The Ohio State University

Abstract:

This talk reports findings from a systematic effort to predict far field noise from subsonic jets using the unsteady Favre-averaged Navier-Stokes equations. The ultimate goal is to be able to make reliable predictions of noise from jet engines with and without modifications to the nozzle trailing edge. Two types of jets, namely, hot and cold, have been considered. Calculations have been run for two Mach numbers - 0.75 and 0.9. Three-dimensional, compressible, turbulent, Favre-averaged Navier-Stokes equations are solved on a hybrid mesh with about 2 million cells. The near wall resolution inside the nozzle and the shear layer is such that the wall y+ is less than 10. Numerical predictions of aerodynamic quantities - both mean and fluctuating and aeroacoustic quantities for round nozzles are initially compared with experimental data available in the literature. Some possible measures for improving the predictions are then discussed. Results from nozzles with trailing edge modifications (chevrons) are presented next. Effect of varying the chevron penetration, angle and length are brought out. Comparison of the predictions with experimental data is also given.

Bio:

Prof. Babu received his and M.S and Ph.D in Mechanical engineering from the Ohio State University in 1989 and 1991. He was a Research Associate at the Ohio State University from 1991-1995. He joined the Ford Research Lab at Dearborn, Michigan in August 1995 and worked as a Technical Specialist till Nov. 1998. He joined the Faculty of Indian Institute of Technology Madras in Dec 1998. He has received the Henry Ford Technology Award in 1998 for his work on the development of a Virtual Wind Tunnel. He has four US patents and has authored two books. His research interests are simulation of high speed reacting flows, supersonic combustion, computational aeroacoustics, lattice Boltzmann method and high performance computing.

The seminar will be held in E100 Scott Laboratory and is hosted by Professor Seppo Korpela.