Mode selective transfer of energy from sound propagating inside circular pipes to pipe wall vibration

Experimental results are presented which show a mode selective transfer of energy from sound propagating inside a circular pipe to pipe wall vibration. The experiments utilize broadband noise generated by flow through a restriction in the plastic (PVC) pipe. For each higher acoustic duct mode, the energy transfer occurs in a narrow frequency band located slightly above the higher-mode cut-on frequency. A match in axial phase velocity between the higher acoustic duct mode and a compatible pipe wall vibrational mode is proposed as the mechanism for the energy transfer. Theoretical predictions for the frequency at which the axial phase velocity match occurs show good agreement with the experimental results.