We study the dynamics of microfluidic fronts driven by pulsatile pressures in the presence of pat... more We study the dynamics of microfluidic fronts driven by pulsatile pressures in the presence of patches of hydrophilic wetting on the walls of the confining media. To do so, we use a recently developed phase-field model that takes inertia into account. We track the interface position in channels with different spacing between the patches and observe that the smaller the spacing, the faster the advancement of the front. We find that the wetting patterning induces a modulating dynamics of the contact line that causes an effective wetting, which in turn determines the modulation of the interface velocity. We characterize the modulation frequency in terms of wetting pattern, inertia, and surface tension, via the capillary pressure, viscosity, and confinement.
We study the dynamics of microfluidic interfaces driven by pulsatile pressures in the presence of... more We study the dynamics of microfluidic interfaces driven by pulsatile pressures in the presence of neutral and hydrophilic walls. For this, we propose a new phase field model that takes inertia into account. For neutral wetting, the interface dynamics is characterized by a response function that depends on a non-dimensional frequency, which involves the time scale associated with inertia. We have found a regime, for large values of this non-dimensional frequency, in which inertia is relevant, and our model is necessary for a correct description of the dynamics. For hydrophilic walls, the dynamics of the contact line with pulsatile forcing is basically undistinguishable to the dynamics of imbibition solely due to wetting. However, we observe that the presence of inertia causes the interface to advance faster than in the absence of pulsatile forcing. This is because pulsatile forcing induces inertia at the bulk to cooperate with wetting creating an enhancement of the imbibition process. We characterize this complex dynamics with transitory exponents that, at early times, are larger than the Washburn ones, and tend to the Washburn exponent at long times, when the interface feels less and less the driving force applied at the entrance of the microchannel, and the dynamics is dominated solely by wetting.
Haemodynamic simulations using one-dimensional (1-D) computational models exhibit many of the fea... more Haemodynamic simulations using one-dimensional (1-D) computational models exhibit many of the features of the systemic circulation under normal and diseased conditions. We propose a novel linear 1-D dynamical theory of blood flow in networks of flexible vessels that is based on a generalized Darcy's model and for which a full analytical solution exists in frequency domain. We assess the accuracy of this formulation in a series of benchmark test cases for which computational 1-D and 3-D solutions are available. Accordingly, we calculate blood flow and pressure waves, and velocity profiles in the human common carotid artery, upper thoracic aorta, aortic bifurcation, and a 20-artery model of the aorta and its larger branches. Our analytical solution is in good agreement with the available solutions and reproduces the main features of pulse waveforms in networks of large arteries under normal physiological conditions. Our model reduces computational time and provides a new approach ...
We analyze the effect that anastomosis has on blood flow. c Details on how anastomosis affects fl... more We analyze the effect that anastomosis has on blood flow. c Details on how anastomosis affects flow are strongly dependent on network geometry. c Flow in a network with anastomosis is determined by its local structure. c Our model is able to interpret the anastomotic effect for tree-like in vivo vasculature networks. c Results are robust to the consideration of the myogenic effect.
We study the dynamics of microfluidic fronts driven by pulsatile pressures in the presence of pat... more We study the dynamics of microfluidic fronts driven by pulsatile pressures in the presence of patches of hydrophilic wetting on the walls of the confining media. To do so, we use a recently developed phase-field model that takes inertia into account. We track the interface position in channels with different spacing between the patches and observe that the smaller the spacing, the faster the advancement of the front. We find that the wetting patterning induces a modulating dynamics of the contact line that causes an effective wetting, which in turn determines the modulation of the interface velocity. We characterize the modulation frequency in terms of wetting pattern, inertia, and surface tension, via the capillary pressure, viscosity, and confinement.
We study the dynamics of microfluidic interfaces driven by pulsatile pressures in the presence of... more We study the dynamics of microfluidic interfaces driven by pulsatile pressures in the presence of neutral and hydrophilic walls. For this, we propose a new phase field model that takes inertia into account. For neutral wetting, the interface dynamics is characterized by a response function that depends on a non-dimensional frequency, which involves the time scale associated with inertia. We have found a regime, for large values of this non-dimensional frequency, in which inertia is relevant, and our model is necessary for a correct description of the dynamics. For hydrophilic walls, the dynamics of the contact line with pulsatile forcing is basically undistinguishable to the dynamics of imbibition solely due to wetting. However, we observe that the presence of inertia causes the interface to advance faster than in the absence of pulsatile forcing. This is because pulsatile forcing induces inertia at the bulk to cooperate with wetting creating an enhancement of the imbibition process. We characterize this complex dynamics with transitory exponents that, at early times, are larger than the Washburn ones, and tend to the Washburn exponent at long times, when the interface feels less and less the driving force applied at the entrance of the microchannel, and the dynamics is dominated solely by wetting.
Haemodynamic simulations using one-dimensional (1-D) computational models exhibit many of the fea... more Haemodynamic simulations using one-dimensional (1-D) computational models exhibit many of the features of the systemic circulation under normal and diseased conditions. We propose a novel linear 1-D dynamical theory of blood flow in networks of flexible vessels that is based on a generalized Darcy's model and for which a full analytical solution exists in frequency domain. We assess the accuracy of this formulation in a series of benchmark test cases for which computational 1-D and 3-D solutions are available. Accordingly, we calculate blood flow and pressure waves, and velocity profiles in the human common carotid artery, upper thoracic aorta, aortic bifurcation, and a 20-artery model of the aorta and its larger branches. Our analytical solution is in good agreement with the available solutions and reproduces the main features of pulse waveforms in networks of large arteries under normal physiological conditions. Our model reduces computational time and provides a new approach ...
We analyze the effect that anastomosis has on blood flow. c Details on how anastomosis affects fl... more We analyze the effect that anastomosis has on blood flow. c Details on how anastomosis affects flow are strongly dependent on network geometry. c Flow in a network with anastomosis is determined by its local structure. c Our model is able to interpret the anastomotic effect for tree-like in vivo vasculature networks. c Results are robust to the consideration of the myogenic effect.
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Papers by Joaquín Flores