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对以基本反对称振型振动的液柱在轴向加速度突然减小时的行为作了实验研究。为了得到时间最长为4.3秒的可控制低重力环境,采用了马歇尔宇宙飞行中心的落塔设备。试验在直径为6吋的圆柱形贮箱内进行,试验液体为石油醚,其接触角为零。试验的Bond数和Froude数变化范围(基于半径R)分别为12～100和0.03～22。得到了在推进剂控制系统设计中普遍适用的工程结果。同时,对于特定的S-ⅣB-203几何形状(带与不带防晃板和导流器)和入轨时的能量条件下的液体行为进行了估计。结果表明,在F_r=0.03～14.6和B_0=24～100范围内,最大液体振幅唯一依赖于Froude数。模拟不带防晃板的S-ⅣB-203液氢能量条件(F_r=19.3)产生晃动振幅放大,致使在低重力环境下有连续两个波达到S-ⅣB液氢箱模型的前底顶部。位于液面或稍高于液面的环形防晃板在减小晃动放大和阻尼低重力下的液体晃动都是很有效的。液体在S-ⅣB-203模型试验中的行为与AS-203入轨后观察到的非常相似。低重力环境下液体粘性对振动的衰减作用用对数衰减率描述,当初始振幅从0.6R至1.05R变化时,发现对数衰减率与振幅有关,随振幅增加而增加。大振幅晃动的初始阻尼比适用的关系式所预示的要大得多。液柱振动频率随所作用的加速度的变化而瞬时改变。加速度减小后第一周运动的周期测定值与Satterlee-Reynolds方程一致,在所试验的Bond数范围内相差不到8％。对于液体深度大于或等于R的情况,推导了液体重心最大移动量的经验关系式,它是Froude数的函数。
The behavior of a liquid column vibrating in the basic antisymmetric mode was suddenly reduced when the axial acceleration was reduced. To get a controllable low-gravity environment of up to 4.3 seconds, the Marshall Spaceflight Drop-tower was used. The test was carried out in a 6 "diameter cylindrical tank, the test liquid being petroleum ether, having a contact angle of zero. The range of Bond number and Froude number (based on the radius R) of the experiment were 12-100 and 0.03-22, respectively. The result of engineering which is generally applicable in the design of propellant control system is obtained. At the same time, the liquid behavior under specific energy conditions of the S-IVB-203 geometry (with and without anti-wobble plate and deflector) and on-orbit was evaluated. The results show that the maximum liquid amplitude depends on the Froude number only in the range of F_r = 0.03 ~ 14.6 and B_0 = 24 ~ 100. S-IVB-203 liquid hydrogen energy without shakes (F_r = 19.3) was simulated to amplify the amplitude of sloshing, resulting in two consecutive waves reaching the top of the anterior bottom of the S-IVB liquid hydrogen tank model in low gravity environment. Annular shakes at or slightly above the liquid level are effective in reducing rocking magnification and dampening liquid sloshing at low gravity. The behavior of the liquid in the S-IVB-203 model test is very similar to what was observed after AS-203 was in orbit. The effect of liquid viscosity on vibration attenuation in low gravity environment is described by the logarithmic decay rate. When the initial amplitude changes from 0.6R to 1.05R, it is found that the logarithmic decay rate is related to amplitude and increases with amplitude. The initial damping of large amplitude sloshing is much larger than the one indicated by the applicable relation. The column vibration frequency changes instantaneously with the applied acceleration. The period of the first week after acceleration decrease is consistent with the Satterlee-Reynolds equation, with less than 8% difference in the number of Bonds tested. For liquid depth greater than or equal to R, the empirical relation of the maximum movement of liquid center of gravity is derived as a function of Froude number.