[alexeym]

@marialhm

Not sure if I get your set up correctly BUT your case is physically unstable, so your results will depend on mesh, discretisation schemes, linear solvers, convergence criteria, turbulence model etc.

I have created example case - https://github.com/mrklein/foam-cases/tree/master/jet - for pimpleFoam. And the results strongly depend on time discretisation and turbulence model.

Here is standard k-epsilon:



Here is k-omega SST



With laminar and realizable k-epsilon (and Crank-Nicolson) we can resolve instability near inlet:



Videos of simulations are collected here: https://www.youtube.com/playlist?lis...WZo4SmJc78aZL5

[marialhm]

Originally Posted by dferrando

You could try with symmetry boundary condition.

Thanks, I will try.

[arjun]

Originally Posted by alexeym

@marialhm

Not sure if I get your set up correctly BUT your case is physically unstable, so your results will depend on mesh, discretisation schemes, linear solvers, convergence criteria, turbulence model etc.

I have created example case - https://github.com/mrklein/foam-cases/tree/master/jet - for pimpleFoam. And the results strongly depend on time discretisation and turbulence model.

Here is standard k-epsilon:



Here is k-omega SST



With laminar and realizable k-epsilon (and Crank-Nicolson) we can resolve instability near inlet:



Videos of simulations are collected here: https://www.youtube.com/playlist?lis...WZo4SmJc78aZL5

Something similar but with mixture multiphase (FVUS Wildkatze) (Notice how unsymmetric it becomes later, but it is transient simulation).

https://www.youtube.com/watch?v=v_y8VejlklQ

[marialhm]

Originally Posted by alexeym

@marialhm

Not sure if I get your set up correctly BUT your case is physically unstable, so your results will depend on mesh, discretisation schemes, linear solvers, convergence criteria, turbulence model etc.

I have created example case - https://github.com/mrklein/foam-cases/tree/master/jet - for pimpleFoam. And the results strongly depend on time discretisation and turbulence model.

Here is standard k-epsilon:



Here is k-omega SST



With laminar and realizable k-epsilon (and Crank-Nicolson) we can resolve instability near inlet:



Videos of simulations are collected here: https://www.youtube.com/playlist?lis...WZo4SmJc78aZL5

Many thanks!!! I watched your video, I got the same results with you, that's why I'm confused.

[marialhm]

Originally Posted by alexeym

@marialhm

Not sure if I get your set up correctly BUT your case is physically unstable, so your results will depend on mesh, discretisation schemes, linear solvers, convergence criteria, turbulence model etc.

I have created example case - https://github.com/mrklein/foam-cases/tree/master/jet - for pimpleFoam. And the results strongly depend on time discretisation and turbulence model.

Here is standard k-epsilon:



Here is k-omega SST



With laminar and realizable k-epsilon (and Crank-Nicolson) we can resolve instability near inlet:



Videos of simulations are collected here: https://www.youtube.com/playlist?lis...WZo4SmJc78aZL5

How can I download your code files?

[alexeym]

Originally Posted by marialhm

How can I download your code files?

You download foam-cases (https://github.com/mrklein/foam-case...ive/master.zip) repository and take jet from there. Or you can clone repository with git instead of downloading zip.