Analysis and prediction of supersonic heated jet noise in axisymmetric air jets

Heated jet flows introduce a number of interesting and peculiar features of jet noise spectrum that have not been fully understood or indeed, self-consistently explained. One of these features is the apparent quietening of supersonic jets at high jet temperature ratio. This aspect of jet noise remains an important area of research not least because understanding any kind of mechanism of jet noise reduction will ultimately aid noise abatement strategies. In addition however the fact that the quietening owes its existence to a purely fluid mechanical means is more reason to understand and develop rational mathematical models to explain it. On the other hand, for low subsonic acoustic Mach number jets, an increase in temperature produces an increase in sound. The main purpose of this Ph.D. project is to utilize the in-house codes at Mississippi State University to map out the turbulence structure across the range of acoustic Mach number and jet temperature ratio. After which we shall use this information within an acoustic analogy model for the far field noise spectrum.

The Ph.D. student will be part of collaborative team of researchers and academics from Mississippi State University and the NASA Glenn Research Center. During the second year of study, the student will be based at Mississippi. The work will involve Computational Fluid Dynamics (CFD) of jet flows using Large Eddy Simulations as well as aero-acoustic modelling using various Applied Mathematical techniques.