International Journal of Applied Mechanics Vol. 8, No. 4 (2016) 1650047 (18 pages) c  World Scientific Publishing Europe Ltd. DOI: 10.1142/S1758825116500472 Three-Dimensional Passive and Active Control Methods of Shock Wave Train Physics in a Duct Reza Kamali ∗ , Seyed Mahmood Mousavi and Danial Khojasteh School of Mechanical Engineering Shiraz University Shiraz 71936-16548, Iran * rkamali@shirazu.ac.ir Received 16 September 2015 Revised 21 February 2016 Accepted 22 February 2016 Published 24 June 2016 In the present work, the physics of a three-dimensional shock train in a convergent- divergent nozzle is numerically investigated. In this regards, the Ansys-Fluent Software with Algebraic Wall-Modeled Large-Eddy Simulation (WMLES) is used. To estimate precision and errors accumulation we used the Smirinov’s method; fine flow structures are obtained via Laplacian of density called shadowgraph and the shock parameter is defined as multiplication of flow Mach number by the normalized pressure gradient, in which shock wave structures are visible distinctly. The results are compared with the experimental data of Weiss et al. [Experiments in Fluids 49(2) (2010) 355–365], in the same conditions including geometry, boundary conditions, etc. The results show that there is good agreement with experimental trends concerning wall pressure and center- line Mach number profiles. Therefore, the focus of the present study is an assessment of various flow control methods to change the shock structures. Consequently, we investi- gated the effects of passive (bump and cavity) and active (suction and blowing) control methods on the starting point of shock, shock strength, minimum pressure, maximum flow Mach number, etc. All CFD investigations are carried out by High Performance Computing Center (HPCC). Keywords : Shock train; WMLES model; bump; cavity; suction; blowing. 1. Introduction When a supersonic flow is decelerated to a subsonic flow in ducts, a complicated multiple shock waves system is produced, which is called shock train due to the shock waves and duct wall turbulent boundary layer interaction. The shock train forms in the isolator as a result of the adjustment to the pressure rise in the com- bustion chamber, as shown in Fig. 1. This figure demonstrates the schematic of the flow field in a constant cross-section area of an isolator. The flow compresses * Corresponding author. 1650047-1 Int. J. Appl. Mechanics 2016.08. Downloaded from www.worldscientific.com by WEIZMANN INSTITUTE OF SCIENCE on 07/11/16. For personal use only.