Irreproducibility a secondary flow in a neighbourhood of the multiple bifurcation point

A problem for the influence of measurements on the values of observed quantities in the classic approximation is formalized. The research is confined to the Navier–Stokes's system and the connected with it heat equation. Their subspace of nontrivial solutions corresponding to a bifurcation point has the symplectic group $Gr\subset Sp(2,R)$.