Aerodynamic design of nozzles with uniform outflow for hypervelocity ground-test facilities

A method is proposed for the aerodynamic design of nozzles with uniform outflow for supersonic and hypersonic ground-test facilities. This method involves the coupling of an open-source Reynolds-averaged Navier–Stokes computational fluid dynamics solver, Eilmer, with the simplex optimization method of Nelder and Mead for the design of an expanding nozzle contour with the least variations in Mach number and flow angularity. Three nozzles were designed using this method to produce exit flows of Mach 4, Mach 7, and Mach 10. Numerical simulations of the flow in these optimized nozzle contours showed excellent flow uniformity in the core flow; typical Mach number variations were less than 0.5%, flow angularity variations were less than 0.05 deg, static temperature and flow velocity variations were less than 1%, and Pitot and static pressures variations were less than 2%. Experimental surveys of the Pitot pressures at several planes downstream of the exit of the three optimized nozzles showed excellent agreement with numerical simulations. The experimental measurements showed that there were good levels of uniformity in the core flow regions of all three nozzles, thus proving the validity of the proposed design method