1997 年 63 巻 610 号 p. 1861-1868
Three-dimensional nonlinear liquid motion in a rigid rectangular tank partially filled with liquid, in response to pitching excitation, is investigated. In the case that symmetric modes are dominant, the nonlinear ordinary differential equations governing the liquid surface oscillation are derived by applying Galerkin's method to the basic equations. It is confirmed that vertical excitation causes parametric excitation. In addition, it is noted that pitching excitation also causes parametric excitation when the pitching axis does not intersect the vertical line passing the center of the tank bottom. An experiment was conducted using a model tank. Good agreement was found between the theoretical and experimental results.