Compressible Flow Through a Converging Diverging (CD) Nozzle - Simulation Example


Converging–Diverging (CD) nozzles are used to accelerate compressible flows to supersonic speeds and are commonly used in the propulsion systems of rockets and jet engines. The nozzle has a converging section, a throat (where the cross-sectional area is minimum), and a diverging section. The flow at the nozzle exit is either subsonic or supersonic depending on the nozzle geometry and its inlet–outlet pressure ratios. In this simulation example, we will solve the compressible flow through a 2D axisymmetric CD nozzle and analyze the flow behavior at two different flow conditions.



In this simulation example, you will learn how to simulate a compressible airflow through a converging–diverging nozzle. You will also learn how to set up the model in Ansys Fluent and simulate air flow at two different values of nozzle pressure ratio. These conditions are obtained by varying the inlet pressure of the nozzle.


Download the Mesh file required for setting up the simulation and associated Case and Data files here. Follow the instructions below to set up this simulation in Ansys Fluent starting with the Mesh file. In case you face any issues setting up or running the simulation, refer to the corresponding initial and final Case and Data files.

Alternate video link.

Results and Discussion

Let’s now analyze the results and understand the compressible flow through a CD nozzle.