Study on the effect of inflow direction on the hydrodynamic characteristics of underwater manipulators

Abstract

When operating in water, an underwater manipulator is subjected to different directions of flows. Thus, its hydrodynamic performance and flow-field evolution vary. Herein, the hydrodynamic coefficients and flow field characteristics of an underwater manipulator with different incoming flow directions in a subcritical range are studied. The effects of the different inflow directions on the hydrodynamic coefficients and the flow field evolution of the sectional shape, spacing, and arrangement order are numerically investigated. Results indicate that the hydrodynamic coefficients of the upstream circular section decrease at γ = 60° as the angle of the inflow direction increases. The root-mean-square value of the lift coefficient of the downstream elliptical section increases by a factor 1.5 with an increase in the inflow angle. When the elliptical section is upstream, the working attitude of the underwater manipulator is relatively stable. The research conclusions of this work will provide help for the precise positioning and fishing of underwater manipulators in the ocean.