Numerical investigation on applications simulated via using lattice boltzmann method

• Autores: Bo An
• Directores de la Tesis: Josep M. Bergadà Grañó (dir. tes.), Fernando Mellibovsky (codir. tes.)
• Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2019
• Idioma: español
• Tribunal Calificador de la Tesis: Antoni Pujol Sagaró (presid.), Sebastian Altmeyer (secret.), Joan Herrero Sabartés (voc.)
• Programa de doctorado: Programa de Doctorado en Ingeniería Mecánica, Fluidos y Aeronáutica por la Universidad Politécnica de Catalunya
• Materias:
  • Matemáticas
    • Ciencia de los ordenadores
      • Simulación
    • Análisis numérico
      • Ecuaciones diferenciales
  • Física
    • Física de fluidos
      • Flujos de fluidos
    • Mecánica
      • Mecánica de fluidos
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• Resumen

  • The present doctoral thesis is about the numerical investigation simulated via using lattice Boltzmann method (LBM), the applications cover a large scale of subjects, including 1. Mathematical-physical equations A new lattice Boltzmann method (LBM) 9-bit model is presented to solve mathematical-physical equations, such as, Laplace equation, Poisson equation, Wave equation and Burgers equation. The main benefits of the new model proposed is that is faster than the previous existing models and has a better accuracy.

    2. Lid-driven isosceles right-angled triangular cavity We employ lattice Boltzmann simulation to numerically investigate the two-dimensional incompressible ¿ow inside a right-angled isosceles triangular enclosure driven by the tangential motion of its hypotenuse. We analyze the bifurcation sequence that takes the ¿ow from steady to periodic and then quasi-periodic and show that the invariant torus is ¿nally destroyed in a period-doubling cascade of a phase-locked limit cycle. As a result, a strange attractor arises that induces chaotic dynamics.

    3. Improvements for the numerical stability of original LBM In order to study the flow behavior at high Reynolds numbers, two modified models, known as the multiple-relaxation-time lattice Boltzmann method (MRT-LBM) and large-eddy-simulation lattice Boltzmann method (LES-LBM), have been employed. The MRT-LBM was designed to improve numerical stability at high Reynolds numbers, by introducing multiple relaxation time terms, which consider the variations of density, energy, momentum, energy flux and viscous stress tensor. The LES-LBM model implements the large eddy simulation turbulent model into the conventional LBM, allowing to study the flow at turbulent Reynolds numbers. LES-LBM combined with Quadruple-tree Cartesian cutting grid (tree grid) was employed for the first time to characterize the flow dynamics over a cylinder and a hump, at relatively high Reynolds numbers.