Ubaldo CellaUniversity of Rome Tor Vergata | UNIROMA2
Ubaldo Cella
PhD
About
64
Publications
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Introduction
Ubaldo Cella currently works at University of Rome Tor Vergata. Ubaldo does research in Aerospace Engineering. Their current project is 'RBF4AERO (www.rbf4aero.eu)'.
Additional affiliations
August 1996 - July 1998
Publications
Publications (64)
Numerical optimization procedures are one of the most powerful approaches with which to support design processes. Their implementation, nevertheless, involves several conceptual and practical complexities. One of the key points relates to the geometric parameterization technique to be adopted and its coupling with the numerical solver. This paper d...
Numerical simulations to evaluate thoracic aortic hemodynamics include a computational fluid dynamic (CFD) approach or fluid-structure interaction (FSI) approach. While CFD neglects the arterial deformation along the cardiac cycle by applying a rigid wall simplification, on the other side the FSI simulation requires a lot of assumptions for the mat...
Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High fidelity simulations are obtained using the fine spatial resolution of both the structural and fluid computational g...
The fluid dynamic design of hydrofoils involves most of the typical difficulties of aeronautical wings design with additional complexities related to the design of a device operating in a multiphase environment. For this reason, “high fidelity” analysis solvers should be, in general, adopted also in the preliminary design phase. In the case of mode...
The present paper addresses the numerical fluid-structure interaction (FSI) analysis of a thermowell immersed in a water flow. The study was carried out implementing a modal superposition approach into a computational fluid dynamics (CFD) solver. The core of the procedure consists in embedding the structural natural modes, computed by a finite elem...
A procedure for the optimization of a catamaran’s sail plan able to provide a preliminary optimal appendages configuration is described. The method integrates a sail parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The sa...
Retractable hydrofoils may enhance performances of seaplane during take-off and landing runs by lowering the speed when the hull is leaving or touching water surface. Hydrofoils are designed to complement airlift with additional hydrodynamic lift elevating the hull above the water at a speed lower than take-off speed; this minimizes slamming phenom...
Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High fidelity simulations are obtained using the fine spatial resolution of both the structural and fluid computational g...
Several experimental databases of aeroelastic measurements performed on aircraft wing models are available for the validation of
fluid–structure interaction (FSI) numerical methodologies. Most of these databases are used to model scaled systems focusing primarily on aerodynamic aspects, rather than on structural similitude with a full-scale model....
In this thesis an FSI approach based on modes superposition is proposed and implemented in order to numerically capture the lock-in condition of a thermowell immersed in a water flow. The transient analysis has been conducted computing the natural modes with ANSYS Mechanical and embedding them into ANSYS Fluent through the mesh morphing Add-On RBF...
Retractable hydrofoils may enhance performances of seaplane during take-off and landing runs by lowering the speed when the hull is leaving or touching water surface. Hydrofoils are designed to complement airlift with additional hydrodynamic lift elevating the hull above the water at a speed lower than take-off speed; this minimizes slamming phenom...
Numerical simulations to evaluate thoracic aortic hemodynamics include a computational fluid dynamic (CFD) approach or fluid-structure interaction (FSI) approach. While CFD neglects the arterial deformation along the cardiac cycle by applying a rigid wall simplification, on the other side the FSI simulation requires a lot of assumptions for the mat...
Radial basis functions (RBFs) based mesh morphing allows to adapt the shape of a computational grid onto a new one by updating the position of all its nodes. Usually nodes on surfaces are used as sources to define the interpolation field that is propagated into the volume mesh by the RBF. The method comes with two distinctive advantages that makes...
High fidelity Fluid-Structure Interaction (FSI) can be tackled by means of non-linear Finite Element Models (FEM) suitable to capture large deflections of structural parts interacting with fluids and by means of detailed Computational Fluid Dynamics (CFD). High fidelity is gained thanks to the spatial resolution of the computational grids and a key...
The public RIBES database available at http://ribes-project.eu/experiments/ is herein attached, including the pdf version of the web page with full details about published data.
The RIBES project "Radial basis functions at fluid Interface Boundaries to Envelope flow results for advanced Structural analysis", coordinated by the University of Rome "...
High fidelity calculation tools are well established in the nautical design sector where advanced numerical simulations are adopted for the prediction of the interaction of boat parts with surrounding fluids. The capability to couple such tools with efficient shape parametrization procedures offers the possibility to further improve the performance...
This book discusses the recent advances in aircraft design methodologies. It provides an overview of topics such as shape optimization, robust design and aeroelasticity, focusing on fluid-structure numerical methodologies to address static and dynamic aeroelastic problems. It demonstrates that the capability to evaluate the interaction between aero...
Heart valve diseases are among the leading causes of cardiac failure around the globe. Current advances in imaging technology, in numerical simulation and in additive manufacturing are opening new frontiers in the field of development of new personalised prosthetic devices. The 3D printing technique could allow the realisation of personalised model...
Heart valve diseases are among the leading causes of cardiac failure around the globe. Current advances in imaging technology, in numerical simulation and in additive manufacturing are opening new frontiers in the field of development of new personalised prosthetic devices. The 3D printing technique could allow the realisation of personalised model...
The design of sailing boats appendages requires taking in consideration a large amount of design variables and diverse sailing conditions. The operative conditions of dagger boards depend on the equilibrium of the forces and moments acting on the system. This equilibrium has to be considered when designing modern fast foiling catamarans, where the...
The capability to reduce the structural weight of aircrafts, and consequently the fuel consumption, is related to the accuracy of numerical tools and to the efficiency of design methodologies available. In particular, the capability to model the interaction of the several mechanisms involved in physics phenomena represents a key point in the develo...
Purpose
This paper aims to present a fast and effective approach to tackle complex fluid structure interaction problems that are relevant for the aeronautical design.
Design/methodology/approach
High fidelity computer-aided engineering models (computational fluid dynamics [CFD] and computational structural mechanics) are coupled by embedding mod...
In the mechanical engineering world, there is a growing interest in being able to create so-called “digital twins” to assess the impact to performance or response. Part of the challenge is to be able to include and assess manufactured geometries as opposed to nominal design intent, particularly for components that are sensitive to small shape varia...
Computational Fluid Dynamics (CFD), as early used in the design stage, helps engineers to come up with the optimum design of a sail in a reasonable timeframe. However, traditional CFD tools are approximate and need to be validated when it comes to predicting the dynamic behaviour of non-developable shape with high camber and massively detached flow...
A common issue in Multiphysics analysis regards a reliable way for loose couplings, because the same object is modelled using different mesh refinements, each one suited for a proper field of physics. Output data originating in a simulation environment are transferred as input data to a different model to run a new analysis. It is strongly desirabl...
Mesh morphing is one of the most promising approach for problems in which numerical analyses, based on discretised domains, involve shape parameterization. Some of the benefits associated to its adoption are the reduction of the computational meshing costs and the remeshing noise prevention, guaranteeing at the same time the continuum shape paramet...
A geometric tool for a catamarans sail plan and appendages optimization procedure is descripted. The method integrates a parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The boat performance is obtained, in an iterative p...
The present document details the aeroelastic measurements campaign performed on the wind tunnel model developed within the RIBES project. The content was extracted from the final test report provided by the University of Naples “Federico II” who was in charge to perform the experimental campaign. A selection of the most significant tests are report...
Purpose
The present paper aims to address the description of a numerical optimization procedure, based on mesh morphing, and its application for the improvement of the aerodynamic performance of an industrial glider which suffers of a large separation occurring in the wing–fuselage junction region at high incidence angles.
Design/methodology/appro...
A numerical static aeroelastic analysis procedure, applying a modal approach in coupling the fluid dynamic and structural solutions, is presented. The method is based on a preliminary structural modal analysis from which a number of natural modes is selected to be used in the creation of a fluid dynamic domain morphing criterion. The mesh is made p...
An optimisation procedure for catamarans sail plan and appendages is descripted. The method integrates a parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The sailing speed and course angle are obtained, with an iterative...
This paper demonstrates a way of solving industrial aerodynamic shape optimization problems using the RBF4AERO platform, developed in the framework of the EU–funded RBF4AERO project. The platform combines optimization algorithms (stochastic and gradient– based ones), a mesh morphing tool based on Radial Basis Functions (RBFs) and various evaluation...
This paper presents the RBF4AERO benchmark technology platform, developed in the framework of the EU-funded RBF4AERO project. The platform enables the so-called Benchmark Management System (BMS) used for benchmark submission and results reporting. The BMS is deployed using three modules, namely the Graphical User Interface (GUI), the Work-flow Mana...
This paper demonstrates the solution of industrial aerodynamic shape optimization problems using the optimization methods provided by the RBF4AERO platform, developed in the framework of the EU–funded RBF4AERO project (Grant Agreement No: 605396). The platform provides a complete infrastructure needed for optimization problems, including GUI, Optim...
Presentation of the talk had during the EASN 5th International Workshop on Aerostructure held on 4th September 2015 in Manchester (UK).
Purpose – The present paper aims to address the description of a numerical optimization procedure, based on mesh morphing, and its application for the improvement of the aerodynamic performance of an industrial glider which suffers of a large separation occurring in the wing–fuselage junction region at high incidence angles.
Design/methodology/app...
An aerodynamic numerical optimisation procedure for an AC72 rigid wing sail was developed. The core of the methods is the geometric parameterisation strategy based on mesh morphing technique. The morphing action, which uses radial basis functions, is integrated within the Reynolds-averaged Navier-Stokes solver and provides an efficient parametric s...
The present paper is addressed to the improvement of the aerodynamic design of an industrial glider flying at Mach 0.08. The original design exhibits performance affecting separation occurring in the wing-fuselage junction region at high incidence angles. Adopting a numerical optimization approach affordable in the case that HPC resources are limit...
La tecnica di mesh morphing RBF è il fulcro del progetto RBF4AERO, che ha come scopo quello di sviluppare
la RBF4AERO Benchmark Technology, ovvero una piattaforma numerica integrata e delle metodologie per fronteggiare efficientemente le più complesse sfide della progettazione e ottimizzazione di velivoli.
A procedure coupling Reynold-averaged Navier-Stokes computation and finite element method analysis based on the use of radial basis functions has been set up and validated against experimental data. A static fluid-structure simulation on a complete aircraft configuration has been performed coupling high-fidelity methods. The analysis was performed...
Within the European Project Telfona the Pathfinder Model was designed, analyzed
numerically, constructed and tested with the aim of obtaining a laminar flow testing
capability in the European Transonic Wind Tunnel (ETW). The model was designed for
natural laminar flow (NLF) for transonic flow conditions with high Reynolds number.
Results of pre-tes...
A transonic natural-laminar-flow wing design procedure has been set up, integrating a parametric geometry model with several analysis tools. A direct design strategy has been applied and three levels of aerodynamic analysis have been used: a full-potential method (with which to rapidly iterate to obtain the target pressure distribution), an Euler s...
Within the European Project Telfona the Pathfinder Model was designed, analyzed numerically, constructed and tested with the aim to obtain the capability of laminar flow testing of the European Transonic Wind Tunnel (ETW). The model was
designed for natural laminar flow (NLF) for transonic flow conditions with high Reynolds number. Pre-test numeric...
The design of a new transonic Natural Laminar Flow wing has been carried out recently at CIRA with the collaboration of Piaggio Aeroindustries S.p.A., in the framework of the research project “VITAS” founded by the Italian government. The new wing has two design points at M=0.75 C L=0.5 and M=0.78 C L= 0.46, both at Re=8·10 6 (based on the mean aer...
Navier-Stokes Multiblock code solves the fully coupled system of equations simultaneously using a cell-centered finite-volume approach. This note assesses the sensitivity to some turbulence models and numerical schemes implemented in Navier-Stokes Multiblock when computing two test cases in standard mode, i.e., without tuning the code to these two...