有限水域棒束附连水质量规律试验研究

Experimental research on the law of added masses of a group of cylinders in confined fluid

本文对一个水箱内不同位置插入试验棒的模型进行试验研究。试验包含对棒的水平激振试验和对基座的水平冲击试验两部分,试验得出棒各阶附连水质量与其在无限水域中各阶附连水质量的比例系数,激励垂直于边界时,棒距边界距离越大附连水质量越小,平行时影响不大;激振试验中激励与两棒轴线共面时,附连水质量随棒间距增大而减小,且随棒数增多而变大,垂直时影响不明显;冲击试验中因两棒做同相位振动,故共面时附连水质量随棒间距增大而增大,垂直时相反。随着距离进一步增大,上述所有状态最终都趋于无限水域中单棒附连水质量。

The added mass experiments of cylinders stimulating horizontally by an exciter and an impactor in a water cistern are introduced in this paper. The added mass coefficient(ratio of added mass in constrained fluid to that in infinite fluid) under test conditions is presented. The added mass decreases with the increase of the distance between the cylinders and the wall when the exciting force is perpendicular to the wall, yet the change is not obvious when the force is parallel with the wall. The added mass decreases with the increase of the distance between two cylinders when the exciting force is in plane of two cylinders’ axes, and the change is not obvious either when exciting force is perpendicular to the plane. However, the added mass increases with the increase of the distance between two cylinders of the same vibration phase when the impacting force is in plane of two cylinders’ axes, and the added mass decreases with the increase of the distance when the impacting force is perpendicular to the plane. With further increase of the distances, all the added masses approach the same value-the one of a single elastic cylinder in infinite water.