Application of non-linear k-e turbulence model in flow simulation over underwater axisymmetric hull at higher angle of attack

Abstract

This paper addresses the Computational Fluid Dynamics Approach (CFD) to simulate the flow over underwater axisymmetric bodies at higher angle of attacks. Three Dimensional (3D) flow simulation is carried out over MAYA Autonomous Underwater Vehicle (AUV) at a Reynolds number (Re) of 2.09×106. These 3D flows are complex due to cross flow interaction with hull which produces nonlinearity in the flow. Cross flow interaction between pressure side and suction side is studied in the presence of angle of attack. For the present study standard k-ε model, non-linear k-ε model models of turbulence are used for solving the Reynolds Averaged Navier-Stokes Equation (RANS). The non-linear k-ε turbulence model is validated against DARPA Suboff axisymmetric hull and its applicability for flow simulation over underwater axisymmetric hull is examined. The non-linear k-ε model performs well in 3D complex turbulent flows with flow separation and flow reattachment. The effect of angle of attack over flow structure, force coefficients and wall related flow variables are discussed in detail. Keywords: Computational Fluid Dynamics (CFD); Autonomous Underwater Vehicle (AUV); Reynolds averaged Navier-Stokes Equation (RANS); non-linear k-ε turbulence modeldoi: http://dx.doi.org/10.3329/jname.v8i2.6984 Journal of Naval Architecture and Marine Engineering 8(2011) 149-163

Numerical simulations of flow past an autonomous underwater vehicle at various drift angles

“…Though the appended vehicle is not axisymmetric, starboard-port symmetry exists. Sakthivel et al, (2011), which was determined after a detailed validation and domain independence study for the barehull. The details of the various domain sizes and the corresponding drag coefficients are provided in Table 2.…”

“…The implementation of this UDF was earlier validated for flow past a square cylinder (Ramesh et al, 2006) and flow past a circular cylinder (Ayyappan and Vengadesan, 2008). In addition, the implementation of this UDF for underwater vehicles was validated by Sakthivel et al, (2011) by studying flow past a barehull at different drift angles of the vehicle.…”

“…Barros et al (2008 a, b) studied the flow past an axisymmetric barehull at different incidence angles using standard models for turbulence closure. Recently, Sakthivel et al (2011) applied a non-linear k-ε model to study flow characteristics and variation of flow variables, forces at different incidence angles for a Myring type, axisymmetric barehull. Details of flow simulations for fully appended AUV at different incidence angles using RANSE based CFD are rather scarce.…”

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

“…Plenty of authors have published their papers in dealing with the determination of forces and moments (Vaz et al, 2010), the influence by using different turbulence closure models (Phillips et al, 2010;Sakthivel et al, 2011), the verification and validation of the results (Simonsen et al, 2003;Zhang, 2010), the comparison of dynamic characteristics of different geometries and configurations , and even the real simulation coupled with motions via overlapping grid techniques (Carrica et al, 2012) as well as the optimization process (Rajabi and Kavianpour, 2014). As recently reviewed by Stern et al (2013) and Stern et al (2014), CFD capabilities continue to advance at even faster speed, and are changing the face of shipbuilding industry by transforming the build-and-test design spiral approach to the simulation-based design (SBD) approach.…”

Unsteady CFD simulation of 3D AUV hull at different angles of attack

“…2(a). The entire study is conducted considering two different computational domains around the AUV hull (Shaktivel et al, 2011). Initially, the zero angle of attack case is solved using a smaller base domain (5.77Lx0.625L x0.625L) and structured H-type grid is used in this domain as shown in Fig.…”