Investigation of Methods for the Alleviation of Supersonic Flow-Instability of a Pitot Air-intake

Merchant, Laxmikant and Ahmed, Sajeer (2003) Investigation of Methods for the Alleviation of Supersonic Flow-Instability of a Pitot Air-intake. Project Report. National Aerospace Laboratories, Bangalore.

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An experimental study was carried out on a 'D' shaped, convergent-divergent pitot intake duct with splitter plate and diverter height of 9.6mm (h/d = 0 .6) at a free stream Mach number of 1.6 in the 0.3m tunnel. Tests on the intake duct model have showed the occurrence of flow instability in the form of shock oscillations with a drop in total-pressure recovery when operating at moderate exit area ratio. The aim of this study was to get an improved understanding of the mechanism leading to flow instability and also to extend the range of stable-subcritical operation of the intake duct by introducing the methods to alleviate the flow instability. Based on the experimental results obtained for the above model configuration, two methods were proposed for the alleviation of flow -instability viz. increasing the length of splitter plate and, providing perforations on the splitter plate. Analysis of the results showed that increasing the splitter plate length has a positive effect on the alleviation of flow-instability (exit area shifted to lower value at which instability was observed for basic model configuration) accompanied with slightly reduced total-pressure recovery. Whereas, with perforated splitter plate, flow-instability was found to occur at higher exit area ratio accompanied with slightly improved total-pressure recovery.

Item Type: Monograph (Project Report)
Uncontrolled Keywords: Pitot intake, Supersonic flow-instability, Shock-oscillations, Alleviation, Exit area ratios
Subjects: AERONAUTICS > Aerodynamics
Depositing User: Smt Bhagya Rekha KA
Date Deposited: 01 Mar 2012 08:51
Last Modified: 01 Mar 2012 08:51

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