Supersonic open and closed cavity flows are investigated experimentally and computationally. Free stream Mach number of two is set. Schlieren imaging is used to visualise the flow behaviour showing stark differences between open and closed. Computational Fluid Dynamics (CFD) is used to simulate open cavity of flow with aspect ratio of 4. A rear wall treatment is implemented in order to pursue a simple passive control approach. Good qualitative agreement is achieved between the experimental flow visualisation and the CFD in terms of the expansion-shock waves system. The cavity oscillations are shown to be dominated by the first and third Rossister modes combining to high fluctuations of non-linear nature above the cavity rear edge. A simple rear wall treatment in terms of a hole shows mixed effect on the flow oscillations, RMS contours, and time history density fluctuations are given and analysed.<\/p>\r\n","references":"[1] Krishnamurty, K., \u00d4\u00c7\u00ffAcoustic radiation from two-dimensional rectangular\r\ncutouts in aerodynamic surfaces-, National Advisory Committee for\r\nAeronautics (N.A.C.A.) Technical Note 3487, 1955.\r\n[2] Tam, C. K. W. and Block, P. J. W., \u00d4\u00c7\u00ffOn the Tones and Pressure\r\nOscillations Induced by Flow over Rectangular Cavities-, Journal of\r\nFluid Mechanics, 89: 373-99, 1978.\r\n[3] Rockwell, D. and Naudascher, E., \u00d4\u00c7\u00ffSelf-Sustained Oscillations of\r\nImpinging Free Shear Layers-, Annual Review of Fluid Mechanics, 11:\r\n67-94, 1979.\r\n[4] Dellprat, N., \u00d4\u00c7\u00ffRossiters formula- A simple spectral model for a complex\r\namplitude modulation process?-, Physics of Fluids, 18, 7, 2006.\r\n[5] Tracy, M. B., Plentovich, E. B., Chu, J. and Langley Research Centre,\r\n\u00d4\u00c7\u00ffMeasurements of fluctuating pressure in a rectangular cavity in\r\ntransonic flow at High Reynolds numbers-, National Aeronautics and\r\nSpace Administration (NASA) Technical Memorandum 4363, 1992\r\n[6] Suponitsky, V., Avital, E. and Gaster, M., \u00d4\u00c7\u00ffOn three-dimensionality and\r\ncontrol of incompressible cavity flow-, Physics of Fluid, 17, 104103,\r\n2005.\r\n[7] Rowley, C. W., Colonius, T. and Basu, A. J., \u00d4\u00c7\u00ffOn self-sustained\r\noscillations in two-dimensional compressible flow over rectangular\r\ncavities. Journal of Fluid Mechanics, 455: 315-346, 2002.\r\n[8] Heller, H. H. And Bliss, D. B., \u00d4\u00c7\u00ffAerodynamically Induced Pressure\r\nOscillations in Cavities - Physical Mechanisms and Suppression\r\nConcepts-, Air Force Flight Dynamics Laboratory Technical Report\r\nAFFDL-TR-74-133, 1975.\r\n[9] William, D. R., Cornelius, D. and Rowley, C. W., \u00d4\u00c7\u00ffSupersonic Cavity\r\nResponse to Open-Loop Forcing-, Active Flow Control, 95: 230-43,\r\n2007.\r\n[10] Mohri, K. & Hiller, R. Computational and experimental study of\r\nsupersonic flow over axisymmetric cavities. Shock Waves, 21, 175-191,\r\n2011.\r\n[11] Delprat, N., \u00d4\u00c7\u00ffRossiter-s formula: A simple spectral model for a complex\r\namplitude modulation process?-, Fluids of Physics, 18, 2006.\r\n[12] Williams, D. R. and Rowley, C. W., \u00d4\u00c7\u00ffRecent Progress in Closed-Loop\r\nControl of Cavity Tones-, AIAA paper 2006-0712, 44th Aerospace\r\nSciences Meeting and Exhibit, Reno, Nevada, USA, 2006.\r\n[13] Punekar J., Avital EJ and Musafir RE, Computations of Nonlinear\r\nPropagation of Sound Emitted from High Speed Mixing Layers, Open\r\nAcoustics Journal 3, 11-20, 2010.\r\n[14] Hirsch C, Numerical computation of internal and external flows, vol. 2,\r\nComputational methods for inviscid and viscous flows, 1John Wiley &\r\nSons 1992.\r\n[15] Avital EJ, Musafir RE and Korakianitis T, Nonlinear Propagation of\r\nSound Emitted by High Speed Wave Packets, Journal of Computational.\r\nAcoustics in press.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 73, 2013"}