Numerical Simulation of Oblique Towing Tests and Rotating Arm Tests for a Submarine Model in Same Grid Topology

Abstract

The numerical simulation of oblique towing tests (OTT) and rotating arm tests (RAT) for a submarine model was undertaken with the same grid topology. As for the OTT simulation, to improve the efficiency and accuracy of the computation, the drift sweep procedure was adopted. In contrast with the steady drift case, rotating motion for a submarine is more complex. The rotating reference frame was adopted to deal with the rotation problem. The Coriolis force and centrifugal force due to the computation in a body-fixed rotating coordinate system were treated explicitly and added to the momentum equations as source terms. The user-defined boundary conditions were coded to give the correct magnitude and direction of entrance velocity. Lastly, the computed forces and moments as a function of drift angle during the two kinds of simulations were compared with experimental results, as well as literature values. They always show the correct trend. The flow field and streamline patterns in rotating motion were depicted. It indicates that the method used in the paper is reliable and the same grid topology can be used for the simulation of two simplified maneuvers.