\ Shock Induced Noise In Imperfectly Expanded Jets

Shock Induced Noise In Imperfectly Expanded Jets

Bülent İmamoğu, PhD

Thermal systems design and Mechanical design engineer at Türkiye Teknoloji Merkezi (TTC)

Tarih ve Saat

4 Ekim 2017 - 12:00



First part of this presentation will summarize the dissertation work of Dr. Imamoglu, which is about screech noise in imperfectly expanded jets. The computational study helps better understand screech generation mechanisms and makes comparisons with available experiments. First, axisymmetric models are constructed for underexpanded jets of 25.4 mm diameter and Mach numbers of 1.19 and 1.43. Then, three dimensional (3D) models are computed for jets with Mach numbers of 1.43 and 1.80. The mathematical model consists of full Navier-Stokes equations in cylindrical coordinates, and large-eddy-simulation turbulence modeling. For spatial discretizations, a fifth-order, weighted essentially non-oscillatory (WENO) scheme is used. Time discretization is a third-order total-variation-diminishing scheme. This methodology does not require artificial viscosity or “tuning up” of parameters. Computed screech frequencies match experimental results. Second part of the presentation will include examples from project work in TÜBİTAK MAM and TTC, namely the pneumatic rock breaking mechanism developed for Turkiye Taşkomürü Kurumu, and computation of convective heat transfer in the fan compartment of an airplane engine.

Bülent İmamoğu attended Kadıköy Anadolu Lisesi before joining Boğaziçi University where he received BS and MS degrees in Mechanical engineering in 1995 and 1998. He obtained PhD in Aerospace Engineering in Old Dominion University (USA) in 2004 with a dissertation on screech noise in imperfectly expanded jets. He worked in TUBİTAK Marmara Research Center, Chemistry Institute from 2006 to 2013. He took part as researcher and director in national and EU projects, helped design of pilot scale chemical plants and process equipment. Then he worked at TTC, joint engineering center of GE and TEI, between 2013 and 2017, as thermal systems design and mechanical design engineer, performing heat transfer, CFD, stress and life calculations.