Study on the Effect of Two-Dimensional Helicopter V-buoy’s Way of Water Entry on Water Impact

To analyze the effect of the way of water entry on water impact, the FLUENT software was adopted to simulate a two-dimensional (2D) helicopter V-buoy’s free fall and forced fall at a constant velocity.Combining with the UDF program and the dynamic mesh model, the standard k-ε turbulence model was used and the VOF technique was adopted to capture free surface.The physical parameters such as velocity and force were calculated and compared with those results of boundary element method with good agreement obtained.It was found that the force of 2D V-buoy at a constant velocity was much greater than that in free fall motion.Meanwhile, the maximum pressure coefficients C p max in both cases were almost equal and the dimensionless water-entry depths y' corresponding to C p max were also similar.

SAVING WATER IS THE ONLY WAY FOR NORTHWEST CHINA TO SURVIVE

The most restrictive factor in the way of economic prosperity in China’s northwest lies in the lack of water resources.To seek countermeasures against this ages-old scourge of the arid hinterland,the CAS Division of Earth Sciences sponsored a workshop in Beijing on tapping water resources of Chinese northwest in March 1995 and decided to organize an expedition team of CAS members to investigate the water resources there.From August 23 to September 5,1995,the team carried out an on-the-spot survey along a 3,000-kilometre-long itiner-

数字特效技术与科幻电影叙事的耦合与断裂——电影《阿凡达》和《阿凡达:水之道》的对比分析

如今特效技术正以前所未有的速度进行更迭和升级。数字技术的发展,打破了传统叙事的边界,使得叙事呈现出前所未有的动态感与不确定性。本文以电影《阿凡达》和《阿凡达:水之道》的对比分析为研究切入口,旨在探究数字特效技术与电影叙事二者的互动关系。本文认为,《阿凡达》实现了技术与叙事的耦合状态,而续作《阿凡达:水之道》却让二者产生了断裂,致使口碑不佳。沿着科幻现实主义的路径,《阿凡达》以电影屏幕和数字技术为媒介,塑造了层次丰富的叙事内涵,引发关于技术媒介、技术化身和人类身体之间更复杂且动态的哲理性反思。反观《阿凡达:水之道》,对于视觉奇观的过度倚重大大压缩了艺术想象和叙事创意的空间,更迭的数字技术仅仅沦为电影商业体系中精心打造的概念和符号,混乱且自相矛盾的叙事建构致使电影走向了真实感的反面。数字技术的发展孕育出新的叙事艺术及其建构方式,强调叙事与技术二者的良性互动才能促进科幻类影片叙事的革新,实现影片“聚焦现实,积极揭示未来潜在的可能性”的深层次价值追求。