Compositional noise in nozzles with dissipation

We propose a physical model to predict indirect noise generated by the acceleration of compositional inhomogeneities in nozzles with viscous dissipation (non-isentropic nozzles). First, we derive quasi-one-dimensional equations from conservation laws multicomponent flows. Second, validate proposed experimental data available literature for binary mixtures four gases. Third, calculate nozzle transfer functions different Helmholtz numbers and friction factors, both subsonic supersonic flows with/without shock waves. show that have significant effect on generation noise, which mechanism is identified explained. Fourth, find semi-analytical solution path integrals, provides an asymptotic expansion respect number. Fifth, introduce compositional-noise scaling factor, applied quickly estimate knowledge only one single-component gas function. The approximation error less than $1\,\%$ . low-order accurate estimates insight into This opens up new possibilities accurately predict, understand, sound turbines.