  The results of Brownian dynamics simulations of a single DNA molecule in
shear flow are presented taking into account the effect of internal viscosity.
The dissipative mechanism of internal viscosity is proved necessary in the
research of DNA dynamics. A stochastic model is derived on the basis of the
balance equation for forces acting on the chain. The Euler method is applied to
the solution of the model. The extensions of DNA molecules for different
Weissenberg numbers are analyzed. Comparison with the experimental results
available in the literature is carried out to estimate the contribution of the
effect of internal viscosity.
