Computer simulation of physical processes including modeling of laminar-to-turbulent transition

1. A method for modifying a simulation of fluid flow activity on a computer, the method comprising:

performing a first calculation where fluid flow at a local boundary layer is assumed to be a laminar fluid flow at the local boundary layer;

performing a second calculation where the fluid flow at the local boundary layer is assumed to be a turbulent fluid flow at the local boundary layer; and

modifying the simulation of the fluid flow activity based on a result from the first calculation, a result from the second calculation or a combination of the result of the first and the result of the second calculation.

2. The method of claim 1 wherein performing the first calculation, further comprises:

selecting the results of the first calculation and the second calculation or the combination according to a criterion that is related to a level of local turbulence intensity.

3. The method of claim 1 wherein the first calculation comprises calculating a wall momentum flux tensor property for a laminar flow, the second calculation comprises calculating a wall momentum flux tensor property for a turbulent flow; and the method further comprises:

selecting the laminar wall momentum flux tensor property or the turbulent wall momentum flux tensor property for modifying the simulation.

4. The method of claim 1 , further comprising:

determining a laminar to turbulent boundary layer transition by:

determining, for each of multiple facets on a boundary surface, a first measure based on the first calculation and a second measure based on the second calculation; and

classifying fluid flow for at least some of the multiple facets as laminar or turbulent by comparing at least one of the first and second measures to a criterion.

5. The method of claim 4 , further comprising:

selecting a wall momentum flux tensor property for laminar flow for facets of the multiple facets classified as laminar; and

selecting a wall momentum flux tensor property for turbulent flow for facets of the multiple facets classified as turbulent.

6. The method of claim 4 , wherein a result of the first calculation comprises a measure of laminar wall momentum flux tensor, a result of the second calculation comprises a measure of turbulent wall momentum flux tensor, and the criterion comprises a measure of turbulence intensity.

7. The method of claim 1 , wherein: the first calculation provides a measure of laminar wall momentum flux tensor and the second calculation provides a measure of turbulent wall momentum flux tensor, with the method further comprising:

comparing, for each of multiple facets on the boundary surface, a calculated measure of turbulence intensity and the measure of turbulent wall momentum flux tensor; and

selecting, for at least some of the multiple facets on the boundary surface, one of the calculated turbulent wall momentum flux tensor and laminar wall momentum flux tensor, based on the comparison.

8. The method of claim 7 , wherein comparing comprises:

determining if the measure of turbulence intensity is greater than the measure of wall momentum flux tensor; and

selecting comprises, for a particular facet:

selecting either the turbulent wall momentum flux tensor if the measure of turbulence intensity is greater than the measure of turbulent wall momentum flux tensor or the measure of laminar wall momentum flux tensor if the measure of turbulence intensity is less than the measure of turbulent wall momentum flux tensor.

9. The method of claim 7 , wherein for a given near-wall fluid velocity, the measure of turbulent wall momentum flux tensor is greater than the measure of laminar wall momentum flux tensor.

10. The method of claim 1 , further comprising:

calculating a value of local turbulent kinetic energy.

11. The method of claim 1 , further comprises:

simulating activity of fluid in a volume by:

performing interaction operations on state vectors, the interaction operations modeling interactions between elements of different momentum states according to a model; and

performing first move operations of the state vectors to reflect movement of elements to new voxels in the volume according to the model.

12. The method of claim 1 wherein the second calculation comprises a calculation to determine a measure of turbulent wall momentum flux tensor based on a velocity profile and a wall distance.

13. The method of claim 1 , further comprising:

selecting, for at least some of multiple facets on a boundary surface, a value that is based on a weighted average of a result of the first calculation and a result of the second calculation.

14. The method of claim 1 , further comprising:

selecting, for at least some of the multiple facets on the boundary surface, a wall momentum flux tensor property that is based on a combination of a turbulent wall momentum flux tensor property and a laminar wall momentum flux tensor property.

15. The method of claim 1 wherein the second calculation comprises a calculation to determine a measure of turbulent wall momentum flux tensor based on local turbulent kinetic energy and a local fluid velocity.

16. The method of claim 1 wherein a voxel size in a region adjacent to the boundary surface is similar to a voxel size at regions spaced apart from the boundary surface.

17. The method of claim 1 wherein a voxel size in a region adjacent to the boundary surface is the same as a voxel size at regions spaced apart from the boundary surface.

18. A memory device that is either a volatile or non-volatile memory that stores executable computer instructions for modifying a simulation of fluid flow activity on a computer, the instructions being executable to cause the computer to:

perform a first calculation where fluid flow at a local boundary layer is assumed to be a laminar fluid flow at the local boundary layer;

perform a second calculation where the fluid flow at the local boundary layer is assumed to be a turbulent fluid flow at the local boundary layer; and

modify the simulation of the fluid flow activity based on the first calculation, the second calculation or a combination of the first and second calculations.

19. A computer system for modifying a simulation of fluid flow activity, comprising:

one or more processors devices;

memory coupled to the one or more processor devices; and

computer storage devices storing instructions that are executable by the one or more processors devices to cause the system to:

perform a first calculation where fluid flow at a local boundary layer is assumed to be a laminar fluid flow at the local boundary layer;

perform a second calculation where the fluid flow at the local boundary layer is assumed to be a turbulent fluid flow at the local boundary layer; and

modifying the simulation of fluid flow activity, based on the first calculation, the second calculation or a combination of the first and second calculations.

20. The computer system of claim 19 , wherein the operations further comprise:

selecting the results of the first calculation and the second calculation or the combination according to a criterion that is related to a level of local turbulence intensity.