Abstract

The Apollo Command Module had a tendency to flip over upon impact with the ocean surface after returning from space (9/19 times). In an effort to better characterize the inversion process for future water landing vehicles, experimental results for a simplified buoyant cylindrical puck impacting the water surface are presented. This study focuses on the dependence of inversion upon vertical velocity, horizontal velocity, and the pitch angle of the puck relative to the free surface. High-speed images reveal an asymmetric cavity that forms upon water impact. The asymmetric cavity then collapses, applying a moment, which can be sufficient to invert the puck after impact. Increasing the vertical velocity increases the likelihood of inversion. The puck never flipped over below a vertical velocity of 3.75 m/s. Increasing the horizontal velocity also slightly increases the likelihood of inversion. However, the largest effect of increasing horizontal velocity is to shift the range of impact angles for which the puck will invert to lower angles. The buoyant cylindrical puck used in this study requires a higher Froude number (4.34) to invert than previous geometries which have been studied.

Degree

College and Department

Ira A. Fulton College of Engineering and Technology; Mechanical Engineering

Rights

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