Скачать или смотреть Axisymmetric Minimum Length Nozzle Start - Inviscid Flow

Transient simulation of air flowing through an axisymmetric minimum-length nozzle (Ansys FLUENT). Compressible, inviscid flow. The animation shows Mach number contours.

The total pressure is 5 atm, and the total temperature is 3100 K; ambient pressure and temperature are 101325 Pa and 300 K, respectively. The elapsed time is 7.8 milliseconds.
I used a quadrilateral mesh for spatial discretization and a second-order upwind scheme for time integration. Courant number is 1, the time step of integration is set to 1 microsecond. A pressure-outlet, non-reflecting boundary condition was set at the right boundary of the domain.

The geometry of the divergent section of the nozzle was designed with the axisymmetric method of characteristics using a Matlab function:

Ludovico Fossà (2021). Axisymmetric Minimum Length Nozzle Design Tool (https://www.mathworks.com/matlabcentr..., MATLAB Central File Exchange. Retrieved January 9, 2021.

I assumed the geometry of the convergent section to be somewhat arbitrary. I simply drew a circular arc followed by two straight lines to connect the throat section to the inlet.