It is connected with the impossibility of obtaining ideally pure liquids without any “weak places” (gas bubbles, admixture, etc.) and with the circumstance that in experience, the rupture often happens not in the liquid volume but on the surface touching the walls of the vessels weakened by the existence of thin films, embryos, etc.
It is evident that the real experimental values of negative pressure are much less than the corresponding theoretic estimations. It means that an imaginable rope of completely pure water with the diameter of 0.01m can sustain a huge extending effort more than 105 N. For instance, the maximum negative pressure that may be sustained by ideally pure water is estimated as -109N/m2. Theoretic evaluations show that in pure liquids (without admixture, gas bubbles, etc.) negative pressure may reach large values while the liquid may stand significant extending efforts. There are several facts providing negative pressure to play an important role in some vital systems in living organisms, e.g., in the blood vessel system. Negative pressure appears in many thermohydrodynamic and biophysical processes in the environment e.g., it is a proved scientific fact that plant juice rises up the trees mainly due to negative pressure. Negative pressure is known to be one of the metastable states in which liquids can be extended up to a certain limit. Received results emphasize the necessity to take into account the role of the negative pressure as an energy factor in evaluation of many transient thermohydrodynamic processes in the Nature and production systems. It was proved that the negative pressure is one of the main factors causing hard troubles in some technological and natural processes. The new approach to generation of the negative pressure waves in impure, unclean fluids has allowed the creation of principally new energy saving technologies and installations to increase the effectiveness and efficiency of different production processes. The negative pressure can be considered as the factor of both useful and destroying energies. The possibility of creation of direct wave of negative pressure in real heterogeneous liquid systems was confirmed experimentally under the certain kinetic and hydraulic conditions. But this phenomenon has not been practically applied, being only a nice lab toy due to the special demands for the purity and homogeneity of the liquids for its appearance.
Donny’s tests, the great values of negative pressure have been achieved. For more than 100 years of the laboratory researches beginning from F. Abstr a ct-Negative pressure phenomenon appears in many thermodynamic, geophysical and biophysical processes in the Nature and technological systems.
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