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Papers by Renata Archetti

Research paper thumbnail of Radial gravity currents in vertically graded porous media: Theory and experiments for Newtonian and power-law fluids

This study theoretically and experimentally explores the behaviour of axisymmetric gravity curren... more This study theoretically and experimentally explores the behaviour of axisymmetric gravity currents of Newtonian and power-law fluids in inhomogeneous porous media. Systematic heterogeneity along the vertical is represented by a power-law permeability variation governed by the parameter x, mimicking trends in natural media. A self-similar solution describing (i) the rate of propagation and (ii) the profile of the current is derived by considering a current of volume proportional to time raised to a non-negative power a. Four critical values of a are determined: the first two affect the time dependency of the radius, height and average gradient of the current on flow behaviour index n and x; the third one dictates if the current accelerates or decelerates; the fourth one governs the asymptotic validity of the thin current approximation. Experimental validation is performed using shear-thinning suspensions and Newtonian mixtures in constant-and variable-flux regimes. A stratified porous medium composed of four uniform strata of glass beads with different diameters is used for this purpose. The experimental results for the radius and profile of the current agree well with the self-similar solution except at the beginning of the process, due to the limitations of the 1-D assumption and to boundary effects near the injection zone. An uncertainty analysis indicates that the rheological fluid behaviour and the variation in permeability significantly affect the propagation of the current.

Research paper thumbnail of Longo et al Supplementary material JFM-13-RP-0554 2013

Research paper thumbnail of Longo et al Video 2 test 12 date 28 02 2013 bis JFM 2013

Research paper thumbnail of video 1 Axisymmetric gc shear thickening

Research paper thumbnail of Winter sandy protections of the northern Adriatic Coast against flooding: preliminary results

Journal of Coastal …, 2009

... the performance of the different protection's systems, to perform some numerical... more ... the performance of the different protection's systems, to perform some numerical modelling, by using ... of the wave data used for the simulation: H (top), Dir (centre) and T (bottom) ... characteristics such as storm duration and wave period modulate the morphodynamic response due ...

Research paper thumbnail of Experimental Investigations of Wave Propagation over the Swash Zone

Ocean Wave Measurement and Analysis (2001), 2002

Research paper thumbnail of Roundhead Stability of Berm Breakwaters

Coastal Engineering 1996, 1997

Research paper thumbnail of Towards improving the representation of beaching in oil spill models: A case study.

Oil–shoreline interaction (or “beaching” as commonly referred to in literature) is an issue of ma... more Oil–shoreline interaction (or “beaching” as commonly referred to in literature) is an issue of major concern in oil spill modeling, due to the significant environmental, social and economic importance of coastal areas. The present work studies the improvement of the representation of beaching brought by the introduction of the Oil Holding Capacity approach to estimate oil concentration on coast, along with new approaches for coast type assignment to shoreline segments and the calculation of permanent oil attachment to the coast. The above were tested for the Lebanon oil spill of 2006, using a modified version of the open-source oil spill model MEDSLIK-II. The modified model results were found to be in good agreement with field observations for the specific case study, and their comparison with the original model results denote the significant improvement in the fate of beached oil brought by the proposed changes.

Research paper thumbnail of Berm breakwaters stone degradation

Research paper thumbnail of Armor Stone Abrasion due to Displacements in Sea Storms

Journal of Waterway Port Coastal and Ocean Engineering-asce, 2003

A model to estimate volume loss of armor stones caused by abrasion under wave conditions occurrin... more A model to estimate volume loss of armor stones caused by abrasion under wave conditions occurring during a structure's lifetime is proposed. It accounts only for abrasion caused by stone movements, neglecting the effects of stone breakage, wetting-drying, freezing-thawing cycles, and chemical attack and is based on the assumption of proportionality between abraded volume and abrasion work. The model represents rock resistance to abrasion and to unit size and makes use of empirical relationships providing the average frequency of movement and displacement length of armor units. Wave loading is described with a probabilistic analysis. The present model is discussed in the light of a previous one. The comparison makes possible the estimation of the influence of external agents, other than stone mobility and size, on volume loss.

Research paper thumbnail of The PRIMI Project: August-September 2009 validation cruise on oil spill detection and fate

Research paper thumbnail of State-of-the-Art of Designing and Constructing Berm Breakwaters

Research paper thumbnail of The PRIMI Project: August-September 2009 validation cruise on oil spill detection and fate

Research paper thumbnail of Contribution of Cosmo/SkyMed data into PRIMI: A pilot project on marine oil pollution. results after one year of operations

In this paper we present the Pilot Project PRIMI, designed to provide information on marine oil s... more In this paper we present the Pilot Project PRIMI, designed to provide information on marine oil spills, and its validation campaign, held in august 2009, conducted with the oceanography ship Urania. During the experiment CosmoSkymed has provided an extraordinary contribution supplying almost any day images over the area inspected by the ship and in some cases also images requested with short notice.

Research paper thumbnail of Radial gravity currents in vertically graded porous media: theory and experiments for Newtonian and power-law fluids

This study theoretically and experimentally explores the behaviour of axisymmetric gravity curren... more This study theoretically and experimentally explores the behaviour of axisymmetric gravity currents of Newtonian and power-law fluids in inhomogeneous porous media. Systematic heterogeneity along the vertical is represented by a power-law permeability variation governed by the parameter omega\omegaomega, mimicking trends in natural media. A self-similar solution describing (i) the rate of propagation and (ii) the profile of the current is derived by considering a current of volume proportional to time raised to a non-negative power alpha\alphaalpha. Four critical values of alpha\alphaalpha are determined: the first two affect the time dependency of the radius, height and average gradient of the current on flow behaviour index nnn and omega\omegaomega; the third one dictates if the current accelerates or decelerates; the fourth one governs the asymptotic validity of the thin current approximation.
Experimental validation is performed using shear-thinning suspensions and Newtonian mixtures in constant- and variable-flux regimes. A stratified porous medium composed of four uniform strata of glass beads with different diameters is used for this purpose. The experimental results for the radius and profile of the current agree well with the self-similar solution except at the beginning of the process, due to the limitations of the 1-D assumption and to boundary effects near the injection zone. An uncertainty analysis indicates that the rheological fluid behaviour and the variation in permeability significantly affect the propagation of the current.

Research paper thumbnail of Effect of variable permeability on the propagation of thin gravity currents in porous media

A new formulation is proposed to study the influence of deterministic heterogeneity on the propag... more A new formulation is proposed to study the influence of deterministic heterogeneity on the propagation of thin two-dimensional gravity currents in a porous medium above a horizontal impervious boundary. Heterogeneity is conceptualized as a monotonic power-law variation of medium permeability transverse or parallel to the direction of propagation. Considering the injection of a constant or time-variable volume of fluid, the nonlinear differential problem admits a similarity solution which describes the shape and rate of propagation of the current. The bounds on parameters necessary to respect model assumptions are derived asymptotically and for finite time, to clarify the range of applicability of the proposed models. An application to the migration of a contaminant gravity current in the subsurface is then discussed, showing the impact of permeability variations on extension and shape of the intrusion.

Research paper thumbnail of INTEGRATED BEACH MANAGEMENT AT IGEA MARINA, ITALY: RESULTS OF TEN-YEARS MONITORING

Proceedings of the …, 2011

This contribution analyses the hydro-morphological effects induced by low crested structures conf... more This contribution analyses the hydro-morphological effects induced by low crested structures confined by lateral groynes at Igea Marina beach, Northern Adriatic Sea, Italy The site has been monitored since the works started for these last ten years. Results from bathymetric surveys, sediment samplings, video monitoring and numerical modelling are presented and discussed.

Research paper thumbnail of Towards validating a last generation, integrated wave-current-sediment numerical model in coastal regions using video measurements

This paper presents the first steps in the implementation of a morphological numerical model to b... more This paper presents the first steps in the implementation of a morphological numerical model to be applied in the Bevano River region, a shallow water area in the Adriatic Sea, with the aim of helping the identification and assessment of erosional patterns and bottom morphological modifications induced by severe marine storms. The numerical modeling, performed using a fully 3D coupled wave-current-sediment version of the ROMS model, has been complemented with in situ data analysis and observations: a first qualitative validation of the results was given by the analysis of images acquired via an ARGUS video station.

Research paper thumbnail of Quantifying the Evolution of a Beach Protected by Low Crested Structures Using Video Monitoring

... a low frequency loses a great deal of important information, such as the seasonal variability... more ... a low frequency loses a great deal of important information, such as the seasonal variability ofmorphodynamic behaviour ... Vertical lines in the bottom panel are the nourishment events ... Theevolution of total MIP can also be considered as significant to describe the evolution of the ...

Research paper thumbnail of Long trend shoreline evolution of a beach protected by structures

... a great deal of important information, such as the seasonal variability of morphodynamic beha... more ... a great deal of important information, such as the seasonal variability of morphodynamic behaviour. ... Vertical lines in bottom panel are the nourishment events and rearrangement of the ... org Zanuttigh B.(2007)-Numerical modelling of the morphological response induced by low ...

Research paper thumbnail of Radial gravity currents in vertically graded porous media: Theory and experiments for Newtonian and power-law fluids

This study theoretically and experimentally explores the behaviour of axisymmetric gravity curren... more This study theoretically and experimentally explores the behaviour of axisymmetric gravity currents of Newtonian and power-law fluids in inhomogeneous porous media. Systematic heterogeneity along the vertical is represented by a power-law permeability variation governed by the parameter x, mimicking trends in natural media. A self-similar solution describing (i) the rate of propagation and (ii) the profile of the current is derived by considering a current of volume proportional to time raised to a non-negative power a. Four critical values of a are determined: the first two affect the time dependency of the radius, height and average gradient of the current on flow behaviour index n and x; the third one dictates if the current accelerates or decelerates; the fourth one governs the asymptotic validity of the thin current approximation. Experimental validation is performed using shear-thinning suspensions and Newtonian mixtures in constant-and variable-flux regimes. A stratified porous medium composed of four uniform strata of glass beads with different diameters is used for this purpose. The experimental results for the radius and profile of the current agree well with the self-similar solution except at the beginning of the process, due to the limitations of the 1-D assumption and to boundary effects near the injection zone. An uncertainty analysis indicates that the rheological fluid behaviour and the variation in permeability significantly affect the propagation of the current.

Research paper thumbnail of Longo et al Supplementary material JFM-13-RP-0554 2013

Research paper thumbnail of Longo et al Video 2 test 12 date 28 02 2013 bis JFM 2013

Research paper thumbnail of video 1 Axisymmetric gc shear thickening

Research paper thumbnail of Winter sandy protections of the northern Adriatic Coast against flooding: preliminary results

Journal of Coastal …, 2009

... the performance of the different protection's systems, to perform some numerical... more ... the performance of the different protection's systems, to perform some numerical modelling, by using ... of the wave data used for the simulation: H (top), Dir (centre) and T (bottom) ... characteristics such as storm duration and wave period modulate the morphodynamic response due ...

Research paper thumbnail of Experimental Investigations of Wave Propagation over the Swash Zone

Ocean Wave Measurement and Analysis (2001), 2002

Research paper thumbnail of Roundhead Stability of Berm Breakwaters

Coastal Engineering 1996, 1997

Research paper thumbnail of Towards improving the representation of beaching in oil spill models: A case study.

Oil–shoreline interaction (or “beaching” as commonly referred to in literature) is an issue of ma... more Oil–shoreline interaction (or “beaching” as commonly referred to in literature) is an issue of major concern in oil spill modeling, due to the significant environmental, social and economic importance of coastal areas. The present work studies the improvement of the representation of beaching brought by the introduction of the Oil Holding Capacity approach to estimate oil concentration on coast, along with new approaches for coast type assignment to shoreline segments and the calculation of permanent oil attachment to the coast. The above were tested for the Lebanon oil spill of 2006, using a modified version of the open-source oil spill model MEDSLIK-II. The modified model results were found to be in good agreement with field observations for the specific case study, and their comparison with the original model results denote the significant improvement in the fate of beached oil brought by the proposed changes.

Research paper thumbnail of Berm breakwaters stone degradation

Research paper thumbnail of Armor Stone Abrasion due to Displacements in Sea Storms

Journal of Waterway Port Coastal and Ocean Engineering-asce, 2003

A model to estimate volume loss of armor stones caused by abrasion under wave conditions occurrin... more A model to estimate volume loss of armor stones caused by abrasion under wave conditions occurring during a structure's lifetime is proposed. It accounts only for abrasion caused by stone movements, neglecting the effects of stone breakage, wetting-drying, freezing-thawing cycles, and chemical attack and is based on the assumption of proportionality between abraded volume and abrasion work. The model represents rock resistance to abrasion and to unit size and makes use of empirical relationships providing the average frequency of movement and displacement length of armor units. Wave loading is described with a probabilistic analysis. The present model is discussed in the light of a previous one. The comparison makes possible the estimation of the influence of external agents, other than stone mobility and size, on volume loss.

Research paper thumbnail of The PRIMI Project: August-September 2009 validation cruise on oil spill detection and fate

Research paper thumbnail of State-of-the-Art of Designing and Constructing Berm Breakwaters

Research paper thumbnail of The PRIMI Project: August-September 2009 validation cruise on oil spill detection and fate

Research paper thumbnail of Contribution of Cosmo/SkyMed data into PRIMI: A pilot project on marine oil pollution. results after one year of operations

In this paper we present the Pilot Project PRIMI, designed to provide information on marine oil s... more In this paper we present the Pilot Project PRIMI, designed to provide information on marine oil spills, and its validation campaign, held in august 2009, conducted with the oceanography ship Urania. During the experiment CosmoSkymed has provided an extraordinary contribution supplying almost any day images over the area inspected by the ship and in some cases also images requested with short notice.

Research paper thumbnail of Radial gravity currents in vertically graded porous media: theory and experiments for Newtonian and power-law fluids

This study theoretically and experimentally explores the behaviour of axisymmetric gravity curren... more This study theoretically and experimentally explores the behaviour of axisymmetric gravity currents of Newtonian and power-law fluids in inhomogeneous porous media. Systematic heterogeneity along the vertical is represented by a power-law permeability variation governed by the parameter omega\omegaomega, mimicking trends in natural media. A self-similar solution describing (i) the rate of propagation and (ii) the profile of the current is derived by considering a current of volume proportional to time raised to a non-negative power alpha\alphaalpha. Four critical values of alpha\alphaalpha are determined: the first two affect the time dependency of the radius, height and average gradient of the current on flow behaviour index nnn and omega\omegaomega; the third one dictates if the current accelerates or decelerates; the fourth one governs the asymptotic validity of the thin current approximation.
Experimental validation is performed using shear-thinning suspensions and Newtonian mixtures in constant- and variable-flux regimes. A stratified porous medium composed of four uniform strata of glass beads with different diameters is used for this purpose. The experimental results for the radius and profile of the current agree well with the self-similar solution except at the beginning of the process, due to the limitations of the 1-D assumption and to boundary effects near the injection zone. An uncertainty analysis indicates that the rheological fluid behaviour and the variation in permeability significantly affect the propagation of the current.

Research paper thumbnail of Effect of variable permeability on the propagation of thin gravity currents in porous media

A new formulation is proposed to study the influence of deterministic heterogeneity on the propag... more A new formulation is proposed to study the influence of deterministic heterogeneity on the propagation of thin two-dimensional gravity currents in a porous medium above a horizontal impervious boundary. Heterogeneity is conceptualized as a monotonic power-law variation of medium permeability transverse or parallel to the direction of propagation. Considering the injection of a constant or time-variable volume of fluid, the nonlinear differential problem admits a similarity solution which describes the shape and rate of propagation of the current. The bounds on parameters necessary to respect model assumptions are derived asymptotically and for finite time, to clarify the range of applicability of the proposed models. An application to the migration of a contaminant gravity current in the subsurface is then discussed, showing the impact of permeability variations on extension and shape of the intrusion.

Research paper thumbnail of INTEGRATED BEACH MANAGEMENT AT IGEA MARINA, ITALY: RESULTS OF TEN-YEARS MONITORING

Proceedings of the …, 2011

This contribution analyses the hydro-morphological effects induced by low crested structures conf... more This contribution analyses the hydro-morphological effects induced by low crested structures confined by lateral groynes at Igea Marina beach, Northern Adriatic Sea, Italy The site has been monitored since the works started for these last ten years. Results from bathymetric surveys, sediment samplings, video monitoring and numerical modelling are presented and discussed.

Research paper thumbnail of Towards validating a last generation, integrated wave-current-sediment numerical model in coastal regions using video measurements

This paper presents the first steps in the implementation of a morphological numerical model to b... more This paper presents the first steps in the implementation of a morphological numerical model to be applied in the Bevano River region, a shallow water area in the Adriatic Sea, with the aim of helping the identification and assessment of erosional patterns and bottom morphological modifications induced by severe marine storms. The numerical modeling, performed using a fully 3D coupled wave-current-sediment version of the ROMS model, has been complemented with in situ data analysis and observations: a first qualitative validation of the results was given by the analysis of images acquired via an ARGUS video station.

Research paper thumbnail of Quantifying the Evolution of a Beach Protected by Low Crested Structures Using Video Monitoring

... a low frequency loses a great deal of important information, such as the seasonal variability... more ... a low frequency loses a great deal of important information, such as the seasonal variability ofmorphodynamic behaviour ... Vertical lines in the bottom panel are the nourishment events ... Theevolution of total MIP can also be considered as significant to describe the evolution of the ...

Research paper thumbnail of Long trend shoreline evolution of a beach protected by structures

... a great deal of important information, such as the seasonal variability of morphodynamic beha... more ... a great deal of important information, such as the seasonal variability of morphodynamic behaviour. ... Vertical lines in bottom panel are the nourishment events and rearrangement of the ... org Zanuttigh B.(2007)-Numerical modelling of the morphological response induced by low ...