Experimental simulation results of magnetohydrodynamic (MHD) effect instabilities caused by coating cracks on insulating layer in pipes are presented. The results showed that the cracks induced not only a great increase of MHD pressure drop
but also unsteadiness of MHD effect. Deviated from the classical laws
both the boundary potential difference U and MHD pressure drop Δ P jumped to an extent over 100%. Moreover
under the same experimental parameters
U vibrated with time and Δ P vibrated with velocity V 0.