Verification and validation of RANS maneuvering simulation of Esso Osaka: effects of drift and rudder angle on forces and moments
The present work covers rigorous verification and validation of a Reynolds averaged Navier-Stokes (RANS) code applied to a maneuvering problem covering the "static rudder" and "pure drift" conditions. The objectives are: (1) to apply the RANS technology together with the Chimera grid technique to compute the hydrodynamic forces acting on the bare hull and the appended hull of the tanker Esso Osaka during simple maneuvers; (2) to provide detailed information about the levels of verification and validation for the integral quantities; (3) to develop a procedure for generation of the systematically refined Chimera grids, which are used for the verification; and (4) to provide information about the trends in the forces and moments when the rudder and drift angles are varied. The flow problem is solved by the general-purpose RANS code CFDSHIP-IOWA, which is run in steady mode. The effect of the free surface is neglected and the two-equation k-omega model, models the turbulence. The verification and validation are performed by means of one of the latest approaches. It takes both the numerical and experimental uncertainties and errors into account, when the method is validated. The verification and validation of the forces and moments show that fair levels of verification and validation are established for most of the considered cases. A brief summary of the levels validation says that the bare hull results are validated at levels from 4.2% to 9.3%. For the appended hull the levels of validation for the rudder forces and the overall forces and moments range from 3.4% to 28.0% and from 6.3% to 37.2% for the "static rudder" and "pure drift" conditions, respectively. Further, it appears that even though validation is not achieved for all the cases, the method is generally capable of capturing the overall behavior of the integral quantities when the rudder and drift angles are varied. (C) 2003 Elsevier Science Ltd. All rights reserved.
verification and validation rans maneuvering chimera grid rudder-hull interaction