The importance of the accuracy of the experimental environment is obvious for experimental flow conditions that are difficult to obtain. Wind tunnels are used to accomplish these conditions for such experiments. Wind tunnels can be classified as fixed and variable geometry nozzle. Since more than one fixed-geometry nozzle will be required to different high Mach numbers, the convenience of using variable-geometry nozzles in this area is obvious. However, calculating the number of actuators that will need to be used in the flexible wall nozzles that come with these conveniences and obtaining the correct shape curve is a problem. This project aims to create a reliable and accurate shape optimization for flexible plate nozzles used in supersonic wind tunnels. In order for this project to be reliable, the optimized nozzles must be shock-free, have uniform flow, and have a low standard deviation of exit Mach. There are several well established albeit time-consuming and imprecise methods for shape optimization of a supersonic nozzles. Other more recently developed methods require high computational capacity and are highly dependent on the ability of the operating analyst.
For this optimization study, firstly, Method of Characteristics (MOC) and Sivells geometries were obtained for certain Mach numbers. The boundary conditions were determined and flow calculations using one dimensional isentropic flow equations were peformed. Two-dimensional Computational Fluid Dynamics (CFD) analysis were then performed on the obtained geometries. Following the analysis the uniformity and Mach number of the output flow were checked. Optimization studies were carried out with the selected optimization methods. The optimized nozzle geometry was compared for the different methods, the optimum result was used to run a 3D analysis. The forces acting on the nozzle wall were obtained. Using these forces a structural analysis to find reaction forces acting on the actuators was performed. An optimization to limit forces acting on the actuators was carried out. A 3D design of the nozzle was constructed and technical drawings were obtained. A cost analysis for the construction of the entire nozzle set-up was performed.