An Extended Lattice Boltzmann Approach to Simulate Multi‐Cylinder Configured High‐Speed Compressible Fluid Flows

ABSTRACT The present study is focused on several numerical experiments on high‐speed compressible fluid flows inside a long horizontal multi‐cylinder positioned channel using a double distribution function based extended lattice Boltzmann (LB) approach. Initially, an algorithm of the lattice Boltzmann approach to simulate the compressible flows is developed and stabilized by introducing the Lagrange multipliers approach to calculate the equilibrium distribution function, Knudsen‐number‐dependent relaxation time, and large adaptive stencils in the velocity discretization scheme. Subsequently, the algorithm/code is validated by comparison of the present results against the existing benchmark results. The LB simulations are carried out at the supersonic state for two different Mach numbers, 1.5 and 1.7. The channel is enclosed from the top and bottom sides, with surfaces having symmetric boundary conditions. At the inlet and outlet, Dirichlet and Neumann boundary conditions are employed, respectively, for density, velocity, temperature, and pressure. Three different studies based on the configuration of the multi‐cylinders are carried out. Inside the channel, the multi‐cylinders are either positioned in a tandem manner, vertical (side‐by‐side) manner, or staggered manner with varying angles of incidences. Various physical parameters like the coefficient of pressure, drag and lift coefficient, temperature flow field, and so forth, are computed and reported throughout the study.