The analysis of the interference effects on an high-speed catamarans is carried out by means of the numerical solution of the Reynolds Averaged Navier-Stokes equations. Focus is on the analysis of the viscous effects on the interference, and its dependency on the Reynolds number. To this aim, numerical simulations were carried out for Re ranging from ~10^6 to ~10^8, for two different values of the Froude number (Fr=0.30, 0.45). The analysis is carried out by means of an in house parallel unsteady RANS solver, based on a finite volume discretization. The free surface is handled by means of a suitable single phase level set algorithm; moreover, Chimera overlapping grid capabilities have been implemented. Wave patterns, wave profiles, surface pressure and velocity fields are analyzed and comparison is made with the demihull configuration. Dependencies of the pressure and viscous resistance coefficients, as well as of the interference factor on the Reynolds number, is investigated. Verification and validation of the computed resistance coefficients is also performed. Copyright © 2009 by The International Society of Offshore and Polar Engineers (ISOPE).
Analysis of the hydrodynamic performances of high-speed catamarans by viscous flow solver
Broglia R;Zaghi S;Di Mascio;
2009
Abstract
The analysis of the interference effects on an high-speed catamarans is carried out by means of the numerical solution of the Reynolds Averaged Navier-Stokes equations. Focus is on the analysis of the viscous effects on the interference, and its dependency on the Reynolds number. To this aim, numerical simulations were carried out for Re ranging from ~10^6 to ~10^8, for two different values of the Froude number (Fr=0.30, 0.45). The analysis is carried out by means of an in house parallel unsteady RANS solver, based on a finite volume discretization. The free surface is handled by means of a suitable single phase level set algorithm; moreover, Chimera overlapping grid capabilities have been implemented. Wave patterns, wave profiles, surface pressure and velocity fields are analyzed and comparison is made with the demihull configuration. Dependencies of the pressure and viscous resistance coefficients, as well as of the interference factor on the Reynolds number, is investigated. Verification and validation of the computed resistance coefficients is also performed. Copyright © 2009 by The International Society of Offshore and Polar Engineers (ISOPE).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
