Vol. 1 No. 2 (2020): Suplemento de la Revista Mexicana de Física. XXV Congress of the Fluid Dynamics Division
The XXV Congress of the Fluid Dynamics Division was held in Quer´etaro from November 5 to 8, 2019, at the el Centro Cultural, Casa de la Cultura Fundaci´on UNAM.
Guest Editors:
Alberto Beltr´an Morales, Instituto de Investigaciones en Materiales, Unidad Morelia, UNAM.
Rosanna Bonasia, CONACyT - Instituto Polit´ecnico Nacional, SEPI ESIA-UZ.
Anne Cros, Dep. F´ısica, CUCEI, Universidad de Guadalajara.
Josu´e R. Hern´andez Ju´arez, IPN-ESIME-Azcapotzalco.
Carlos M´alaga, Departamento de Física, Facultad de Ciencias, UNAM.
02 XXV Congress of the Fluid Dynamics Division
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Flow around a Wingmill device for energy extraction
Abstract:The dynamics of a closed loop self controlled underwater oscillating foil device for energy extraction (a wingmill) is studied through numerical simulations. The viscous two and three dimensional flow around the foil was computed using OpenFOAM and a Lattice-Boltzmann Equation model, respectively. Heaving is driven by the computed hydrodynamic lift and a damper, that extracts energy, while pitching is driven by the hydrodynamic torque and a feedback control torque that leads the foil to a given angle of attack. Unlike most of the related work found in the literature, the heaving and pitching motion of the foil is not prescribed. Dimensional analysis suggests a compromise between the generator and control gains, so a parametric study was carried out. The effect of a three dimensional finite wingspan on the performance of the device, and the flow is compared with the two dimensional case. This fully coupled fluid-solid-body interaction configuration will allow for the system identification, control and optimization of energy harvesting devices in future studies.⬇️ Scroll down to see the full summary -
On a general correlation for the discharge rate of grains through slots in sidewalls of silos due to gravity
Abstract:⬇️ Scroll down to see the full summaryIn this work we discuss the general validity of a phenomenological correlation for the mass flow rate of dry non cohesive granular material that outflows, due to the gravity, from slots in very thin vertical sidewalls of bins. The correctness of such a formula is analyzed by comparing it to other correlations published elsewhere which reports cases of very large, similar and very small channel width W relative to its length D.
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Characterization of an interstitial current model around a cancer nodule using optical tweezers.
Abstract:Currently, the process of diagnosis and treatment of a patient with metastatic cancer is highly inefficient due to the complexity of the disease (metastasis is the spread of cancer cells from a primary tumor to secondary tumors at distant sites [1]). However, recent studies have shown that shear stress, caused by natural microfluidic currents, causes cancer cells to break away, spreading them to secondary sites [2] and aggravating the disease. The extent of shear stress on nodules due to microfluidic currents has not been experimentally proven. In the present study, a methodology developed to induce local shear stresses on a cancer nodule model from velocity field measurements is presented. Such methodology is based on the use of the optical tweezers velocimetry technique reported by Eom, et al. [3] and Almendarez, et al. [4]. The methodology consists on using the holographic optical tweezers velocimetry technique (i.e. multiple trapping in one domain), in order to measure, in a discretized way, the flow field at different positions, and approximate through least squares the velocity profiles; with such information, the shear stresses on the surface of the nodule model will be approximated. The methodology contributes to the understanding of metastasis process and other applications, such as: the development of thrombosis, tumor formation, stopping bleeding, etc.⬇️ Scroll down to see the full summary -
Numerical simulation of a polymer melting process using solar energy
Abstract:In this work, the melting process of a polymeric material is numerically investigated. In general, the heat required for melting plastics is obtained throughout electrical resistances or by burning fossil fuels. The heat transfer mechanisms of these common practices correspond to conduction and convection, respectively. This work explores the feasibility of using radiation as the primary mechanism of energy supply, which has not been widely studied. The energy to achieve the phase change from solid to liquid can be obtained by concentrated solar energy radiation. The total energy required is calculated solving the energy equation using the enthalpy formulation. An explicit formulation with an enthalpy linearization was implemented in the Mathematica programming language and compared with the solution in the commercial softwares Ansys Fluent and COMSOL Multiphysics showing a good agreement. Based upon numerical predictions, it is examined the effects of the relevant parameters, such as incident radiation and convective heat transfer coefficient, on the melting process. It is observed that under weather conditions commonly attained in different cities worldwide, with a radiation of 1000 W/m$^2$ and low convective losses with $h=8$ W/m$^2\cdot$K, the melting process of a cylindrical rod of 3/4 inches diameter can be carried out in around 2 hours.⬇️ Scroll down to see the full summary -
Permeability simulation in an elastic deformable sandstone under stress changes
Abstract:⬇️ Scroll down to see the full summaryFluid flow and rock mechanics become coupled in various important phenomena in Geosciences. In order to study this coupling, laboratory work has been carried out in triaxial cells along the years for various rock and fluid types at different confinement stress and pore pressure conditions. In a similar way, poromechanic models have been developed to simulate them, in which constitutive porosity and permeability correlation models in terms of strain, stress and fluid pressure have to be provided. However, to date, the applicability of the available correlation models to describe this phenomenon in different types of rock remains to be analyzed. In this work, a single-phase poroelastic model is applied to simulate a published geomechanical test performed in sandstones to examine the capacity of commonly used constitutive porosity and permeability correlations to describe the behavior of a homogeneous poroelastic medium. After discussing the results, we conclude that for this sandstone, the best permeability constitutive correlation model is Walder and Nur.
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Proceso de descarga de un silo como una línea continua de ruido
Abstract:⬇️ Scroll down to see the full summaryDurante el proceso de descarga de un material granular desde un silo, pueden surgir fenómenos de resonancia como la emisión de ondas acústicas. Esta contribución acústica es debida a la fricción entre los granos y la pared del silo acoplada con la generación y amplicación de ondas macánicas. En este trabajo se presentan algunos resultados experimentales correspondientes al proceso de descarga del silo considerado como una línea continua de ruido donde los patrones de radiación de la energía acústica dan cuenta de los efectos adversos como la contaminación acústica. Se propone que estos resultados son un análisis alternativo para evitar efectos acústicos no deseados en el proceso de descarga de silos.
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Liquid metal MHD flow and heat transfer in a rectangular duct with perfectly conducting walls perpendicular to the applied magnetic field
Abstract:Several technological applications involve the flow of liquid metals in ducts under a magnetic field, for instance, the coolants of fusion reactors. In this paper, using a magnetohydrodynamic MHD formulation based on the electric potential, we obtain an analytical solution for the flow of a liquid metal in a rectangular duct with two insulating walls and two perfectly conducting walls perpendicular to the applied uniform magnetic field. As the Hartmann number increases, the flow displays high velocities in the boundary layers attached to the insulating walls and a quasi-stagnant flow at the core. The effect of this flow pattern on the forced convection heat transfer is then explored numerically considering a uniform heat flux on either the conducting or insulating walls. Compared to the hydrodynamic case, the MHD flow enhances the heat transfer as the Hartmann number increases only in the case when the heat flux is applied at the insulating walls where high velocities are present. The increase of the local Nusselt number as the Péclet number grows indicates an efficient heat removal from the heated wall.⬇️ Scroll down to see the full summary -
Experimental study of capillary penetration in rectangular Hele-Shaw cells closed by two edges
Abstract:⬇️ Scroll down to see the full summaryHere is studied the capillary penetration of a viscous liquid between two vertical, rectangular close together plates. In experiments the plates were joined simultaneously along two edges, and the liquid has penetrated from the bottom. Spacers with different geometries like circular, triangular and rectangular shape, were used to check their aects on the rise proles in a dynamic way, it was noticed that when time evolves, the proles are stabilized in a catenary and the instabilities induced by efforts present in the plates disappear. Also, it is observed a rate of ascent that diers of classical values of t^1/3 or t^1/2, depending of gravity effect.
