Study of an asymmetric flap nozzle as a thrust-vectoring device

Abstract

The problem of isentropic flow through an asymmetric two-dimensional convergent nozzle as a thrustvectoring device has been solved by the method of hodograph transformation coupled with finite-difference computation. With the given appropriate flow parameters, the solution was first established in the hodograph domain. The corresponding nozzle configuration and the flowfield properties were subsequently obtained through direct integration. The thrust-vectoring performance corresponding to specific nozzle geometries were also determined and presented. Experiments for specific nozzle configurations were also conducted to obtain pressure data along the nozzle walls for verification purposes. The numerical results were found to be in good agreement with the experimental data. Nomenclatureof approaching uniform flow h E -thickness of asymtoptic uniform flow M = Mach number M* = Mach number based on critical sound speed p = pressure q = transformed velocity s = distance along nozzle wall T -thrust force V = velocity magnitude x,y = physical coordinates MU^L = upper and lower flap angles J3 -dimensionless flow angle 7 = specific heat ratio d = thrust angle 0 = flow angle p = density <t > = potential function i/' = stream function a; = dimensionless velocity Subscripts A E E 0 = approaching uniform flow -asymtoptic uniform flow (for subcritical flow) = critical point on sonic line (for supercritical flow) = stagnation condition = freestream condition