A Numerical study on the hydrodynamic performance of an immersed foil: Uncertainty quantification of RANS and SPH methods

Abstract

The hydrodynamic characteristics of floating or immersed bodies may be evaluated by a variety of numerical techniques. Although these currently available techniques are well-established for providing valuable information about the flow, recently emerging techniques like Smoothed-Particle-Hydrodynamics (SPH) have also proven to provide promising results. Verification and validation are important steps in assessing the fidelity of the techniques; enabling the quantification of the uncertainty associated with them. In this research effort, the wave-making characteristics and the hydrodynamic performance of an immersed hydrofoil in open channel conditions have been investigated by state-of-the-art numerical techniques. A commercially available RANS package and an in-house Smoothed-Particle-Hydrodynamics code have been utilized. Experimental results on the induced wave profile and wave resistance have been compared with numerical results. The flow has been observed to show highly unsteady nature; which has been captured by both methods. Uncertainty of both numerical tools associated with wave amplitude have been quantified. The uncertainty of the RANS package has also been quantified for wave resistance. Both techniques have been validated in terms of the investigated hydrodynamic parameters. Hydrodynamic performance of the foil, i.e. variation of lift and drag with Froude number has also been assessed by both methods; enabling the revelation of current limitations and prospective potential of the adopted SPH approach.