Flow along the helical axis

Helfrich proposed a simple physical mechanism, which he called 

The energy gained by the motion in the pressure gradient should be equal 

Typically, R 500 pm and P = Injq 1 pm so that j/ pp which explains the very high viscosity at low pressure gradients. 

We shall now show that the essential features of Helfrich s model can be derived on the basis of the Ericksen-Leslie theory.  

We shall consider flow between two parallel plates, caused by a pressure gradient. Choosing a right-handed cartesian system such that the plates occupy. X = +A, we seek solutions of the form 

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Often, in practical cases, qh is so large that sm qh/qh is negligibly small and / pp approaches a maximum limiting value which is independent of the pitch or gap width. This value is several orders of magnitude less than that for flow along the helical axis and is comparable to that for a nematic. 

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