- #1

- 1

- 0

## Main Question or Discussion Point

Hi I am trying to understand what forces are at work to slow a liquid flowing in a circular pipe

As an example the above torus pipe

I understand that a rotational flow pattern will be formed by the solid body rotation and the additional force of the solid container will prevent the formation of a free vortices ? is this correct ?

While I understand that viscosity works to slow the flow , are there other forces due to the circular flow geometry that work against the momentum of the fluid ?

Can either

Additionally would the answer be different if the pipe wasn't fully filled with an incompressible liquid ?

Is there anything else I need to consider to how quickly the momentum would stop ?

Any readings that someone could recommend ?

As an example the above torus pipe

__fully filled__with an incompressible low viscosity liquid. This is rotated until the fluid achieves solid body rotation and then the pipe is suddenly stopped but the low viscosity allows the fluid to continue under its own inertiaI understand that a rotational flow pattern will be formed by the solid body rotation and the additional force of the solid container will prevent the formation of a free vortices ? is this correct ?

While I understand that viscosity works to slow the flow , are there other forces due to the circular flow geometry that work against the momentum of the fluid ?

__Vorticity__- degrades kinetic energy trapped in Circulation to heat ? Can it diffuse the flow momentum any other way ?Can either

__Axial Pressure Variation__or -__Body Forces__The additional force applied by the solid container degrade the flow (some version of__Minor Losses in a pipe)__effect how fast the momentum is dissipated ?Additionally would the answer be different if the pipe wasn't fully filled with an incompressible liquid ?

Is there anything else I need to consider to how quickly the momentum would stop ?

Any readings that someone could recommend ?