Computation of sound in a simplified HVAC duct based on aerodynamic pressure

Curle’s analogy provides a solution to Lighthill’s equation when solid boundaries are present, and characterizes these boundaries as dipole sources. It can be shown that Curle’s dipoles can be used to define appropriate boundary conditions of a boundary value problem of the Helmholtz equation. This is advantageous from a modeling perspective, because the resulting numerical problem does not require volume-distributed sources to characterize the sound production. In this work, this approach is applied to compute the sound generated by an internal flow and radiated to the exterior. The noise produced by a simplified HVAC duct is computed, and compared to experimental data available in the literature in order to assess the accuracy of several numerical techniques. Specific aspects related to the modeling of interior/exterior problems are investigated.