The effect of periodic ballonet jet exhaust on the stability of a tethered aerostat

Kannan, SM and Rao, GNV (1987) The effect of periodic ballonet jet exhaust on the stability of a tethered aerostat. In: 7th AIAA Lighter-Than Air Technology Conference, 17-19 Aug 1987, Monterey, United States.

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Abstract

Tethered aerostats operating under wide range of altitudes and atmospheric pressure conditions employ ballonets within the hull filled with air. These ballonets exhaust the air into the atmosphere whenever necessary to maintain the difference between the atmospheric pressure and the internal pressure within a desired range. Assuming that the air exhaust is made periodic, studies are made on the effect of the periodic jet force and the resulting pitching moment on the response of the aerostat system. In the first phase, the stability of the system is studied by analyzing the eigenvalues and eigenvectors. The result shows that the aerostat system is unstable in the windspeed range of 0-15 fps and stable in the windspeed range of 15-100 fps. When the system is subjected to a suitable periodic forcing from the exhaust jet, it is observed that it is not only possible to extend the stability boundary of 15 fps down to typically 5 fps, but much more interestingly, there exist forcing periods of the exhaust jet which render the system completely stationary.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: Stability;Exhaust systems;Barometric pressure;Eigenvalues; Boundaries;Hulls (structures);Internal pressure;Aircraft Stability;Airships;Jet Exhaust;Wind velocity
Subjects: AERONAUTICS > Aircraft Stability and Control
Division/Department: Experimental Aerodynamics Division, Other
Depositing User: M/S ICAST NAL
Date Deposited: 12 Oct 2006
Last Modified: 24 May 2010 09:51
URI: http://nal-ir.nal.res.in/id/eprint/2976

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