Development of hybrid URANS–LES methods for flow simulation in the ship stern area

Abstract The paper presents the results of the application of a new hybrid URANS–LES method for the investigations of the ship wake behind the tanker KVLCC2. The switching between URANS and LES models is based on the ratio between the turbulence scale and the cell size of the mesh. Ship resistance, fields of the axial velocity and turbulent kinetic energy in the propeller plane are calculated and compared with measurements. Much attention is paid to the analysis of the unsteady velocities, their PDF distributions and spectra. Numerical analysis shows that the instantaneous velocities deviate substantially from their mean values which are usually used as the estimated velocities in modern engineering methodologies. The thrust variation in the unsteady wake is more than twice as large as that in the time averaged (frozen) wake. The results of the present study point out that the unsteadiness in the wake behind full ships can be very large and should be taken into account when propulsion and unsteady loadings are determined.

[1]  L. Temmerman,et al.  A hybrid two-layer URANS–LES approach for large eddy simulation at high Reynolds numbers , 2005 .

[2]  Florian R. Menter,et al.  TURBULENCE MODELS BASED ON THE LENGTH-SCALE EQUATION , 2005 .

[3]  K. Abe,et al.  AN INVESTIGATION OF HYBRID LES/RANS MODELS FOR PREDICTING FLOW FIELDS WITH SEPARATION , 2005, Proceeding of Fourth International Symposium on Turbulence and Shear Flow Phenomena.

[4]  P. Durbin.  Near-wall turbulence closure modeling without “damping functions” , 1991, Theoretical and Computational Fluid Dynamics.

[5]  P. Spalart.  Detached-Eddy Simulation , 2009 .

[6]  Heinz Pitsch,et al.  Consistent boundary conditions for integrated LES/RANS simulations: LES outflow conditions , 2002 .

[7]  Rickard Bensow,et al.  Current Capabilities of DES and LES for Submarines at Straight Course , 2010 .

[8]  Shia Hui Peng.  HYBRID RANS-LES MODELING BASED ON ZERO- AND ONE-EQUATION MODELS FOR TURBULENT FLOW SIMULATION , 2005 .

[9]  H. Schlichting.  Boundary Layer Theory , 1955 .

[10]  P. Spalart.  Comments on the feasibility of LES for wings, and on a hybrid RANS/LES approach , 1997 .

[11]  H. Werner,et al.  Large-Eddy Simulation of Turbulent Flow Over and Around a Cube in a Plate Channel , 1993 .

[12]  Shin Hyung Rhee,et al.  Assessment of eight turbulence models for a three-dimensional boundary layer involving crossflow and streamwise vortices , 2002 .

[13]  Lars Davidson,et al.  Hybrid LES-RANS: An approach to make LES applicable at high Reynolds number , 2005 .

[14]  D. H. Kim,et al.  Measurement of flows around modern commercial ship models , 2001 .

[15]  Suak-Ho Van,et al.  Wind tunnel tests on flow characteristics of the KRISO 3,600 TEU containership and 300K VLCC double-deck ship models , 2003 .

[16]  Lars Davidson,et al.  Hybrid LES-RANS using synthesized turbulent fluctuations for forcing in the interface region , 2006 .