Quiescent Fluid

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Maurizio Porfiri - One of the best experts on this subject based on the ideXlab platform.

  • energy transfer between a passing vortex ring and a flexible plate in an ideal Quiescent Fluid
    Journal of Applied Physics, 2015
    Co-Authors: Maurizio Porfiri, Sean D Peterson
    Abstract:

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise Quiescent Fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the Fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.

  • experiments on the water entry of asymmetric wedges using particle image velocimetry
    Physics of Fluids, 2015
    Co-Authors: Adel Shams, Mohammad Jalalisendi, Maurizio Porfiri
    Abstract:

    In this work, we experimentally characterize the water entry of an asymmetric wedge into a Quiescent Fluid through particle image velocimetry (PIV). The wedge enters the water surface with an orthogonal velocity falling from a fixed height. We systematically vary the heel angle to elucidate the effect of asymmetric impact on the flow physics and on the Fluid-structure interaction. The pressure field in the Fluid is reconstructed from PIV data by integrating the Poisson equation. We find that the impact configuration significantly influences both the velocity and the pressure field, ultimately, regulating the hydrodynamic loading on the wedge. Specifically, as the heel angle increases, the location of maximum velocity of the flow moves from the pile-up region to the keel. At the same time, the pressure field significantly decreases in the vicinity of the keel, reaching values smaller than the atmospheric pressure. The spatiotemporal evolution of the hydrodynamic loading is thus controlled by the heel angle, with larger heel angles resulting into more rapid and sustained impacts.

  • Evaluation of the pressure field on a rigid body entering a Quiescent Fluid through particle image velocimetry
    Experiments in Fluids, 2013
    Co-Authors: Riccardo Panciroli, Maurizio Porfiri
    Abstract:

    The objective of this work is to verify the accuracy of indirect pressure measurement from particle image velocimetry in water entry problems. The pressure is evaluated by solving the incompressible Navier–Stokes equations, whose kinematic components are estimated from particle image velocimetry. We focus on the water entry of a rigid wedge, for which we explore variations of the entry velocity. Experimental results are verified through comparison with well-established analytical formulations based on potential flow theory. Our findings demonstrate the feasibility of accurately reconstructing the hydrodynamic pressure field over the entire duration of the impact. Along with a thorough experimental validation of the method, we also offer insight into experimentally relevant factors, such as the maximum resolved Fluid velocity and the required spatial integration area.

  • energy exchange between a vortex ring and an ionic polymer metal composite
    Applied Physics Letters, 2012
    Co-Authors: Sean D Peterson, Maurizio Porfiri
    Abstract:

    In this letter, we study the transient response of a cantilevered ionic polymer metal composite impacted by a self-propagating vortex ring in an otherwise Quiescent Fluid. Experiments are performed using time-resolved particle image velocimetry to elucidate the flow physics during the vortex ring propagation and subsequent interaction with the cantilever. Images from these experiments are analyzed to extract the vibration of the structure, which is used to estimate the energy transferred from the vortex ring. A small fraction of this energy is further transduced into an electrical signal by the chemoelectromechanical behavior of the ionic polymer metal composite.

  • interaction of a vortex pair with a flexible plate in an ideal Quiescent Fluid
    Journal of Intelligent Material Systems and Structures, 2012
    Co-Authors: Sean D Peterson, Maurizio Porfiri
    Abstract:

    The coupled interaction of a cantilevered Kirchhoff–Love plate with two vortex filaments of equal and opposite circulation in an infinite incompressible, inviscid, and irrotational Fluid domain is investigated. The vortices initially advect toward the cantilevered plate, which is oriented perpendicular to the direction of propagation of the vortex pair and undergoes cylindrical bending. As the pair approaches the plate, the pressure field induced by the vortices deflects the plate and initiates vibration of the structure. The vibration of the structure, in turn, alters the path of the two vortices. The level of interaction depends on the vortex circulation and on the ratio of the plate inertia to the Fluid inertia, termed the mass ratio. In general, the vortices tend to pass around the plate and eventually advect away from the plate, albeit with a modified trajectory, which depends on the strength of the Fluid and structure coupling. The energy imparted to the plate increases with increasing vortex circul...

Sauro Succi - One of the best experts on this subject based on the ideXlab platform.

  • a moving grid approach for Fluid structure interaction problems with hybrid lattice boltzmann method
    Computer Physics Communications, 2019
    Co-Authors: G Di Ilio, Stefano Ubertini, Daniele Chiappini, Gino Bella, Sauro Succi
    Abstract:

    Abstract In this paper, we propose a hybrid lattice Boltzmann method (HLBM) for solving Fluid–structure interaction problems. The proposed numerical approach is applied to model the flow induced by a vibrating thin lamina submerged in a viscous Quiescent Fluid. The hydrodynamic force exerted by the Fluid on the solid body is described by means of a complex hydrodynamic function, whose real and imaginary parts are determined via parametric analysis. Numerical results are validated by comparison with those from other numerical as well as experimental works available in the literature. The proposed hybrid approach enhances the capability of lattice Boltzmann methods to solve Fluid dynamic problems involving moving geometries.

  • particle shape influences settling and sorting behavior in microFluidic domains
    Scientific Reports, 2018
    Co-Authors: Hakan Basagaoglu, Sauro Succi, Danielle Y Wyrick, Justin Blount
    Abstract:

    We present a new numerical model to simulate settling trajectories of discretized individual or a mixture of particles of different geometrical shapes in a Quiescent Fluid and their flow trajectories in a flowing Fluid. Simulations unveiled diverse particle settling trajectories as a function of their geometrical shape and density. The effects of the surface concavity of a boomerang particle and aspect ratio of a rectangular particle on the periodicity and amplitude of oscillations in their settling trajectories were numerically captured. Use of surrogate circular particles for settling or flowing of a mixture of non-circular particles were shown to miscalculate particle velocities by a factor of 0.9-2.2 and inaccurately determine the particles' trajectories. In a microFluidic chamber with particles of different shapes and sizes, simulations showed that steady vortices do not necessarily always control particle entrapments, nor do larger particles get selectively and consistently entrapped in steady vortices. Strikingly, a change in the shape of large particles from circular to elliptical resulted in stronger entrapments of smaller circular particles, but enhanced outflows of larger particles, which could be an alternative microFluidics-based method for sorting and separation of particles of different sizes and shapes.

Ming Zhao - One of the best experts on this subject based on the ideXlab platform.

Sean D Peterson - One of the best experts on this subject based on the ideXlab platform.

  • energy transfer between a passing vortex ring and a flexible plate in an ideal Quiescent Fluid
    Journal of Applied Physics, 2015
    Co-Authors: Maurizio Porfiri, Sean D Peterson
    Abstract:

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise Quiescent Fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the Fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.

  • energy exchange between a vortex ring and an ionic polymer metal composite
    Applied Physics Letters, 2012
    Co-Authors: Sean D Peterson, Maurizio Porfiri
    Abstract:

    In this letter, we study the transient response of a cantilevered ionic polymer metal composite impacted by a self-propagating vortex ring in an otherwise Quiescent Fluid. Experiments are performed using time-resolved particle image velocimetry to elucidate the flow physics during the vortex ring propagation and subsequent interaction with the cantilever. Images from these experiments are analyzed to extract the vibration of the structure, which is used to estimate the energy transferred from the vortex ring. A small fraction of this energy is further transduced into an electrical signal by the chemoelectromechanical behavior of the ionic polymer metal composite.

  • interaction of a vortex pair with a flexible plate in an ideal Quiescent Fluid
    Journal of Intelligent Material Systems and Structures, 2012
    Co-Authors: Sean D Peterson, Maurizio Porfiri
    Abstract:

    The coupled interaction of a cantilevered Kirchhoff–Love plate with two vortex filaments of equal and opposite circulation in an infinite incompressible, inviscid, and irrotational Fluid domain is investigated. The vortices initially advect toward the cantilevered plate, which is oriented perpendicular to the direction of propagation of the vortex pair and undergoes cylindrical bending. As the pair approaches the plate, the pressure field induced by the vortices deflects the plate and initiates vibration of the structure. The vibration of the structure, in turn, alters the path of the two vortices. The level of interaction depends on the vortex circulation and on the ratio of the plate inertia to the Fluid inertia, termed the mass ratio. In general, the vortices tend to pass around the plate and eventually advect away from the plate, albeit with a modified trajectory, which depends on the strength of the Fluid and structure coupling. The energy imparted to the plate increases with increasing vortex circul...

Juan C Lasheras - One of the best experts on this subject based on the ideXlab platform.

  • effect of preferential concentration on the settling velocity of heavy particles in homogeneous isotropic turbulence
    Journal of Fluid Mechanics, 2002
    Co-Authors: Alberto Aliseda, Alain H Cartellier, F Hainaux, Juan C Lasheras
    Abstract:

    The behaviour of heavy particles in isotropic, homogeneous, decaying turbulence has been experimentally studied. The settling velocity of the particles has been found to be much larger than in a Quiescent Fluid. It has been determined that the enhancement of the settling velocity depends on the particle loading, increasing as the volume fraction of particles in the flow increases. The spatial and temporal distribution of the particle concentration field is shown to exhibit large inhomogeneities. As the particles interact with the underlying turbulence they concentrate preferentially in certain regions of the flow. A characteristic dimension of these particle clusters is found to be related to the viscous scales of the flow. Measurements of the settling velocity conditioned on the local concentration of particles in the flow have shown that there is a monotonic increase in the settling velocity with the local concentration (the relation being quasi-linear). A simple phenomenological model is proposed to explain this behaviour

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