1. Description of the example

SMC (Simple Metal Chevron) series nozzles are experimental model nozzles designed to study jet noise and flow characteristics. 

Its simplified design makes it easier to compare and verify experimental results and numerical simulation results, thereby improving the reliability and accuracy of the study.

On the basis of its own fast and high-precision LES solver, Dimaxer has added a far-field noise prediction function based on FW-H Surface.

In this paper, the 6-tooth SMC001 nozzle is selected to demonstrate Dimaxer's ability to simulate transonic jets.

2. Calculation settings

2.1 Computing grids

The computational mesh is generated using an overlapping grid, and the background grid is locally encrypted. The total number of meshes is 1.2M, and the solution points can reach 76.8M with fourth-order precision.

2.2 Boundary Conditions

The outer boundary of the incoming flow is set to the far-field boundary, the Mach number Ma is given 0.0075 (2.5m/s), and the inlet of the nozzle is set to the total temperature and total pressure inlet.

The size of the entire computing domain is 100D× 100D×250D (D=0.05m).

3. Analysis of results

3.1 Jet development

The 4 RTX 4090Ds took a total of 32 hours to calculate 100 CTU with a total of 128 GPU core hours (pictured), and you can clearly see the development process of the jet, and the velocity distribution of X/D=10 downstream of the nozzle can be seen to periodically fluctuate up and down the reference value.

3.2 Steady-state flow field

Compared with the results of Gerrit-Daniel Stich [1] using the LAVA solver and the WMLES model in a 210M grid, Dimaxer has the same capture effect on the nozzle jet shear boundary at a K3 accuracy of 1.2M grid.

The figure below shows the comparison results of the centerline velocity of the SMC001 jet after stabilization with the experimental value, and it can be seen that the Dimaxer calculation results are in good agreement with the experimental value.

summary 

In summary, Dimaxer's high-precision large eddy simulation of SMC001 can accurately capture the jet shear boundary with a small number of meshes, and the overall flow field is consistent with the experiment.

In the future, we will further demonstrate the high-confidence acoustic simulation capability of this example.