• 作者： 洪儒珍; 潘海林
• 作者服務機構： 美國阿拉巴馬大學機械與航太工程學系; 中國北京航空航天部北京控制工程研究所
• 中文摘要： 當衛星在軌道移動時，與衛星具有相對運動之流體均受到由地球重力梯度所引起加速度之作用。這加速度足以引發衛星流體系統之搖動波。同時，由衛星軌道上大氣之擾動引發之阻力、背景剩餘重力、以及衛星姿態控制、發動機震動、推進劑之點火、太空員的走動所造成的擾動等，亦足以激發衛星流體系統的搖動波。本文提出重力梯度與重力幌動加速度加諸於在軌道之軌道衛星流體系統之數學模式。由於重力梯度僅能在固定於衛星座標之非慣性系模式加以運算，因此數學模式由尋常的慣性系座標轉換成非慣性系座標。在此狀況下之初期和邊界條件亦詳加推導。在舉例方面，本文採用重力探測－B衛星（Gravity Probe-B Spacecraft）為例，說明其數值計算及物理意義。
• 英文摘要： The mathematical formulation of sloshing dynamics activated fluid systems driven by an asymmetricgravity gradient and gravity jitter accelerations, in particular, the effect of surface tension on partially-filled rotatingfluids in an orbital spacecraft dewar tank under microgravity, have been investigated. As the spacecraft movesalong an orbit, any fluid capable of motion relative to the spacecraft is subject to the acceleration that arises fromthe gravity gradients of the Earth. The interaction between the particle mass of fluid and the spacecraft mass dueto gravity gradient acceleration is capable of excitation of slosh waves in fluid systems. Meanwhile, the sourcesof residual acceleration of gravity jitter ranging from atmospheric drag on the spacecraft, to background gravity,spacecraft attitude motions arising from machinery vibrations, thruster firings, crew motions, etc., are also capableof the production of sloshing dynamic fluctuations in spacecraft fluid systems. Gravity gradient acceleration, inparticular, can only be calculated based on a non-inertia frame of spacecraft bound coordinates. Thus, the coordinatesystem will be transformed from an ordinary inertia frame coordinate to a non-inertia coordinate. Detailed initialand boundary condition formulations applicable to sloshing dynamics are discussed. A realistic example of sloshingdynamics activated fluid system disturbances applicable to a full-scale Gravity Probe-B spacecraft driven by a gravitygradient and jitter accelerations on the orbital conditions is given to illustrate execution of the mathematicalformulation. This mathematical formulation of orbital accelerations induced slosh wave excitation in on-orbitspacecraft fluid systems can greatly enhance our basic understanding of spacecraft control and the guidance ofdynamic systems.
• 中文關鍵字： gravity gradient acceleration; gravity jitter acceleration; orbital spacecraft; fluid systems; sloshing dynamics; bubble oscillations; spacecraft control; microgravity
• 英文關鍵字： --