Mancini, Simone (2015) The problem of verification and validation processes of CFD simulations of planing hulls. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Resource language: English
Title: The problem of verification and validation processes of CFD simulations of planing hulls
Date: 31 March 2015
Number of Pages: 125
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Industriale
Scuola di dottorato: Ingegneria industriale
Dottorato: Ingegneria aerospaziale, navale e della qualità
Ciclo di dottorato: 28
Coordinatore del Corso di dottorato:
De Luca,
Date: 31 March 2015
Number of Pages: 125
Keywords: CFD; planing craft simulation; verification & validation; overset grid; URANS simulations; ship hydrodynamics
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/01 - Architettura navale
Date Deposited: 11 Apr 2016 09:29
Last Modified: 31 Oct 2016 10:48

Collection description

In the context of Computational Fluid Dynamic (CFD) application in ship hydrodynamic field it is well known that the numerical simulations of planing crafts are significantly less reliable rather displacement hulls. For this reason it is important to perform a comprehensive approach to the verification and validation (V&V) methodologies and procedures in order to obtain high-quality results of CFD simulations of planing hulls. In the first stage of this work, an assessment of the accuracy and effectiveness of different simulations setups and techniques for planing craft is performed, paying particular attention to the different techniques of moving mesh, such as the single moving grid, overset/chimera grid, and morphing mesh, and to the problems related to the air-water interface models, such as the numerical ventilation of the hull bottom. In the second stage the results of the V&V study for four different hull models are reported at four Froude numbers (Fr). The Unsteady Reynolds Average Navier Stokes (URANS) code results are validated using benchmark experimental data obtained for three warped hulls, characterized by systematic variation of the slenderness ratio (L/B) and for one monohedral hull with comparable L/B. Grid independence, iteration, time-step, and statistical convergence analysis for response variables (resistance coefficients, wetted surfaces, and dynamic trim angles) are performed using the main uncertainty estimation methods available in the literature. The same procedures are repeated for the wave profiles analysis. The results of this work show that is possible to improve the reliability of the numerical simulation of the planing craft reducing the errors and uncertainties related to the predictions of resistance, running attitude and wave pattern. It should be note that the error has a significant hull geometry dependency. Moreover the results of the V&V study highlight that the sources of errors investigated have different importance on the numerical error and uncertainty and the modelling of the physics of the planing craft is a critical point to improve the reliability of the numerical simulation.


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