Flow control of shear layers over 2-D cavities using pulsed jet and aero-optical analysis

Yan Tan, Ramesh Agarwal, William Bower, Andrew Cary

Research output: Contribution to conferencePaperpeer-review

6 Scopus citations


Prediction and control of optical wave front distortions and aberrations in a high energy laser beam due to interaction with an unsteady highly non-uniform flow field is of great importance in the development of directed energy weapon systems for an Unmanned Combat Air Vehicle (UCAV). Unsteady shear layer over the weapons bay cavity is the primary cause of this distortion of optical wave front at the time of ejection of laser guided weapon from the cavity. The large scale vortical structure of this shear layer can be significantly broken or eliminated by employing an active flow control technique such as pulsed blowing. In this paper, we first perform numerical simulations to study the active flow control of cavity shear layer by employing a pulsed jet at the leading edge of the cavity. Numerical simulations are performed, with and without active flow control, for free stream flow of Mach 0.6 past 2-D rectangular cavities of aspect ratio L/D = 2 and 4, where L and D are the width and the depth of a cavity respectively. The vorticity, velocity and pressure fields are computed and the comparisons are made between the flow fields without and with active flow control. Comparisons are also made with limited flow field results available in the literature for these cases. The effect of pulsed blowing on buffet loading on the downstream face of the cavity is also computed. Aero-optical analysis is developed and applied to both the numerical simulation cases. Index of refraction and optical path difference (OPD) are compared for flow fields without and with pulsed jet. Unfortunately no aero-optical measurements are available for these cases. Therefore the flow field computations and aerooptical analysis of a L/D=4 cavity flow field for free stream flow of Mach 0.5 and 0.7 without and with steady blowing (applied at the leading edge) are performed, since the aero-optical data is available for these cases from the University of Notre Dame. Numerical results for OPDrms at half depth along the width of the cavity and free stream Mach number above the cavity are compared with the experiment data.

Original languageEnglish
Number of pages21
StatePublished - 2004
Event42nd AIAA Aerospace Sciences Meeting and Exhibit - Reno, NV, United States
Duration: Jan 5 2004Jan 8 2004


Conference42nd AIAA Aerospace Sciences Meeting and Exhibit
Country/TerritoryUnited States
CityReno, NV


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