Scientific Publications and CFD Research

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DrATC+: A Divide et Impera Extension to Trust-Based Dynamic Routing

Davide Ferraris, Letizia Russo, Lorenzo Monti

2025

CUBIT S.c.ar.l., University of Malaga

Abstract

Authors: Davide Ferraris, Letizia Russo, Lorenzo Monti

Keywords: Trust, Network, Routing, IoT, Security

Trust is a critical yet often overlooked factor in network routing, especially in decentralized and dynamic environments such as IoT and ad-hoc networks. The DrATC algorithm addressed this gap by incorporating a comprehensive set of trust characteristics into dynamic routing decisions. In this paper, we propose DrATC+, an extension of the original model that applies the divide et impera (divide and conquer) principle to trust-based routing. DrATC+ enhances resilience and security by splitting messages into segments and routing them through multiple trusted paths, selected based on composite trust evaluations. We present the design and operational workflow of the algorithm, supported by evaluation scenarios. Our results demonstrate that DrATC+ can improve fault tolerance and mitigate the impact of malicious nodes adapting effectively to changing trust conditions. This work lays the foundation for more robust and adaptive trust-aware routing protocols in future networked systems.

Conference/Journal: Security and Trust Management (STM 2025), Lecture Notes in Computer Science, vol 16137, Springer

DOI: https://doi.org/10.1007/978-3-032-06155-3_7

Status: Published

Springer

Enhancing diffuser performance using transverse grooves to delay flow separation

Alessandro Mariotti, Amedeo Cesare Giovanni Bertini, Gianmarco Lunghi, Giovanni Lombardi, Marco Maganzi, Maurizio Boffadossi, Simone Fenili

2024

Cubit, Ferrari, Politecnico di Milano, Università di Pisa

Abstract

Authors: Alessandro Mariotti, Amedeo Cesare Giovanni Bertini, Gianmarco Lunghi, Giovanni Lombardi, Marco Maganzi, Maurizio Boffadossi, Simone Fenili

Keywords: CFD, Computational fluid dynamics, Aerodynamics, Flow control, Boundary layer flow, Turbulent flows

A flow-control method is applied to enhance the efficiency and flow homogeneity of three-dimensional diffusers used in open-jet wind tunnels. Suitably shaped grooves are introduced in the diffuser diverging walls. The grooves promote the relaxation of the non-slip condition along the streamlines bounding the small recirculation regions forming passively inside the grooves. That reduces momentum losses and results in a downstream boundary layer with higher momentum, which is more separation-resistant.

In this study, circular and square-section diffusers with different degrees of flow separation were examined. The grooves significantly enhanced performance in circular diffusers by reducing the extent of separation and promoting an axisymmetric and spatially uniform flow. However, negligible benefits were observed for square-section diffusers. In these cases, since flow separation originates from one of the four inclined edges of the diffuser, placing grooves along the diverging walls does not effectively reduce the separation extent. Nonetheless, the grooves become effective again in diffusers with rectangular cross sections of high aspect ratio.

Conference/Journal: Physics of Fluids 36(10), 105164 (October 2024)

DOI: https://pubs.aip.org/aip/pof/article-abstract/36/10/105164

Status: Published

Physics of Fluids

DrATC: Dynamic routing Algorithm based on Trust Characteristics

2024

Cubit Innovation Labs, University of Malaga

Abstract

Authors: Davide Ferraris, Lorenzo Monti

Keywords: Trust, Network, Routing, IoT, Security, Dynamic Routing, BGP, OSPF

In this paper, we propose a dynamic routing algorithm that leverages various trust characteristics to determine the most trusted path in a network. Trust, a multifaceted concept, encompasses attributes such as direct and indirect experiences, transitivity, directionality, context-dependence, and more.

Our approach allows the routing protocol to selectively incorporate these characteristics to enhance the decision-making process. For instance, in scenarios prioritizing direct trust, nodes route packets based solely on direct interactions with their neighbors. In more complex scenarios, both direct and indirect trust are considered, utilizing recommendations from trusted nodes to establish trust with previously un-contacted nodes.

We also explore the use of alternative routes based on specific trust values, ensuring sensitive data is routed through the most trustworthy paths. By integrating these trust metrics, the proposed algorithm dynamically adapts to varying network conditions and requirements, improving the overall reliability and security of the data transmission.

Our experimental results demonstrate the algorithm's effectiveness in selecting trusted paths and highlight the importance of context and adaptability in trust-based routing. This work contributes to the field by providing a flexible and robust framework for incorporating trust into dynamic routing decisions, paving the way for more secure and reliable network communication.

Conference/Journal: The 20th International Workshop on Security and Trust Management (STM 2024)

Status: In press

STM 2024

An Innovative Optimization Procedure for Supercavitating Foils

Catherine Ramirez, Giovanni Lombardi, Michele Farnesi, Romain Lanos

2021

Cubit, Syroco, Università di Pisa

Abstract

The Syroco Lab research and simulation team, under the leadership of Ph.D Catherine Ramirez Villalba and Ph.D Romain Lanos, is leveraging modeFRONTIER for automating simulation processes and optimizing the design of several critical components of the Syroco speedcraft. One of the most challenging aspects is to optimize the profile of the foil that anchors the speedcraft to water, and needs to work in both subcavitating and supercavitating regimes.

The major challenge in this high-performance foil design is the requirement for a hydrodynamics optimization procedure to obtain the desired performance and stability, while taking into account the feasibility of the components and controlling the computational costs. While hydrodynamic characteristics were evaluated using CFD software, the feasibility of the wing construction was evaluated with a Finite Elements Method analysis imposing custom forces from CFD results.

This procedure led to a well-defined and fast design space exploration obtaining a wing drag reduction of more than 25% with respect to a reference solution with an imposed target lift. The simulation and optimization process evaluated 4,063 designs, singling out 594 designs complying with constraints.

Journal: International CAE Conference and Exhibition, November 2021

DOI/Source: https://engineering.esteco.com/blog/modefrontier-design-fastest-speedcraft/

Keywords: Supercavitation, CFD optimization, Syroco, World Sailing Speed Record, modeFRONTIER

International CAE Conference, Vicenza (IT)

Optimization of Sandblasting Gun

Emanuele Grasso, Giovanni Lombardi, Marco Maganzi

2021

CUBIT S.c.ar.l., NORBLAST S.r.l., University of Pisa

Abstract

Authors: Emanuele Grasso, Giovanni Lombardi, Marco Maganzi

Keywords: CFD, optimization, sandblasting, DEM, modeFRONTIER, StarCCM+

The use of CFD and optimization cycles is becoming fundamental for saving time and reducing design costs in industrial applications where fluid dynamics plays a critical role. This work presents a CFD-based optimization methodology for sandblasting gun geometry, aimed at maximizing output velocity and media supply rate.

The optimization strategy employed a two-phase approach. First, a preliminary validation of the numerical method was performed against experimental tests on the reference configuration, achieving satisfying agreement. The optimization cycle was then executed considering only the air flow, with the best configurations subsequently verified through Discrete Element Method (DEM) simulations including material injection.

The gun geometry was parameterized using 21 design variables. The optimization workflow integrated modeFRONTIER as the optimization platform, Matlab for workflow management, CATIA V5 for parametric CAD modeling, and StarCCM+ for CFD simulations. The dual objectives were to maximize both the output velocity and the mass flow rate of the media supply tube.

The optimization process explored 4,364 geometric configurations, of which 1,421 were valid and 1,274 showed improvement over the reference design. The three best configurations—optimized for highest output velocity, highest sand supply, and best compromise between both parameters—were validated through complete DEM simulations, confirming the effectiveness of the optimization approach.

Conference/Journal: International CAE Conference 2021

Status: Published

CAE Conference 2021

Active Aerodynamics to Increase the Features of a Motorcycle

Giovanni Lombardi, Marco Maganzi, Pasqualetto Elena

2020

Cubit, Università di Pisa

Abstract

ADAMo (Adaptive Digital Aerodynamics for Motorcycles) is a research project guided by Piaggio S.p.A and partially funded by the Toscana region. The objective was to increase the performance, safety and comfort of a motorcycle by using active aerodynamics devices.

The paper describes the aerodynamics development, which was essentially based on intensive CFD use (STAR CCM+ code), related to the choice of the active devices and their optimization. Grids with about 100 million cells were used for preliminary evaluations and final verifications; for analysis of aerodynamic devices and optimization, grids with about 40 million cells were used.

There is an increase in lateral force and in both roll and yawing moments, resulting in a gain in lateral stability. There is also a significant decrease in turbulence. The mean turbulence value decreased by about 30% compared to the reference configuration, while the maximum value decreased more than 40% (in the zone of the driver legs). CFD results were verified in a wind tunnel, with differences less than 5% on the global values.

Journal: Proceedings of 20. Internationales Stuttgarter Symposium, Springer Vieweg

DOI/Source: https://link.springer.com/chapter/10.1007/978-3-658-29943-9_14

Keywords: CFD, Motorcycle aerodynamics, Active devices, ADAMo, Piaggio

Springer Verlag ISBN 978-3-658-29942-2

Sailboat Keel Optimization

Giovanni Lombardi, Marco Maganzi

2020

CUBIT S.c.ar.l., University of Pisa

Abstract

Authors: Giovanni Lombardi, Marco Maganzi

Keywords: CFD, optimization, sailboat, keel, hydrodynamics, modeFRONTIER

High-level sport serves as a powerful driver for research, particularly in the fields of aerodynamics and hydrodynamics. This work presents a multi-level optimization methodology for sailboat keels, aimed at reducing hydrodynamic drag during racing conditions.

The optimization strategy consists of two complementary phases. In the first phase, a two-dimensional optimization defines the optimal fin section profile using Bezier curves parameterized with 8 design variables. This process employs modeFRONTIER as the optimization platform, Matlab for workflow management, and X-Foil for aerodynamic analysis. In the second phase, a three-dimensional optimization determines the complete fin-bulb system geometry through 21 design parameters with a constraint on bulb volume. Three-dimensional CFD simulations were performed using StarCCM+ on an HPC cluster with 1024 cores, while parametric CAD modeling was carried out in CATIA V5.

The objective function balances performance across different sailing points: F_obj = 0.4·Cd_downwind + 0.6·Cd_upwind, assigning greater weight to upwind conditions, which are typically more critical for overall racing performance.

Conference/Journal: International CAE Conference 2020

Status: Published

CAE Conference 2020

Comparison of two Multiphase Procedures on a Commercial Vehicle in Rain Conditions

Antonio Ercoli, Giacomo De Angeli, Giovanni Lombardi, Marco Maganzi

2019

Cubit, Maserati, Università di Pisa

Abstract

In automotive design, the study of the water thin layer over a car due to rain is becoming increasingly important: the challenge is to obtain a way to describe the behavior of the water over a vehicle in rainy conditions and its interactions with wipers and drainage systems, to determine potential failures of the vehicle design.

In this paper two similar numeric procedures have been realized with the software STAR CCM+ to analyze the dynamic of water thin layer starting from the impingement of the rain on the car surface and taking into account even the motion of the wipers over the windshield. Moreover, the water that flows through the drainage systems is monitored to figure out if the water could produce a malfunction of components near them.

In order to describe each status of the water, many multiphase models are used. These methodologies have been applied on a commercial vehicle model and the results have been examined and compared to each other. The analysis shows a better description of the reality for one of them, leading to the possibility of using it as a design tool in the automotive industry.

Journal: International Journal of Automotive Technology, Vol. 20, pp. 1123-1129 (2019)

DOI/Source: https://doi.org/10.1007/s12239-019-0105-9

Keywords: Multiphase, CFD, Rain Conditions, Overset, Morphing, Automotive

International Journal of Automotive Technology, vol. 20, pp. 1123 – 1129

The pre processing priority in fluid dynamics design

Antonio Ercoli, Giovanni Lombardi, Marco Maganzi

2019

Cubit, Università di Pisa

Abstract

Authors: Antonio Ercoli, Giovanni Lombardi, Marco Maganzi

Keywords: CFD, preprocessing, mesh quality, simulation accuracy, fluid dynamics

In computational fluid dynamics, the quality of results is fundamentally determined by the preprocessing phase. This paper examines the critical role of mesh generation, boundary condition setup, and geometry preparation in achieving accurate CFD simulations. Through systematic analysis of various preprocessing approaches applied to automotive and industrial cases, we demonstrate how preprocessing decisions directly impact solution convergence, accuracy, and computational efficiency. Best practices for mesh refinement strategies, near-wall treatment, and geometry simplification are presented based on extensive validation against experimental data.

Conference/Journal: 8th Before Reality Conference, Münich (DE)

8th Before Reality Conference, Münich (DE)

Aerodynamic design and preliminary optimization of a commercial PrandtlPlane aircraft

Karim Abu Salem, Marco Carini, Marco Maganzi, Michael Méheut, Stylianos Kanellopulos, Vincenzo Binante, Vittorio Cipolla

2019

Cubit, Università di Pisa

Abstract

The paper presents the phases and achievements of aerodynamic design activities carried out on a box-wing aircraft called PrandtlPlane, proposed as a sustainable solution for meeting the demanding requirements of fast-growing air transport. The activities are included in the PARSIFAL project ("Prandtlplane ARchitecture for the Sustainable Improvement of Future AirpLanes"), funded by the European Union under the Horizon2020 Program.

Starting from the conceptual aerodynamic design of the PrandtlPlane architecture, the paper follows the development of the aerodynamic design, dealing with the preliminary definition of a reference configuration, whose performances have been evaluated with both low and high fidelity tools, and the optimization procedure for the improvement of cruise performance.

The PrandtlPlane is a box-wing aircraft based on Prandtl's studies on multiplane lifting systems. A box-wing designed according to the Prandtl "best wing system" minimizes the induced drag for given lift and span, and thus has the potential to reduce fuel consumption and noxious emissions.

Journal: EUCASS 2019 (European Conference for Aeronautics and Space Sciences), Madrid

DOI/Source: https://hal.science/hal-02904449

Keywords: Box-wing, PrandtlPlane, PARSIFAL, CFD, Aerodynamic optimization

8th European Conference for Aeronautics and Space Sciences (EUCASS), Madrid (ES)

Publications

DrATC+: A Divide et Impera Extension to Trust-Based Dynamic Routing

Abstract

Enhancing diffuser performance using transverse grooves to delay flow separation

Abstract

DrATC: Dynamic routing Algorithm based on Trust Characteristics

Abstract

An Innovative Optimization Procedure for Supercavitating Foils

Abstract

Optimization of Sandblasting Gun

Abstract

Active Aerodynamics to Increase the Features of a Motorcycle

Abstract

Sailboat Keel Optimization

Abstract

Comparison of two Multiphase Procedures on a Commercial Vehicle in Rain Conditions

Abstract

The pre processing priority in fluid dynamics design

Abstract

Aerodynamic design and preliminary optimization of a commercial PrandtlPlane aircraft

Abstract

• Cubit joins the Toradex Partner Network for embedded systems and IoT solutions

• Cubit among Intesa Sanpaolo’s Imprese Vincenti 2026

• New scientific publication: DrATC – Trust-based routing algorithm

• Cubit joins Texas Instruments’ partner ecosystem