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Fluid mechanics of newtonian and non-newtonian fluids

Non-Newtonian gravity current in porous channel: experimental setup and comparison with theory (Author: Vittorio Di Federico)
Non-Newtonian gravity current in porous channel: experimental setup and comparison with theory (Author: Vittorio Di Federico)
Inviscid gravity current in a circular channel (Author: Vittorio Di Federico)
Modeling of flow in a variable aperture fracture (Author: Vittorio Di Federico)

Fluid mechanics has a wide range of environmental and industrial applications. The research group on fluid mechanics aims at deriving rigorous and applicable solutions to solve these problems with a variety of tools, including analytical, numerical, and experimental methods. In many problems encountered, the rheological behavior is akin to water, and the fluid is Newtonian; in other cases, the rheology is more complex, and the fluid, termed non-Newtonian, exhibits a non-linear relationship between shear rate and shear stress. Within this framework, the main categories of problems investigated are: (1) Steady, start-up and pulsatile flows of Bingham, power-law and Giesekus fluids in different geometries representing industrial and mining engineering settings. Exact or approximate analytical solutions are derived and compared with numerical ones. (2) Flow of thixotropic fluids, with a complex molecular structure, whose rheological characteristics change with time. (3) Viscous gravity currents of complex fluids in free-surface or porous flow. Closed form or numerical solutions describing the flow field are derived and compared with extensive laboratory investigations. (4) Inviscid gravity currents propagating in channels; the effect of channel shape and ambient fluid stratification is investigated with a blend of analytical and experimental methods. (5) Hydraulic jump for muds described by a Herschel-Bulkley constitutive equation fluid in channels of given crosssection. (6) Flow of complex fluids in porous and fractured media in confined and free-surface flow, representing environmental contaminants, remediation agents, and fluids used to enhance oil recovery and fracking operations. Closedform solutions are derived and compared with results of laboratory investigations in reconstructed media and Hele-Shaw cells.

Some of the indicated activities are carried out in collaboration with research groups of the University of Parma (Department of Civil, Environmental, Territory Engineering and Architecture).

Main publications

Longo S., Chiapponi L., Di Federico V. (2016). On the propagation of viscous gravity currents of non-Newtonian fluids in channels with varying cross section and inclination, J. of non-Newt. Fl. Mech., dx.doi.org/10.1016/j.jnnfm.2016.07.007.

Ciriello V., Longo S., Chiapponi L., Di Federico V. (2016). Porous gravity currents: a survey to determine the joint influence of fluid rheology and variations of medium properties, Adv. Water Resour. 92, 105-115.

Longo S., Ungarish M., Di Federico V., Chiapponi L., Addona F. (2016). Gravity currents produced by constant and time varying inflow in a circular cross-section channel: experiments and theory, Adv. Water Resour. 90, 10-23.

Daprà I, Scarpi G. (2015). Analytical solution for a Couette flow of a Giesekus fluid in a concentric annulus, J. of non-Newt. Fl. Mech. 223, 221-227.

Longo S., Di Federico V. (2015). Unsteady flow of shear-thinning fluids in porous media with pressure-dependent properties, Transp. Por. Med. 110(3), 429-447.

Longo S., Di Federico V., Chiapponi L. (2015). A dipole solution for power-law gravity currents in porous formations, J. Fl. Mech. 778, 534-551.

Longo S., Di Federico V., Chiapponi L. (2015). Propagation of viscous gravity currents inside confining boundaries: the effects of fluid rheology and channel geometry, Proc. Royal Soc. London- A 471:20150070, 1-21.

Longo S., Ciriello V., Chiapponi L., Di Federico V. (2015). Combined effect of rheology and confining boundaries on spreading of porous gravity currents, Adv. Water Resour. 79, 140-152.

Longo S., Ungarish M., Di Federico V., Chiapponi L., Maranzoni A. (2015). The propagation of gravity currents in a circular cross-section channel: experiments and theory, J. Fl. Mech. 764, 513–537.

Longo S., Di Federico V., Chiapponi L. (2015). Non-Newtonian power-law gravity currents propagating in confining boundaries, Environ. Fl. Mech. 15, 515–535.

Di Federico V., Longo S., Archetti R., Chiapponi L., Ciriello V. (2014). Radial gravity currents in vertically graded porous media: theory and experiments for Newtonian and power-law fluids, Adv. Water Resour. 70, 65-76.

Longo S., Di Federico V., Chiapponi L., Archetti R. (2013). Experimental verification of powerlaw non-Newtonian axisymmetric porous gravity currents, J. Fl. Mech. 731, R2-1-R2-12.

Ciriello V., Longo S., Di Federico V. (2013). On shear thinning fluid flow induced by continuous mass injection in porous media with variable conductivity. Mech. Res. Commun. 52, 101-107.

Ciriello V., Di Federico V. (2013). Analysis of a benchmark solution for non-Newtonian radial displacement in porous media. Int. J. Non-Lin. Mech. 52, 46-57.

Di Federico V., Ciriello V. (2012). Generalized solution for 1-D non-Newtonian flow in a porous domain due to an instantaneous mass injection. Transp. Por. Med. 93, 63-77.

Di Federico V., Archetti R., Longo S. (2012). Spreading of axisymmetric non-Newtonian power- law gravity currents in porous media. J. of non-Newt. Fl. Mech. 189-190, 31-39.

Di Federico V., Archetti R., Longo S. (2012). Similarity solutions for spreading of a twodimensional non-Newtonian gravity current in a porous layer. J. of non-Newt. Fl. Mech. 177-178, 46-53.

Daprà I, Scarpi G. (2011). Pulsatile Poiseuille flow of a viscoplastic fluid in the gap between coaxial cylinders, J. Fluids Eng. 133, 81203 1-7.

Daprà I., Scarpi G. (2010). Unsteady simple shear flow in a viscoplastic fluid: comparison between analytical and numerical solutions. Rheol. Acta 49, 15-22.

Daprà I., Scarpi G. (2009). Couette–Poiseuille flow of the Giesekus model between parallel plates. Rheol. Acta 48, 117-120.

Daprà I., Scarpi G. (2007). Perturbation solution for pulsatile flow of a non-Newtonian Williamson fluid in a rock fracture. Int. J. of Rock Mech. and Mining Sciences 44, 271-278.