1) Groundwater hydrology and
hydraulics:
1a) Model reduction and uncertainty quantification;
1b) Characterization of heterogeneity, scaling, flow and
transport in porous and fractured media;
1c) Nonlinear (Forchheimer and non-Newtonian) flows;
1d) Subsurface heat transfer and geothermal devices;
1e) Seawater intrusion;
1f) Probabilistic risk assessment (PRA).
2) Environmental Fluid Mechanics and
Hydraulics:
2a) Free-surface debris and hyperconcentrated flow.
2b) Geophysical gravity and density currents in viscous
and inertial regime;
2c) Fluvial hydraulics and morphodynamics.
3) Urban hydraulics:
3a) Analysis of pipe failure data;
3b) Reliability analysis of water distribution and sewer
systems;
3c) Life Cycle Assessment (LCA);
3d) Decision Support Systems (DSS);
3e) Risk-based asset management.
1) Groundwater hydrology and
hydraulics:
1a) Model reduction and uncertainty
quantification. Stochastic differential equations describing
the behavior of complex environmental systems are analyzed,
together with techniques for their reduction (surrogate models).
For complex environmental problems under uncertainty, Global
Sensitivity analysis (GSA) is employed, via the adoption of
computationally efficient Polynomial Chaos Expansion methods.
1b) Characterization of
heterogeneity, scaling, flow and transport in porous and fractured
media. Heterogeneity in geologic porous media is investigated
via geostatistical methods. Scaling of hydraulic conductivity and
solute dispersivity si investigated within a unified multiscale
conceptual framework which views hydraulic conductivity as a random
fractal field. Several problems in stochastic groundwater
hydraulics (uniform flow, radial flow towards wells, solute
transport, conditioning with field measurements) have been examined
adopting the former theory, employing analytical and/or numerical
methods. Methods adopted for the description of flow and transport
are analytical and numerical (small perturbations, Monte Carlo
simulations and moment equations).
1c) Nonlinear (Forchheimer and
non-Newtonian) flows in porous and fractured media. Flow and
transport in porous media and fractures is examined when the
relationship between flux and pressure gradient is nonlinear,
either due to exceedance of the Darcy threshold, or due to the
non-Newtonian nature of the fluid . The research aims at a detailed
understanding of flow and transport phenomena at the pore or single
fracture scale, and at developing simplified methodologies and
representative parameters for larger scales.
1d) Subsurface heat transfer and
geothermics. The thermal efficiency of novel shapes of ground
heat exchangers (GHEs) employed in geothermal closed loops is
tested by solving the transient flow and heat transport problem
within the surrounding ground via analytical and numerical models.
The aim is to optimize the shape of the exchanger while minimizing
the thermal impact on the soil, and to evaluate the effect on
parameter uncertainty on model response.
1e) Seawater intrusion. The
influence of parameter uncertainty on seawater intrusion in coastal
phreatic or confined aquifers is investigated re-examining existing
analytical models under the viewpoint of risk analysis. Model
sensitivity to random input parameters is assessed by means of the
PCE technique, to evaluate the probability of a variety of
undesired events (e.g. well or sensitive area contamination).
Data-driven techniques relying on various statistical regressive
and auto-regressive models are employed for real cases in which
analytical models are not applicable, such as the Emila Romagna
phreatic aquifer.
1f) Probabilistic risk assessment
(PRA). After an in-depth analysis of existing literature on
risk analysis in natural systems (including methodologies such as
“fault tree” and “event tree” analysis), the aim is to develop a
integrated framework for risk evaluation, including: i) risk
analysis, with identification of risk factors and their
quantitative evaluation; ii) risk assessment; iii) risk reduction
and control, including the definition and implementation of a
decisional process and monitoring. The methods thus individuated,
essentially of a probabilistic nature, are applied to aquifers, to
support controlled exploitation of groundwater resources and
treatment of contaminated sites, of much interest nowadays in
connection with the recovery of industrial areas located within the
urban perimeter; specifically, for complex environmental problems
under uncertainty, Gobal Sensitivity analysis (GSA) is employed,
via the adoption of Polynomial Chaos Expansion methods.
2) Environmental Fluid Mechanics and
Hydraulics:
2a) Free-surface debris and
hyperconcentrated flow. Free-surface flow of non-Newtonian
fluids is studied in laminar and turbulent regime, with different
geometries and boundary conditions. The impact of different
rheological equations on integrated variables such as the flowrate
is examined. The research aims at a deeper understanding of debris
flow phenomena and mining sludges behavior.
2b) Geophysical viscous and inviscid
gravity and density currents. Several important phenomena in
industrial, geophysical and environmental applications involve the
relative flow of two fluids due to a density difference. Such
phenomena are studied in different geometries, for free-surface or
porous media flow, and for Newtonian and non-Newtonian fluids, the
latter with a variety of constitutive laws. The possible
propagation regimes (viscous or inertial) is investigated, pursuing
first an analytical approach and then a numerical solution.
Space-time development of gravity currents is investigated for
different values of rheological parameters. The experimental
validation of theories is pursued with laboratory experiments. The
influence of medium heterogeneity for gravity currents in porous
media is examined with a deterministic or stochastic approach.
2c) Fluvial hydraulics and
morphodynamics. The study deals with calibration of a 2-D
morphodynamic model of a stretch of the Po River (Italy) using
detailed measurements of the river's morphology and water-sediment
fluxes derived from an ADCP recording. Sensitivity analyses are
performed to analyze the effects of bed roughness and sediment
transport direction on the simulated flow field and morphology.
3) Urban hydraulics:
3a) Pipe break data analysis. A
statistical analysis of break/blockage events in water/drainage
networks is performed, with the aim of defining prediction
formulae.
3b) Reliability analysis of water
distribution and sewer systems. For water supply system, the
research aims at deriving innovative indices for nodal and overall
network performance. For sewer systems, the research aim is the
description of hydraulic and environmental performance of drainage
systems both in the present condition and in possible future
scenarios considering sewer system temporal decline and the
application of feasible rehabilitation techniques.
3c) Life Cycle Assessment (LCA).
The Life Cycle Energy Analysis (LCEA) methodology is applied to
water distribution networks, allowing to identify the most
convenient scenarios in terms of energy cost, materials choice,
technologies, and maintenance strategies. The final aim is to
provide a decision support system coupling the energy saving and
reduction of environmental impact viewpoints to reliability, risk
and cost dimensions. A pipe lifecycle is subdivided into three
phases: fabrication, use and life end. For each phase, the energy
cost associated to each functional unit is evaluated by means of a
novel theoretical approach, modifying earlier literature
findings.
3d) Decision Support Systems
(DSS). The research aim is to establish a rational framework
for water supply systems and sewer network rehabilitation decision
making, developing intermediate tools/products and a Decision
Support System (DSS) enabling municipal engineers to establish and
maintain effective management of their water supply and sewer
networks with a pro-active approach.
3e) Risk-based
Asset management. Sustainable asset management of
water supply systems, sanitary and drainage network will be pursued
under the triple bottom line approach of economic, social and
environmental aspects. Performance indicators to evaluate
sustainability are developed at different scales. These indicators
are evaluated via the urban methabolism model, which views the
integrated water cycle as a living organism, whose different parts
exchange mass and energy fluxes.
