Navier-Stokes Equations in the Case of Two-Dimensional Flow

Navier-Stokes Equations in the case of Two-Dimensional Flow 

In the case of a low Reynolds number, the latter equations become the Stokes 

In any case, these are three equations for three unknown fimctions, v, v, p. The viscose stress tensor appears as 

The last component is the tangential stress in the case of a plane parallel flow. 

Capillary pressure is determined as K, where y is the interfacial tension (liquid-air or liquid-liquid), and K is the mean curvature of the interface. 

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