EFFECTS OF G-JITTER ON FREE-SURFACE MOTION IN A CAVITY

Lateral g-jitter effects on free-surface deformation are studied numer ically in a zero-gravity environment for liquids in an open square con tainer. In order to allow for different contact-line conditions, a hys teresis parameter is incorporated into the SOLA-SURF finite difference scheme. The resonant frequencies of the free-surface motion are compu ted under various conditions. The resonant frequency is largest when t he contact line is fixed and decreases as it is allowed to move. The e ffect of viscosity reduces the resonant frequency or damps the resonan ce. The motion of the free surface and the amplitude of its deformatio n are investigated for two types of g jitter (sinusoidal and impulsive ) that are typically encountered aboard a spacecraft. It is shown that relatively large deformation occurs if the frequency of the periodic g jitter is near the resonant frequency. The impulsive g jitter excite s capillary waves with the resonant frequency, but they decay with tim e. Based on the computation and a scaling analysis, the amplitude of t he free-surface deformation is expressed in useful dimensionless form for those two types of g jitter.