Large Flow Separations around a Generic Submarine in Static Drift Motion Resolved by Various Turbulence Closure Models

Abstract

A thorough numerical introspection for assessing the particular issues of large flow separations around a submersible hull by using various turbulence models is described. The generic Defense Advanced Research Projects Agency (DARPA hereafter) Suboff hull is considered in the present study. Detailed descriptions of the mathematics behind the hybrid Shear Stress Transport (SST), Detached Eddy Simulation (DES) and the Improved Delayed Detached Eddy Simulation (IDDES) are given. The ISIS solver of the FineTM/Marine package is used to solve the flow problems. An adaptive mesh refinement is employed for resolving the flow inside the areas hosting significant flow gradients. Two sets of computations are analyzed: one refers to the straight-ahead course, whereas the other is focused on the static drift motions. Four angles of incident flow and three different incoming flow velocities are proposed for clarifying the details of the flow separation. Extensive grid convergence tests are performed for both working regimes and for all the meshes used in the present investigation. Extended verification and validation (V&V hereafter) of the numerical approach is performed through extensive comparisons with the experimental data. Global hydrodynamic performance of the hull as well as the local flow features are discussed in detail. The study is concluded by a series of final remarks aimed at providing useful information for further similar investigations.

A Simplified Method of Iceberg Hydrodynamic Parameter Prediction

“…To close the set of Equations ( 5) and ( 6), the model of the shear stress transfer (MSST) [20] is used, well proven when applied to typical near-wall flows, including those with flow separation [21][22][23]. This is a generalization of two well-known turbulence models in the practice of engineering calculations: k − model [24] and low Reynolds k − ω Suffman-Wilcox model [25] (involved in the near-wall region).…”

Assessment of Numerical Captive Model Tests for Underwater Vehicles: The DARPA SUB-OFF Test Case

“…Thus, DES (detached eddy simulation) methods have recently emerged. Lungu [15,16] reported on a thorough investigation of the flow around a submarine model under straight-ahead and static drift conditions, using a range of turbulence models to assess the unique issues of large-scale flow separation involved. Wang et al [17,18] discovered that the presence of the hull and the interaction with the free surface substantially impacted the propeller performance in a series of computational studies for underwater geometries operating close to the free surface.…”