Microfluidic Wall Conditions
Use the Microfluidic Wall Conditions node to add boundary conditions to the moving wall and specify whether to use viscous slip or thermal creep.
Boundary Condition
The default Boundary condition for the wall is Slip velocity. Enter values or expressions for the components of the Velocity of moving wall uw (SI unit: m/s).
Use Viscous Slip
Select the Use viscous slip checkbox to define the slip length:
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The default is User defined. Enter a value for Ls (SI unit: m). The default is 1e-7 m.
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Select Maxwell’s model to calculate it from:
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Then enter values or expressions for the Tangential momentum accommodation coefficient (TMAC) av (dimensionless) (the default is 0.9) and the Mean free path λ (SI unit: m) (the default is 1e-6 m).
Use Thermal Creep
Select the Use thermal creep checkbox to activate the thermal creep component of the boundary condition. Enter the fluid’s Temperature T (SI unit: K) and the Thermal slip coefficient σT. The default temperature is 293.15 K and the default thermal slip coefficient is 0.75.
If you also have a license for the MEMS Module, an additional Boundary condition option Electroosmotic velocity is available. This is described in the MEMS Module User’s Guide.