Shock-Shock Interaction over a Hemisphere in Hypersonic Flow Nadia Kianvashrad ∗ and Doyle Knight † Rutgers - The State University of New Jersey, New Brunswick, New Jersey 08903, USA The interaction of an impinging oblique shock with a bow shock in front of a hemisphere in Mach 14.6 flow is simulated using a C ++ code. The experiments were performed at the 48-inch Shock Tunnel at Calspan University of Buffalo Research Center (CUBRC). Due to the uncertainty in the exact location of the impinging shock, several calculations are required to achieve the correct location by matching the location of computational peak surface heat transfer and pressure with the corresponding experimental location. Two such calculations are presented in this paper. Both of the simulations show an Edney III type interaction. For the first simulation, the shock-shock interaction is statistically stationary with a dominant Strouhal number of 0.348. The time averaged flowfield shows general agreement with experimental surface pressure and heat transfer; however, the location of peak values are displaced from the experimental peak values by three degrees. The second calculation which has the correct prediction of peak location is not statistically stationary and displays several dominant Strouhal numbers. I. Introduction T he interaction of shocks in hypersonic flows creates a region of high surface pressure and heat transfer. The localized high aerothermodynamic loading may cause structural failure. An example of structural failure is the damage to the pylon mounted beneath the fuselage of flight 2-53-97 of the X-15A-2 as shown in Figure 1. This damage was due to the high heat transfer of a shock-shock interaction over the pylon which was later categorized as an Edney IV interaction. 1 Figure 1. Damaged pylon of X-15 2 Shock-shock interaction can occur in the junc- tion of the wing-fuselage, tail-fuselage, and at con- trol surfaces. Inlets of air breathing engines are also subjected to shock-shock interaction. The compres- sion ramp on the inlet creates a shock which inter- acts with the bow shock that forms in front of the engine cowl. Glass et al. 3 reported an example of a shock-shock interaction in the X-30 engine. Edney 4 categorized the shock-shock interaction of an oblique shock and a bow shock into six groups. The location at which the oblique shock interacts the bow shock determines the shock-shock interaction type. Among these six types of interaction, type III and IV are subjected to higher surface pressure and surface heat transfer. A Edney III type interaction is characterized by a shear layer which interacts with * PhD Candidate, Department of Mechanical and Aerospace Engineering, AIAA Student Member. Email: nadiakian- vashrad@gmail.com † Professor, Department of Mechanical and Aerospace Engineering, AIAA Member. Email: doyleknight@gmail.com Copyright c  2019 by Nadia Kianvashrad and Doyle Knight. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission. 1 of 17 American Institute of Aeronautics and Astronautics Downloaded by Doyle Knight on January 11, 2019 | http://arc.aiaa.org | DOI: 10.2514/6.2019-0890 AIAA Scitech 2019 Forum 7-11 January 2019, San Diego, California 10.2514/6.2019-0890 Copyright © 2019 by Nadia Kianvashrad and Doyle Knight. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. AIAA SciTech Forum