A Numerical Study of the Descent and Ascent Motion of a Full Ocean Depth Human Occupied Vehicle

Abstract

To meet the needs of scientific discoveries in hadal zones, the hadal science and technology center (HAST) of Shanghai Ocean University has made a significant commitment to construct a movable laboratory for hadal trenches in 2013, which includes a mothership, an full ocean depth (FOD) human occupied vehicle (HOV), an FOD Autonomous and Remotely-operated Vehicle (ARV) and several FOD landers. Presently, the HOV is in concept design phase. Current HOVs in service could only work below 7,000m. To increase the submergence depth from 7,000m to 11,000m for a FOD HOV, the time spending in descent and accent will take a majority part of power endurance and leave little time in scientific studies. Hence, the descent/ascent motion analysis and optimization will play a bigger role in FOD HOV designs contrasting to current HOVs. In this paper, in order to investigate resistance characteristics and drag coefficients in decent and ascent directions of the FOD HOV, the Reynolds Averaged Navier-Stokes (RANS) equations were solved using computational fluid dynamics. To achieve a faster descent and ascent process, diving and floating with various attacking angles were tried. The numerical analysis for each scenario has been conducted and results were discussed. The method and theory presented in the paper will be applied to the design of a practical deep manned submersible.