Flow around the open strut cavity has been investigated numerically. Open strut cavity is the cavity between two struts placed in tandem, along the flow. The simulation is done for the inlet Mach number of 2, with stagnation conditions of 3 bar and 300 K. Three different aspect ratios 4, 6 and 8 are simulated. Various flow features around the cavity are found to be similar to that of the wall mounted cavity. Pressure oscillations, inside the cavity, with a dominant mode at one of the Rossiter mode frequencies has been confirmed. The dominant mode is found to vary with aspect ratio of the cavity. Open strut cavity with aspect ratio of 8 behaved as closed cavity with a full bow shock in front of the trailing strut. Study of flow near the leading wall reveals the asymmetric nature of the flow in the symmetric configuration. The traveling compression wave is found to interact differently with the two shear layers, thus introducing asymmetry near the leading wall. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.