Analysis of flexible baffles for damping tank sloshing.
Damping of liquid oscillations in cylindrical tanks, determining rigid and flexible baffle loss coefficients, baffle efficiency and maximum bending stress
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Damping of liquid oscillations in cylindrical tanks, determining rigid and flexible baffle loss coefficients, baffle efficiency and maximum bending stress
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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Investigation of forced vibration characteristics of unbaffled and baffled spherical tanks partially filled with liquid
Harmonic analysis of pressure data for solid and perforated baffle plates of fuel tanks
Annular baffle for damping liquid oscillations in partially filled cylindrical tank
Vibrational characteristics of large liquid propellant space vehicle
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The mercury propellant tank system developed for use with solar electric propulsion was studied to analytically determine the resonant frequencies of the tank system and compare them with the anticipated control natural frequency of the spacecraft. The system consisted of a stainless steel spherical shell and a hemispherical elastometric diaphragm. The major analytical tool used was the NASTRAN program. Six mathematical models were developed. Resonant frequencies for six harmonics were obtained for each of the six models considered. The results show that the lowest resonant frequency for the tank system is about an order of magnitude greater than the anticipated control frequency of the spacecraft.
The mercury propellant tank system developed for use with solar electric propulsion was studied to analytically determine the resonant frequencies of the tank system and compare them with the anticipated control natural frequency of the spacecraft. The system consisted of a stainless steel spherical shell and a hemispherical elastomeric diaphram which separates the mercury propellant and the gaseous nitrogen pressurant. The major analytical tool used was the NASTRAN program. Six mathematical models, which represent various amounts of mercury in the tank system were developed. Resonant frequencies for six harmonics were obtained for each of the six models considered. The results show that the lowest resonant frequency for the tank system is about an order of magnitude greater than the anticipated control frequency of the spacecraft.
An experimental study was conducted to provide data for evaluation of the parameters for an analytical mechanical model representation of liquid/interface dynamics in the TDRSS propellant tanks. Models were developed for two liquid-under ullage (forward tank) configurations and for one liquid-over-ullage (aft tank) configuration. However, additional test runs were conducted with liquids of different densities in both cases to allow separation of bladder stiffness and gravity effects under various simulated steady acceleration conditions. Both static and dynamic parameters are evaluated to provide a good prediction of observed results.
The Get Away Special (GAS) G-025, which flew on shuttle Mission 51-G, examined the behavior of a liquid in a tank under microgravity conditions. The experiment is representative of phenomena occurring in satellite tanks with liquid propellants. A reference fluid in a hemispherical model tank will be subjected to linear acceleration inputs of known levels and frequencies, and the dynamic response of the tank liquid system was recorded. Preliminary analysis of the flight data indicates that the experiment functioned perfectly. The results will validate and refine mathematical models describing the dynamic characteristics of tank-fluid systems. This will in turn support the development of future spacecraft tanks, in particular the design of propellant management devices for surface tension tanks.
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A coupled strongly implicit solution strategy for unsteady three-dimensional free surface flows has been developed based on an artificial compressibility formulation for the incompressible Navier-Stokes equations. A pseudotime term has been used in the continuity equation to permit time accurate calculations to be achieved. The scheme appears capable of tracking the free surface reasonably accurately inside a partially-filled spherical container undergoing a general rotating motion characteristic of that experienced by a spin-stabilized satellite. Five different free surface calculations have been presented. Some of the results exhibit an interesting Reynolds number dependent oscillatory behavior which is believed to be physical although no experimental results appears to be available for verification to date.
The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations, in particular the effect of surface tension on partially-filled rotating fluids (cryogenic liquid helium and helium vapor) in a sub-scale Gravity Probe-B Spacecraft propellant dewar tank imposed by time-dependent various directions of background gravity environment have been investigated. Results show that lower frequency gravity jitter imposed on the time-dependent variations of the direction of background gravity induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid-vapor interface geometry than that made by the higher frequency gravity jitter. Furthermore, the greater the components of background gravity in radial and circumferential directions will provide a greater contribution in driving more to the increasing amplitude and degrees of symmetry of liquid-vapor interface profiles which, in turn, modify the disturbance of moment of inertia and angular momentum of spacecraft.
The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations is investigated focusing on the surface tension effect on partially filled rotating fluids in a sub-scale gravity probe-B spacecraft propellant dewar tank. Data obtained revealed that the lower frequency gravity jitter imposed on the time-dependent variations of the background gravity direction induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid-vapor interface geometry than that caused by the higher frequency gravity jitter. It is also found that the greater the components of background gravity in radial and circumferential directions the greater the contribution to driving more toward increasing amplitude and degrees of asymmetry of the liquid-vapor interface profiles, which in turn modify the disturbance of moment of inertia and angular momentum of spacecraft.