| dc.description.abstract | Supersonic wind tunnels are a critically important engineering tool used to make aerodynamic discoveries and technological advancements in the high speed flight regime. Great care must be taken when designing the nozzle for a supersonic wind tunnel, as the quality of data produced throughout the lifetime of the facility depends on the quality of the nozzle contour. A nozzle design code was developed to expand the capabilities of the National Aerothermochemistry and Hypersonics Labratory, permitting the timely creation of new nozzles that feature elongated flow expansion near the throat. The foundation of the code is a hyperbolic partial differential equation governing irrotational, inviscid, adiabatic flow inside a nozzle, derived from governing principles of gas dynamics. This equation was reduced, through the method of characteristics, to a system of ordinary differential equations which are solved along characteristic lines with the modified Euler predictor-corrector method for flow parameters inside of the diverging section of the nozzle. The code generates a nozzle based on the user’s desired throat height, radius of curvature of the circular throat region, turning angle of the circular region, and Mach number. The code outputs a fully defined nozzle contour. Computational fluid dynamics simulations were performed for several de- signed contours to validate the code. A grid convergence study was performed, followed by a study of the effect of the initial-value line Mach number input on nozzle performance. Simulations of selected nozzles were performed to quantify the code’s performance, including a short and long converging-diverging nozzle to demonstrate the unique capability of the code. Aerodynamically- uniform flow was produced for all test cases, which resulted in a successful MOC code. A recommendation was made to couple a CFD solver with an optimization algorithm to produce hypersonic nozzles contours corrected for viscous effects induced at higher Mach numbers. | en |
