Viscous-flow Calculations of Submarine Maneuvering Hydrodynamic Coefficients and Flow Field based on Same Grid Topology

Abstract

To estimate the maneuverability of a submarine at the early design stage, an accurate evaluation of the hydrodynamic coefficients is important. In a collaborative exercise, the authors performed calculations on the bare hull DRAPA SUBOFF submarine to investigate the capability of viscous-flow solvers to predict the forces and moments as well as flow field around the body. A typical simulation program was performed for both the steady drift tests and rotating arm tests. The same grid topology based on multi-block mesh strategy was used to discretize the computational domain. A procedure designated drift sweep was implemented to automatically increment the drift angle during the simulation of steady drift tests. The rotating coordinate system was adopted to perform the simulation of rotating arm tests. The Coriolis force and centrifugal force due to the computation in a rotating frame of reference were treated explicitly and added to momentum equations as source terms. Lastly, the computed forces and moment as a function of angles of drift in both conditions are compared with experimental results and literature values. They always show the correct trend. Flow field quantities including pressure coefficients and vorticity and axial velocity contours are also visualized to vividly describe the evolution of flow motions along the hull.

A numerical investigation about the effects of Reynolds number on the flow around an appended axisymmetric body of revolution

“…Numerous computational studies on the towed DSub configuration are available in the literature, where usually the Reynolds-averaged Navier-Stokes (RANS) equations are solved due to cost considerations (Gorski, Coleman & Haussling 1990;Givler et al 1991;Boger & Dreyer 2006;Toxopeus 2008;Pan, Zhang & Zhou 2012;Budak & Beji 2016;Cao, Zhu & Zeng 2016;Manshadi, Hejranfar & Farajollahi 2017;Gao et al 2018;Wang et al 2018;Zhang, Chao & Pan 2019), with some works dealing also with the free-surface effects (Shariati & Mousavizadegan 2017;Amiri et al 2018). More recently, hybrid formulations such as the detached eddy simulation (DES) approach are gradually replacing RANS in the design cycle.…”