Slip Boundary Formulation for Low-Pressure System

  • Last Post 01 November 2018
Devank12 posted this 31 October 2018

can any one explain me how to create slip boundary formation for above mentioned low pressure (<0.01 Pa)concentric tube?  


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seeta gunti posted this 31 October 2018


Slip boundary can be given if you define the boundary as wall. 

Can you elaborate more on your problem description and objective of the study for better understanding.




Devank12 posted this 31 October 2018

i am currently analysing flow through a concentric pipe using fluent. inner and outer pipes are made by copper and borosilicate glass respectively. the water flow inside the pipe is laminar. The space between the inner tube and outer cover tube made by vacuum (< 0.01Pa). i need to create a vacuum zone in the annulus gap.

rwoolhou posted this 01 November 2018

A useful approach for the vacuum section is to model it as a solid and adjust the conductivity to near enough zero: look up the Knudsen Number for continuum flow. You'll need to allow it to participate in radiation calculations otherwise the (I assume) solar energy won't get to the inner tube.