Atzera

Gianni Pagnini

Group Leader. Ikerbasque Research Associate

T +34 946 567 842
F +34 946 567 842
E gpagnini@bcamath.org

Information of interest

My scientific interests concern in a wide sense both turbulent dispersion and anomalous diffusion. 

For what concerns turbulent mixing, my research activities are devoted to the Lagrangian features of turbulence with applications to environmental problems and turbulent premixed combustion, as well as to fundamental issues. In particular they are focused on the modelling of the absolute and the relative dispersion by means of nonlinear stochastic differential equations and on turbulent reacting flows by including the level-set method.

For what concerns anomalous diffusion, my research activities are driven in the framework of Fractional Calculus and focused on the so-called fractional diffusion. In particular they require tools and methods belonging to the integral transform theories and to the field of the so-called Special Functions and involve L�vy stable densities.

  • Pre-asymptotic analysis of Lévy flights 

    Pagnini, G.Autoridad BCAM; Araújo, H. (2024)
    We study the properties of Lévy flights with index 0 < α < 2 at elapsed times smaller than those required for reaching the diffusive limit and we focus on the bulk of the walkers’ distribution rather than on its tails. ...
  • The tempered space-fractional Cattaneo equation 

    Beghin, L.; Garra, R.; Mainardi, F.; Pagnini, G.Autoridad BCAM (2023)
    We consider the time-fractional Cattaneo equation involving the tempered Caputo space-fractional derivative. There is an increasing interest in the recent literature for the applications of the fractional-type Cattaneo ...
  • The tempered space-fractional Cattaneo equation 

    Beghin, L.; Garra, R.; Mainardi, F.; Pagnini, G.Autoridad BCAM (2022)
    We consider the time-fractional Cattaneo equation involving the tempered Caputo space-fractional derivative. There is an increasing interest in the recent literature for the applications of the fractional-type Cattaneo ...
  • A generalized Stefan model accounting for system memory and non-locality 

    Garra, R.; Falcini, F.; Voller, V.R.; Pagnini, G.Autoridad BCAM (2020-05)
    The Stefan problem, involving the tracking of an evolving phase-change front, is the prototypical example of a moving boundary problem. In basic one- dimensional problems it is well known that the front advances as the ...
  • Gaussian processes in complex media: new vistas on anomalous diffusion 

    Di Tullio, F.; Paradisi, P.Autoridad BCAM; Spigler, R.; Pagnini, G.Autoridad BCAM (2019-09)
    Normal or Brownian diffusion is historically identified by the linear growth in time of the variance and by a Gaussian shape of the displacement distribution. Processes departing from the at least one of the above conditions ...
  • Finite-energy Lévy-type motion through heterogeneous ensemble of Brownian particles 

    Sliusarenko, O.Autoridad BCAM; Vitali, S.Autoridad BCAM; Sposini, V.; Paradisi, P.Autoridad BCAM; Chechkin, A.V.; Castellani, G.; Pagnini, G.Autoridad BCAM (2019-02-01)
    Complex systems are known to display anomalous diffusion, whose signature is a space/time scaling $x \sim t^\delta$ with $\delta \neq 1/2$ in the probability density function (PDF). Anomalous diffusion can emerge jointly ...
  • Restoring property of the Michelson-Sivashinsky equation 

    Trucchia, A.; Pagnini, G.Autoridad BCAM (2019)
    In this paper we propose a derivation of the Michelson-Sivashinsky (MS) equation that is based on front propagation only, in opposition to the classical derivation based also on the flow field. Hence, the characteristics ...
  • Fractional kinetics in random/complex media 

    Pagnini, G.Autoridad BCAM (2019)
    In this chapter, we consider a randomly-scaled Gaussian process and discuss a number of applications to model fractional diffusion. Actually, this approach can be understood as a Gaussian diffusion in a medium characterized ...
  • Langevin equation in complex media and anomalous diffusion 

    Vitali, S.Autoridad BCAM; Sposini, V.; Sliusarenko, O.Autoridad BCAM; Paradisi, P.Autoridad BCAM; Castellani, G.; Pagnini, G.Autoridad BCAM (2018-07-30)
    The problem of biological motion is a very intriguing and topical issue. Many efforts are being focused on the development of novel modelling approaches for the description of anomalous diffusion in biological systems, such ...
  • The role of the environment in front propagation 

    Trucchia, A.; Pagnini, G.Autoridad BCAM (2018-07-09)
    In this work we study the role of a complex environment in the propagation of a front with curvature-dependent speed. The motion of the front is split into a drifting part and a fluctuating part. The drifting part is ...
  • Effective self-similar expansion for the Gross-Pitaevskii equation 

    Modugno, M.; Pagnini, G.Autoridad BCAM; Valle-Basagoiti, M.A. (2018-04)
    We consider an effective scaling approach for the free expansion of a one-dimensional quantum wave packet, consisting in a self-similar evolution to be satisfied on average, i.e., by integrating over the coordinates. A ...
  • Wildfire propagation modelling 

    Pagnini, G.Autoridad BCAM; Egorova, V.; Trucchia, A.; Mentrelli, A.Autoridad BCAM; Kaur, I. (2018)
    Wildfires are a concrete problem with a strong impact on human life, property and the environment, because they cause disruption and are an important source of pollutants. Climate change and ...
  • Wildland fire propagation modelling 

    Egorova, V.; Pagnini, G.Autoridad BCAM; Trucchia, A. (2017-12)
    Wildfire propagation modelling is a challenging problem due to its complex multi-scale multi-physics nature. This process can be described by a reaction- diffusion equation based on the energy balance principle. Alternative ...
  • Front Curvature Evolution and Hydrodynamics Instabilities 

    Pagnini, G.Autoridad BCAM; Trucchia, A. (2017-06-07)
    It is known that hydrodynamic instabilities in turbulent premixed combustion are described by the Michelson-Sivashinsky (MS) equation. A model of the flame front propagation based on the G-equation and on stochastic ...
  • Darrieus-Landau instabilities in the framework of the G-equation 

    Pagnini, G.Autoridad BCAM; Trucchia, A. (2017-04)
    We consider a model formulation of the flame front propagation in turbulent premixed combustion based on stochastic fluctuations imposed to the mean flame position. In particular, the mean flame motion is described by ...
  • Turbulence and fire-spotting effects into wild-land fire simulators 

    Kaur, I.; Mentrelli, A.Autoridad BCAM; Bosseur, F.; Filippi, J.-B.; Pagnini, G.Autoridad BCAM (2016-01-01)
    This paper presents a mathematical approach to model the effects and the role of phenomena with random nature such as turbulence and fire-spotting into the existing wildfire simulators. The formulation proposes that the ...
  • Fractional kinetics emerging from ergodicity breaking in random media 

    Molina-Garcia, D.; Minh Pham, T.; Paradisi, P.Autoridad BCAM; Manzo, C.; Pagnini, G.Autoridad BCAM (2016)
    We present a modelling approach for diffusion in a complex medium characterized by a random lengthscale. The resulting stochastic process shows subdiffusion with a behavior in qualitative agreement with single particle ...
  • Modelling wildland fire propagation by tracking random fronts 

    Pagnini, G.Autoridad BCAM; Mentrelli, A.Autoridad BCAM (2014-12-31)
    Abstract. Wildland fire propagation is studied in the liter- ature by two alternative approaches, namely the reaction– diffusion equation and the level-set method. These two ap- proaches are considered alternatives to each ...
  • Short note on the emergence of fractional kinetics 

    Pagnini, G.Autoridad BCAM (2014-12-31)
    In the present Short Note an idea is proposed to explain the emergence and the observation of processes in complex media that are driven by fractional non-Markovian master equations. Particle trajectories are assumed to ...
  • Fractional relaxation with time-varying coefficient 

    Garra, R.; Giusti, A.; Mainardi, F.; Pagnini, G.Autoridad BCAM (2014-12-31)
    From the point of view of the general theory of the hyper-Bessel operators, we consider a particular operator that is suitable to generalize the standard process of relaxation by taking into account both memory effects of ...

Informazio gehiago

Date Title Place
2013-02-26 BCAM Workshop Environmental Mathematics Day BCAM - Basque Center for Applied Mathematics, Bilbao, Basque Country - Spain
2013-01-22
The randomized level-set method for tracking front in turbulent flows
Department of Mathematics, University of Bologna, Italy