Lucia Parussini

• University of Trieste

This paper presents the uncertainty quantification and sensitivity analysis of the standard k-ɛ turbulence model applied to the numerical prediction of the non-cavitating and cavitating flow around a 2D NACA66MOD hydrofoil. The turbulence model parameters are treated as epistemic uncertain variables, and the forward propagation of uncertainty is ev...

This paper presents the results of an Uncertainty Quantification and Sensitivity Analysis carried out for the − SST turbulence model applied to the bi-dimensional study of Vortex Induced Vibrations of an elastically mounted cylinder. The turbulence model parameters are treated as epistemic uncertain variables and the forward propagation of uncertai...

This paper illustrates how multi-fidelity metamodels can be efficiently applied to save time and costs in parametric design optimization, which normally requires simulating numerically a large number of designs. Datasets of high fidelity (HF) and middle-low fidelity (LF) simulations, obtained for instance from computational models solved by grid di...

In recent years, digital models, and in particular Digital Twins (DTs), have seen a growing interest due to their ability to provide support in the development of more efficient systems and processes. This study presents the preliminary steps taken to develop a DT model for a marine Large Bore Dual-Fuel engine manufactured by Wärtsilä. The correlat...

This paper presents the Global Sensitivity Analysis of the coefficients of the standard k- ε turbulence model used in RANS (Reynolds Averaged Navier-Stokes) simulations aimed to predict the flow around a bi-dimensional hydrofoil operating at non-cavitating and cavitating flow regimes. The sensitivity analysis is treated by the Sobol Decomposition,...

The article presents the solution adopted in an existing blast furnace with only two safety valves to minimize the dust and gas emissions to the atmosphere, in case of emergency relief due to abnormal overpressure during operating issues in the blast furnace process. Before the implementation of the system, several openings of the emergency bleeder...

View Video Presentation: https://doi.org/10.2514/6.2022-0506.vid In this paper, we propose the use of the composite kernel function (CKL) technique for the multi-fidelity Kriging (MFK) surrogate model. The principle of MFK-CKL is to automatically learn the best combination of single kernels in both low- and high-fidelity Kriging to create a more ac...

Uncertainty-based optimisation techniques provide optimal airfoil designs that are less vulnerable to the presence of uncertainty in the operational conditions (i.e., Mach number, angle-of-attack, etc.) at which an airfoil is functioning. These uncertainty-based techniques typically require numerous function evaluations to accurately calculate the...

This paper presents the multi-objective optimisation of the MH114 high-lift airfoil. We seek the set of Pareto optimal solutions that maximise the airfoil lift and minimise the drag. The lift and drag forces are considered uncertain due to geometrical uncertainties. The uncertainty quantification of the probabilistic aerodynamic force values requir...

In this work, a design optimisation strategy is presented for expensive and uncertain single- and multi-objective problems. Computationally expensive design fitness evaluations prohibit the application of standard optimisation techniques and the direct calculation of risk measures. Therefore, a surrogate-assisted optimisation framework is presented...

The purpose of this study is to simulate the distribution of a coarse granular material discharged in a hopper via a conveyor belt. This simulation is intended to be a model calibration for an optimization that will be later performed to obtain a proper material distribution device. From the hopper, the material is discharged in a blast furnace. He...

The Non-Intrusive Polynomial Chaos method is employed to analyze incompressible and laminar fluid flows in presence of geometric uncertainties on the boundaries, which are described by stochastic variables with known probability distribution. Non-Intrusive methods allow the use of existing deterministic solvers, which are treated as black boxes. Th...

In order to analyze incompressible and laminar fluid flows in presence of geometric uncertainties on the boundaries, the Non-Intrusive Polynomial Chaos method is employed, which allows the use of a deterministic fluid dynamic solver. The quantification of the fluid flow uncertainties is based on a set of deterministic response evaluations, which ar...

In order to perform the accurate tuning of a machine and improve its performance to the requested tasks, the knowledge of the reciprocal influence among the system's parameters is of paramount importance to achieve the sought result with minimum effort and time. Numerical simulations are an invaluable tool to carry out the system optimization, but...

A fictitious domain approach for the solution of second-order linear differential problems is proposed; spectral/hp elements have been used for the discretization of the domain. The peculiarity of our approach is that the Lagrange multipliers are particular distributed functions, instead of classical (Formula presented.) Dirac (impulsive) multiplie...

Purpose – This paper aims to deal with an efficient strategy for robust optimization when a large number of uncertainties are taken into account. Design/methodology/approach – ANOVA analysis is used in order to perform a variance-based decomposition and to reduce stochastic dimension based on an appropriate criterion. A massive use of metamodels a...

The paper investigates the sensitivity of numerically computed flow fields to uncertainties in thermodynamic models for complex organic fluids. Precisely, the focus is on the propagation of uncertainties introduced by some popular thermodynamic models to the numerical results of a computational fluid dynamics solver for flows of molecularly complex...

In this paper the Tensorial-expanded Chaos Collocation method has been used to solve Fluid Dynamic problems with geometric uncertainties. The main advantage of the Tensorial-expanded Chaos Collocation method is its non-intrusive formulation, so existing deterministic solvers can be used. A Least-Squares Spectral Element Method has been employed for...

A tensorial-expanded chaos collocation method is developed to take into account uncertainties on thermodynamic properties of complex organic substances. Precisely, we analyse the effect of uncertainties introduced by several thermodynamic models on the numerical results provided by a computational fluid dynamics solver for flows of molecularly comp...

We consider the application of Fictitious Domain approach combined with least squares spectral elements for the numerical solution of fluid dynamic incompressible equations. Fictitious Domain methods allow problems formulated on a complicated shaped domain Ω to be solved on a simpler domain Π containing Ω. Least Squares Spectral Element Method has...

In this paper the Tensorial-expanded Chaos Collocation method has been applied to fluid dynamic problems with geometric tolerances and aleatoric boundary conditions. The main advantage of the Tensorial-expanded Chaos Collocation method is its non-intrusive formulation, so existing deterministic solvers can be used. A Least-Squares Spectral Element...

We consider the application of Fictitious Domain approach combined with Least Squares Spectral Elements for the numerical solution of partial differential equations. Fictitious Domain methods allow problems formulated on a complicated shaped domain Ω to be solved on a simpler domain Π containing Ω. Least Squares Spectral Element Method has been use...

In this work a multi objective Robust Design of a transonic airfoil has been performed. For uncertainty quantification of the stochastic process different non-intrusive methodologies have been compared in order to find the more suitable for our purposes. The main advantage of non-intrusive formulation is that existing deterministic solvers can be u...

Robust Design Optimization (RDO) using traditional approaches such as Monte Carlo (MC) sampling requires tremendous computational expense. Performing a RDO for problems involving time consuming CAE analysis may not even be possible within time constraints. In this paper a new stochastic modeling technique based on chaos collocation method is used t...

Different polynomial chaos methods coupled to the fictitious domain approach have been applied to one- and two-dimensional elliptic problems with multi uncertain variables in order to compare the accuracy and convergence of the methodologies. Both intrusive and non-intrusive methods have been considered, with particular attention to their employmen...

In this paper the Non-Intrusive Polynomial Chaos Method coupled to a Fictitious Domain approach has been applied to one- and twodimensional elliptic problems with geometric uncertainties, in order to demonstrate the accuracy and convergence of the methodology. The main advantage of non-intrusive formulation is that existing deterministic solvers ca...

We propose a fictitious domain method combined with spectral/hp elements for the solution of second-order differential problems. This paper presents the formulation, validation and application of fictitiuos domain-spectral/hp element algorithm to one- and two-dimensional Poisson problems. Fictitious domain methods allow problems formulated on an in...

In this paper we illustrate a new method for design of wings based on the optimization of the performance stability. This technique is an alternative approach to the traditional one which considers just a design point and tends to ``over-optimize'', producing solutions that perform well at the design point but have poor off-design characteristics....