Heat Transfer and Flow Around Starfish-Inspired Cylinder by Immersed Boundary-Simplified Thermal Lattice Boltzmann Method

This study investigates the structure of flow and heat transfer around the starfish-inspired cylinder. The shape of the starfish-inspired cylinder is evolved from the circular cylinder by changing one parameter (tuber length) in the math formula. The numerical simulations are performed by the new numerical scheme, which is immersed boundary-simplified thermal lattice Boltzmann method (IB-STLBM). The effects of tuber length (2 ≤ m ≤ 4), angle of attack (0 ≤ θ ≤ 1/5π), and Reynolds number (40 ≤ Re ≤ 100) on the flow pattern and heat transfer characteristics are analyzed. In the process of changing considered parameters, five different structures can be obtained: steady separated flow, unsteady trailing-edge separated flow, unsteady leading-edge separated flow, unsteady one-bubble separated flow and unsteady two-bubble separated flow. For the cases which are unsteady and asymmetrical, Cd mean , Cd rms , Cl mean , Cl rms , Nu mean and Nu rms has a positive function of m . At Re = 40, Cd mean increases initially and decreases afterward with increasing θ . However, for Re = 70 or 100, Cd mean decreases and Nu mean rises as the increment of θ