Abstract
This paper presents the design of injection duct with height distribution control for co-flow jet (CFJ) flow control airfoils in cruise condition. The duct cross section outlines are mathematically modeled as superellipse with a duct height control parameter c(Z, L). The injection duct height distribution is of great importance to the overall performance of the duct and the CFJ airfoil. The aerodynamic performance of the ducts and the CFJ airfoils are evaluated via numerical simulations, which employ 3D RANS solver with Spalart-Allmaras (S-A) turbulence model, 3th order WENO scheme for the inviscid fluxes, and 2nd order central differencing for the viscous terms. The design goal is to eliminate flow separation at the CFJ airfoil edges, maximize the corrected aerodynamic efficiency (C-L/C-D)c of the CFJ airfoil. Results show that the injection duct height distribution control effectively removes flow separation at the airfoil edges. The best design presents 39% improvement of C-L/C-D and 16.4% improvement of (C-L/C-D)c.