This paper focuses on the Verification and Validation procedure (V&V) applied in the particular case of rowing boats with both steady and unsteady surge motions. The different approaches proposed in literature are applied and compared to better estimate the a posteriori error. In order to compare numerical results with towing tank experimental data and exactly make validation of the code ICARE3D, the basin geometry (width = 5 m, depth = 3 m) is taken into account. The validation procedure is applied with a set of six grids. For unsteady simulations, unsteady resistant coefficient is compared to experiments in terms of time histories and Fourier components.
INTRODUCTION A rowing boat is a dynamic physical system. The rowers and their oars transfer momentum to the boat, causing an unsteady forward speed. The process is complicated by the motion of the rowers within the boat itself, introducing coupled pitch and heave motions too. Many forms of drag are manifest in resisting the motion of the boat such as skin, form, wave and aero-dynamical. This paper focuses specifically on hydrodynamic drag, which is viscous dominated in the case of rowing boats (viscous drag is about 90% of the total resistance). What makes the problem both fascinating and challenging from an engineering and computer modelling perspective is the pulsatory form of propulsion (see Fig.1). However, accounting for dynamic effects has generally been far removed from the actual design process due to the complexity of simulating unsteady flows. Even if the goal of total six degree of freedom predicted motions should be kept in mind, a detailed investigation of the results obtained with one degree of freedom is the first step in establishing confidence in unsteady Reynolds averaged Navier-Stokes (RANS) simulations. The present work presents a completely thorough analysis, including verification and validation and using the unsteady RANS code ICARE3D (B. Alessandrini and G. Delhommeau, 1997), continually adapted and enhanced to meet the requirements of new and more complicated simulations.