fieldCoordinateSystemTransform fails to write "U:Transformed" field on a Windows OS

Summary

fieldCoordinateSystemTransform function object attempts to write "U:Transformed" field on Windows OS even though the ":" character it not supported in file names. This results in the field not being written.

Steps to reproduce

This can be reproduced using a modified version of the simpleFoam pipeCyclic tutorial.

1. Open a OpenFOAM-MS-DOSPrompt.bat window
2. Navigate to the attached slightly modified pipeCyclic tutorial
3. Run simpleFoam

The log will show that the field is trying to be written, but it never shows up in the time directory.

functionObjects::fieldCoordinateSystemTransform coordinateTransform writing field: U:Transformed

Example case

pipeCyclic.zip

What is the current bug behaviour?

The U:Transformed is not written like it should be due to the Windows OS not supporting the ":" character in a file name.

What is the expected correct behavior?

U:Transformed needs to be written with a compatible file name.

Environment information

• OpenFOAM version : v1912
• Operating system : Windows 10
• Hardware info : Intel
• Compiler : MinGW
• Prompt : OpenFOAM-MS-DOSPrompt.bat

Possible fixes

The simplest fix in my opinion would be to add the ability to change the name of the written field in the fieldCoordinateSystemTransform function object using an option like...

fields ( (U U_Transformed) );