012) and 4A10, Flow instability (Lent 2013)