# 'Compressible Flow: de Laval Nozzle' simulation project by sjoshi

#1

I created a new simulation project called 'Compressible Flow: de Laval Nozzle':

This project simulates compressible turbulent flow through a de Laval nozzle.

More of my public projects can be found here.

#2

@sjoshi: Hi Saumitra. I am trying to simulate an isentropic supersonic flow in a De Laval Nozzle, but it seems that it is not that easy to get a stable solution. It would be a very kind of you taking a look at the following project and giving me some guidelines: https://www.simscale.com/projects/roozbehmousavi/de_laval_nozzle
P.S.: Although the compressible flow formulations are available, but I simply used the following web-based calculator to determine the flow conditions: http://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.html

#3

Hello @roozbehmousavi!

After exploring the case you shared in your post, it appears that a “Fixed value” boundary condition has been used for temperature at the Walls. I would recommend trying out the “Set gradient to zero” boundary condition, since typically the temperature at the wall might not always have a uniform value over the entire length of the nozzle.

Please let me know if this solves the issue. If not, we can discuss other options.

#4

Hi @sjoshi. Thanks for your answer. I applied your suggestion, but still the solution does not converge. Anyway, as you mentioned, I guess there is something wrong with the temperature because I need to reduce the under relaxation factor of h down to 0.001 in order to get some iterations before the divergence! I am not that expert in gas dynamics, but don’t you think if I need to use higher values of temperature in such a range of Mach number? I would like to get M=2 at the outlet.

#5

For detailed study please go to Compressible Flow: de Laval Nozzle documentation.

#6

Hi,

I went through your "De Laval" project and found a face named "defaultFace". I couldnt understand the purpose of this face. Can you please explain me the use of this defaultFace ?

#7

Hello,

I checked the mesh, and the entity set named "defaultFace" is empty. It was probably from the mesh algorithm that would put every face without an entity set on this last entity set. However, since there is no face without an entity set, this entity set is empty. Therefore, there is no actual use for this entity set.