Quasi-1D Unsteady Nozzle Shock Solver

This simulator time-marches the unsteady quasi-1D Euler equations — real conservation of mass, momentum and energy in a converging-diverging duct — using an explicit finite-volume scheme with a Rusanov numerical flux. Instead of solving the steady-state isentropic and Rankine-Hugoniot relations algebraically and drawing the answer, the shock here actually forms and settles from the time-evolving flow field itself, exactly like a real CFD nozzle solver. Drag the back-pressure ratio or exit area ratio and watch the shock visibly slide to its new equilibrium position over several seconds of simulated time, rather than jumping there instantly.