Influence of slip boundary on the hydrofoil with a curved slip boundary condition for the lattice Boltzmann method

摘要

Based on the Navier slip model, a slip boundary format for the lattice Boltzmann method is developed for curve walls of which the shape is well considered. The main idea of this method is to convert the slip length into the slip velocity with a simplified algorithm. With the Navier slip model, the slip velocities at the boundary are obtained through the interpolation of the fluid points near the boundary and are then substituted into the velocity boundary conditions to construct the relationship between the slip length and the macroscopic flow field. This format is free from the restriction of the previous combined boundary conditions which can only be applied to flat boundaries. It also overcomes the limitation that the slip boundary can only simulate flows with small slip length. The present slip boundary condition is implemented for the lattice Bhatnagar-Gross-Krook model, which is verified by several cases, including the cylindrical Couette flow and the irregular Poiseuille flow. The numerical results agree well with theoretical analysis. Furthermore, this boundary condition is applied to the hydrofoil to study the drag reduction effect of the boundary slip phenomenon. It is found that the slip boundary can effectively reduce the drag of the hydrofoil at low Reynolds numbers. Moreover, the position of the slip boundary on the hydrofoil also has significant effects on the lift-to-drag ratio. Published by AIP Publishing.