Amirkabir University of Technology AUT Journal of Mechanical Engineering 2588-2937 1 2 2017 12 01 Computational Investigation of Unsteady Compressible Flow over a Fixed Delta Wing Using Detached Eddy Simulation 219 232 2750 10.22060/mej.2017.12863.5455 EN H. Ansarian Malek Ashtar University of Technology, Tehran, Iran M. Hadidoolabi Malek Ashtar University of Technology, Tehran, Iran Journal Article 2017 05 07 Unsteady compressible flows over a stationary 60-degree swept delta wing with a sharp<br />leading edge were computationally simulated at different Mach numbers and moderate angles of the<br />attack. An unstructured grid, Spalart-Allmaras Detached Eddy Simulation turbulence model, and a<br />dual-time implicit time integration were used. Vortical flow structures associated with various freestream<br />conditions are displayed and their variations versus time are studied. Variations of flow field<br />parameters, such as u velocity component and pressure coefficient with the flow time are demonstrated<br />at several point probes in the flow field. A Power Spectral Density frequency analysis is performed for<br />such unsteady behaviours to identify the dominant frequencies which exist in each flow condition. The<br />frequency analyses show that low frequencies associated with vortex breakdown oscillation are the most<br />dominant frequencies in all cases where vortex breakdown occurs. Dominant frequencies associated with<br />helical mode instability are also present at the probes downstream of breakdown. Dominant frequencies<br />related to the shear layer instabilities were observed for the low subsonic regime. https://ajme.aut.ac.ir/article_2750_fc192b0c0d270dbf41870a63a8c76c2f.pdf