Relaxation of Orientational Variables

We can notice that, apart from the deformation of the coil, the stresses (6.7) are determined by the forces of internal viscosity which satisfy equation (7.3) or, in normal form, it is the last equation from set (7.4). It is convenient to consider quantities 

We use the last equation from (7.4) and equations (7.14) to obtain the equation of relaxation for above-defined quantities. After the procedure, which is quite similar to that used in Section 7.2, we write down 

Here terms containing velocity gradients in the second power are already excluded. 

In the second iteration, some of the terms in the above relation can be neglected, so that this relation is followed 

Now one can return to the first equation from the set (7.33) and, also using equation (7.21), obtain the equation of relaxation of the orientational variables 

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