Three coflow jet airfoils with twice-doubled injection-slot sizes are calculated using a Reynolds-averaged Navier-Stokes computational fluid dynamics solver with the one-equation Spalart-Allmaras model. At the same angle of attack, the twice-larger injection-slot-size airfoil passes the (about twice-greater) jet mass flow rate, with the momentum coefficients also nearly doubled. The coflow jet airfoil with the largest slot size has the least stall angle of attack. When the injection-slot size is reduced from the maximum by half, the stall angle of attack and the maximum lift coefficient are increased. When the injection-slot size is further reduced by half, the stall angle of attack is still increased, but the maximum lift coefficient is lower due to the smaller momentum coefficient. The trends of the stall angle of attack and maximum lift coefficient agree with the experiment. At low angles of attack, both the computed lift and drag coefficients agree fairly well with the experiment. At high angles of attack, the lift and drag are underpredicted. The reason may be that the Reynolds-averaged Navier-Stokes model cannot handle the turbulence mixing at high angles of attack.
ASJC Scopus subject areas
- Aerospace Engineering