Ciencias con mención en Física

Permanent URI for this collectionhttp://98.81.228.127/handle/20.500.12404/15958

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    Análisis de estabilidad de frentes químicos en reacciones exotérmicas
    (Pontificia Universidad Católica del Perú, 2021-02-16) Quenta Raygada, Johann Sebastián; Vásquez Rodríguez, Desiderio Augusto
    Buoyancy-driven convection is a phenomenon that appears in a wide range of natural processes, from atmospheric and oceanic flows to the Earth’s core inner dynamics. In particular, convective flows are ubiquitous in systems of chemical substances reacting at an interface known as a reaction front. Autocatalytic reaction fronts allow for different types of instabilities due to gradients in chemical composition and the exothermicity of the reaction. In order to study the effects of thermal gradients in such systems, we develop a model for thin-front propagation in two-dimensional tubes. Temperature and front evolution are coupled to two different descriptions of the system’s hydrodynamics: Darcy’s law and the Navier-Stokes equations for viscous flows. We study the stability of the convectionless flat front by carrying out a linear stability analysis. The regimes for which convection arises will depend on a control parameter, called the thermal Rayleigh number, which measures the strength of thermal gradients in the system. We vary this parameter between positive and negative values and analyze its effects on the stability of the fronts.
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    Efectos de dispersión lineal y advección por flujo externo en frentes en propagación
    (Pontificia Universidad Católica del Perú, 2020-09-02) Martínez Rodríguez, Andrés Alfredo; Vilela Proaño, Pablo Martin
    Kuramoto-Sivashinsky equation in a two dimensional slab with infinite walls and advection by external flow is considered. Stationary front solutions were then found using the shooting method with simple Euler method and oscillatory front solutions were solved with simple Euler method. Numerical results for both were analyzed, finding the solutions for stationary fronts including external flow, Couette and Poiseuille. A modified Kuramoto-Sivashinsky equation, similar to the equation used to described solitary waves was also considered and the effect it had on stationary fronts with and without external flow was also explored. For oscillatory solutions, the front profiles and the phase space diagrams were calculated, a bifurcation diagram was also analyzed for no external flow as well as for fronts advected by Poiseuille and Couette external flow, and good agreement with Feigenbaum’s number was found in all cases.