flow stream direction backwards for backward integration

[leighorf]

Describe the bug

Backward and bi-directional flow indicate flow in the wrong (opposite) direction when "Show Stream Direction" is checked.

Helpful additional information
(Please click check boxes AFTER submitting ticket)

• Did VAPOR crash?
• Did you get wrong results?

Impact

• High - User productivity significantly degraded
• Medium - User productivity partially degraded
• Low - User productivity trivially degraded

To Reproduce

Steps to reproduce the behavior. For example:

1. Create a Flow object, and choose either bi-directional or backwards flow
2. Under "appearance" check "Show Stream Direction"
3. Notice that the flow direction is in the wrong direction for the backwards flow

Expected behavior

Flow direction should be in the correct direction.

Attachments

Desktop

• Fedora 40
• Vapor 3.9.2 AppImage

[leighorf]

I have shaded the streamlines by vertical motion, where red is positive. So arrows should point upwards if they are red and downwards if blue.

In the first (top) image I checked "Forward" for flow direction, and it displays correctly.
In the second (middle) image I checked "Backwards" for flow direction and all streamtubes are indicating the wrong (opposite) direction
In the third (bottom) image I chose "Bi-Directional" and you can see how the forward part is right but the backwards part is wrong.