Recent progress in flow diagnostics techniques and aeroacoustics at NAL

Venkatakrishnan, L (2009) Recent progress in flow diagnostics techniques and aeroacoustics at NAL. In: National Conference on Wind Tunnel Testing (2009-IT10), 12-14 Mar 2009, IISc., Bangalore.

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Abstract

The development of new flow diagnostic tools to address increasingly specific and complex questions of flow physics in aerospace flows is enormously challenging. The chief constraints are that these tools must be non-intrusive to the flow, place no overheads on tunnel testing time and yet deliver data that can e used for understanding or design. In the Experimental Aerodynamics Division at NAL, work has resulted in the development and extension of several new and novel ideas in flow. The application of these techniques to complex fluid relevant to the country's aircraft and spacecraft program has resulted in improved understanding. NAL has extended the Pressure Sensitive Paint (PSP) technique to yield surface pressure data on complex aircraft configurations. The Particle Image Velocimetry (PIV) technique is being applied to a variety of flows from subsonic to supersonic to obtain two and three component velocity fields. NAL has developed capability to obtain density in any plane of a flow with minimal hardware using tomographic algrotithms with a novel quantitative Schileren technique (Background Oriented Schlieren). The current state of these techniques is summarized with case studies. Aeroacoustics of high-speed jets has become an important area of research in the last decade to address issues such as aircraft certification, community and cabin interior noise and launch vehicles loads. There is now significant effort underway to reduce the noise from high speed jets by employing both passive and active flow control. Understanding of aeroacoustics involves addressing certain fluid dynamic issues like investigation of jet mixing, role of coherent structures in jet development, noise generation and the interaction between shock waves and coherant structures. In order to facilitate this, the recently commissioned Jet Aeroacoustics Research Facility (JARF) at EAD, NAL, enables comprehensive investigation of jet aeroacoustics with its capability for both flow and acoustic measurements. This design and development of this facility, which is an advanced aeroacoustic test bed to facilitate both existing and future national programs and basic research on jet noise is described in detail.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: Aeroacoustics;Particle image velocimetry (PIV);Tunnel testing
Subjects: AERONAUTICS > Aerodynamics
Division/Department: Experimental Aerodynamics Division
Depositing User: Ms. Alphones Mary
Date Deposited: 25 Aug 2009
Last Modified: 24 May 2010 09:56
URI: http://nal-ir.nal.res.in/id/eprint/5169

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