vk.com/club152685050Using a Single Rotating Reference| vk.com/id446425943Frame

Figure 9.10: wall-6 — RNG k- ε and Standard k- ε Solutions (x=0 cm to x=43 cm)

9.5. Summary

This tutorial illustrated the setup and solution of a 2D, axisymmetric disk cavity problem in ANSYS Fluent. The ability to calculate a swirl velocity permits the use of a 2D mesh, thereby making the calculation simpler and more economical to run than a 3D model. This can be important for problems where the enhanced wall treatment is used, and the near-wall flow field is resolved using a fine mesh (the first mesh point away from the wall being placed at a y+ on the order of 1).

For more information about mesh considerations for turbulence modeling, see the Fluent User's Guide.

9.6. Further Improvements

The case modeled in this tutorial lends itself to parametric study due to its relatively small size. Here are some things you may want to try:

•Separate wall-6 into two walls.

Domain → Zones → Separate → Faces...

Specify one wall to be stationary, and rerun the calculation.

•Use adaption to see if resolving the high velocity and pressure-gradient region of the flow has a significant effect on the solution.

•Introduce a nonzero swirl at the inlet or use a velocity profile for fully-developed pipe flow. This is probably more realistic than the constant axial velocity used here, since the flow at the inlet is typically being supplied by a pipe.

•Model compressible flow (using the ideal gas law for density) rather than assuming incompressible flow text.

	Release 2019 R1 - © ANSYS,Inc.All rights reserved.- Contains proprietary and confidential information
352	of ANSYS, Inc. and its subsidiaries and affiliates.

vk.com/club152685050 | vk.com/id446425943

References

This tutorial guides you through the steps to reach an initial solution. You may be able to obtain a more accurate solution by using an appropriate higher-order discretization scheme and by adapting the mesh. Mesh adaption can also ensure that the solution is independent of the mesh. These steps are demonstrated in Fluid Flow and Heat Transfer in a Mixing Elbow (p. 35).

9.7. References

1.Pincombe, J.R.,“Velocity Measurements in the Mk II - Rotating Cavity Rig with a Radial Outflow”, ThermoFluid Mechanics Research Centre, University of Sussex, Brighton, UK, 1981.

Release 2019 R1 - © ANSYS,Inc.All rights reserved.- Contains proprietary and confidential information
of ANSYS, Inc. and its subsidiaries and affiliates.	353

vk.com/club152685050 | vk.com/id446425943

	Release 2019 R1 - © ANSYS,Inc.All rights reserved.- Contains proprietary and confidential information
354	of ANSYS, Inc. and its subsidiaries and affiliates.