Flow simulations around circular cylinders by Lattice Boltzmann Method at moderate Reynolds number

Abstract

In this thesis, Lattice Boltzmann Method is used to simulate the flow. Firstly, lid-driven square cavity flow is simulated to check the validity of Lattice Boltzmann Method. Both of Single-Relaxation-Time and Multi-Relaxation-Time Lattice Boltzmann Method has been used. The numerical advantage of MRT model over SRT model is discussed. Simulations of flow past a circular cylinder are carried out at moderate Reynold number Re = 100 to 300. Different types of boundary conditions are studied for better stability and accuracy of the computation. Far field boundary condition is implemented to obtain the accurate results without disturbance of bounce-back flow from the walls. The resulting drag and lift coefficients are compared with the other researchers’ numerical and experimental results. The tandem arrangement between two circular cylinders is then set up to reduce the vortex shedding. The flow characteristics are analyzed according to the separation of the two cylinders. FORTRAN Computer Programming Language is used to write the code for simulations.